Network Working Group S. Hu Internet-Draft China Mobile Intended status: Informational D. Eastlake Expires: December 5, 2019 M. Chen Huawei Technologies F. Qin Z. Li China Mobile T. Chua Singapore Telecommunications Limited D. Huang ZTE June 03, 2019 The China Mobile, Huawei, and ZTE BNG Simple Control and User Plane Separation Protocol (S-CUSP) draft-chz-simple-cu-separation-bng-protocol-00 Abstract To support Control Plane (CP) and User Plane (UP) Separation (CUPS) for fixed network Broadband Network Gateway (BNG) service providers, China Mobile, Huawei Technologies, and ZTE have developed a simple CUPS control channel Protocol (S-CUSP). This document is intended to make the S-CUSP specification conveniently available to the Internet community. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on November 24, 2019. Hu, et al. Expires November 24, 2019 [Page 1] Internet-Draft S-CUSP for BNG May 2019 Copyright Notice Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. BNG CUPS Overview . . . . . . . . . . . . . . . . . . . . . . 8 3.1. BNG CUPS Motivation . . . . . . . . . . . . . . . . . . . 8 3.2. BNG CUPS Architecture Overview . . . . . . . . . . . . . 8 3.3. BNG CUPS Interfaces . . . . . . . . . . . . . . . . . . . 10 3.3.1. Service Interface . . . . . . . . . . . . . . . . . . 11 3.3.2. Management Interface . . . . . . . . . . . . . . . . 11 3.3.3. Control Interface . . . . . . . . . . . . . . . . . . 11 3.4. BNG CUPS Procedure Overview . . . . . . . . . . . . . . . 12 4. S-CUSP Protocol Overview . . . . . . . . . . . . . . . . . . 14 4.1. Control Channel Related Procedures . . . . . . . . . . . 14 4.1.1. S-CUSP Session Establishment . . . . . . . . . . . . 14 4.1.2. Keep Alive . . . . . . . . . . . . . . . . . . . . . 16 4.2. Node Related Procedures . . . . . . . . . . . . . . . . . 16 4.2.1. UP Board and Interface Status Report . . . . . . . . 16 4.2.2. Enable BAS Function on Access Interface . . . . . . . 17 4.2.3. Advertise Subscriber Network Routing . . . . . . . . 17 4.2.4. CGN Public IP Address Allocation . . . . . . . . . . 18 4.2.5. Data Synchronization Between CP and UP . . . . . . . 19 4.3. Subscriber Session Related Procedures . . . . . . . . . . 20 4.3.1. Create Subscriber Session . . . . . . . . . . . . . . 21 4.3.2. Update Subscriber Session . . . . . . . . . . . . . . 22 4.3.3. Delete Subscriber Session . . . . . . . . . . . . . . 23 4.3.4. Subscriber Session Events Report . . . . . . . . . . 23 5. S-CUSP Call Flows . . . . . . . . . . . . . . . . . . . . . . 24 5.1. IPoE . . . . . . . . . . . . . . . . . . . . . . . . . . 24 5.1.1. DHCPv4 Access . . . . . . . . . . . . . . . . . . . . 24 5.1.2. DHCPv6 Access . . . . . . . . . . . . . . . . . . . . 26 5.1.3. IPv6 SLAAC Access . . . . . . . . . . . . . . . . . . 28 5.1.4. DHCPv6 + SLAAC Access . . . . . . . . . . . . . . . . 30 Hu, et al. Expires November 24, 2019 [Page 2] Internet-Draft S-CUSP for BNG May 2019 5.1.5. DHCP Dual Stack Access . . . . . . . . . . . . . . . 32 5.1.6. L2 Static Subscriber Access . . . . . . . . . . . . . 35 5.2. PPPoE . . . . . . . . . . . . . . . . . . . . . . . . . . 37 5.2.1. IPv4 PPPoE Access . . . . . . . . . . . . . . . . . . 37 5.2.2. IPv6 PPPoE Access . . . . . . . . . . . . . . . . . . 39 5.2.3. PPPoE Dual Stack Access . . . . . . . . . . . . . . . 41 5.3. WLAN Access . . . . . . . . . . . . . . . . . . . . . . . 43 5.4. L2TP . . . . . . . . . . . . . . . . . . . . . . . . . . 46 5.4.1. L2TP LAC Access . . . . . . . . . . . . . . . . . . . 46 5.4.2. L2TP LNS IPv4 Access . . . . . . . . . . . . . . . . 47 5.4.3. L2TP LNS IPv6 Access . . . . . . . . . . . . . . . . 49 5.5. CGN (Carrier Grade NAT) . . . . . . . . . . . . . . . . . 52 5.6. L3 Leased Line Access . . . . . . . . . . . . . . . . . . 54 5.6.1. Web Authentication . . . . . . . . . . . . . . . . . 54 5.6.2. User Traffic Trigger . . . . . . . . . . . . . . . . 57 5.7. Multicast Access . . . . . . . . . . . . . . . . . . . . 58 6. S-CUSP Message Formats . . . . . . . . . . . . . . . . . . . 60 6.1. Common Message Header . . . . . . . . . . . . . . . . . . 60 6.2. Control Messages . . . . . . . . . . . . . . . . . . . . 61 6.2.1. Hello Message . . . . . . . . . . . . . . . . . . . . 61 6.2.2. Keepalive Message . . . . . . . . . . . . . . . . . . 62 6.2.3. Synch_Request Message . . . . . . . . . . . . . . . . 62 6.2.4. Sync_Begin Message . . . . . . . . . . . . . . . . . 62 6.2.5. Sync_Data Message . . . . . . . . . . . . . . . . . . 63 6.2.6. Sync_End Message . . . . . . . . . . . . . . . . . . 64 6.2.7. Update_Request Message . . . . . . . . . . . . . . . 64 6.2.8. Update_Response Message . . . . . . . . . . . . . . . 64 6.3. Event Message . . . . . . . . . . . . . . . . . . . . . . 65 6.4. Report Message . . . . . . . . . . . . . . . . . . . . . 66 6.5. CGN Messages . . . . . . . . . . . . . . . . . . . . . . 66 6.5.1. Addr_Allocation_Req Message . . . . . . . . . . . . . 66 6.5.2. Addr_Allocation_Ack Message . . . . . . . . . . . . . 66 6.5.3. Addr_Renew_Req Message . . . . . . . . . . . . . . . 66 6.5.4. Addr_Renew_Ack Message . . . . . . . . . . . . . . . 67 6.5.5. Addr_Release_Req Message . . . . . . . . . . . . . . 67 6.5.6. Addr_Release_Ack Message . . . . . . . . . . . . . . 67 6.6. Vendor Message . . . . . . . . . . . . . . . . . . . . . 67 7. S-CUSP TLVs and Sub-TLVs . . . . . . . . . . . . . . . . . . 67 7.1. Common TLV Header . . . . . . . . . . . . . . . . . . . . 68 7.2. Basic Data Fields . . . . . . . . . . . . . . . . . . . . 68 7.3. Sub-TLV Format and Sub-TLVs . . . . . . . . . . . . . . . 69 7.3.1. Name sub-TLVs . . . . . . . . . . . . . . . . . . . . 70 7.3.2. Ingress-CAR sub-TLV . . . . . . . . . . . . . . . . . 70 7.3.3. Egress-CAR sub-TLV . . . . . . . . . . . . . . . . . 71 7.3.4. If-Desc sub-TLV . . . . . . . . . . . . . . . . . . . 71 7.3.5. IPv6 Address List sub-TLV . . . . . . . . . . . . . . 73 7.4. The Hello TLV . . . . . . . . . . . . . . . . . . . . . . 73 7.5. The Keep Alive TLV . . . . . . . . . . . . . . . . . . . 75 Hu, et al. Expires November 24, 2019 [Page 3] Internet-Draft S-CUSP for BNG May 2019 7.6. The Error Information TLV . . . . . . . . . . . . . . . . 75 7.7. BAS Function Enabler TLV . . . . . . . . . . . . . . . . 76 7.8. Routing TLVs . . . . . . . . . . . . . . . . . . . . . . 79 7.8.1. IPv4 Routing TLV . . . . . . . . . . . . . . . . . . 79 7.8.2. IPv6 Routing TLV . . . . . . . . . . . . . . . . . . 80 7.9. Subscriber TLVs . . . . . . . . . . . . . . . . . . . . . 82 7.9.1. Basic Subscriber TLV . . . . . . . . . . . . . . . . 82 7.9.2. PPP Subscriber TLV . . . . . . . . . . . . . . . . . 85 7.9.3. IPv4 Subscriber TLV . . . . . . . . . . . . . . . . . 86 7.9.4. IPv6 Subscriber TLV . . . . . . . . . . . . . . . . . 87 7.9.5. IPv4 Static Subscriber TLV . . . . . . . . . . . . . 89 7.9.6. IPv6 Static Subscriber TLV . . . . . . . . . . . . . 90 7.9.7. L2TP-LAC Subscriber TLV . . . . . . . . . . . . . . . 91 7.9.8. L2TP-LNS Subscriber TLV . . . . . . . . . . . . . . . 92 7.9.9. L2TP-LAC Tunnel TLV . . . . . . . . . . . . . . . . . 93 7.9.10. L2TP-LNS Tunnel TLV . . . . . . . . . . . . . . . . . 94 7.9.11. Session Update Response TLV . . . . . . . . . . . . . 95 7.9.12. Subscriber Policy TLV . . . . . . . . . . . . . . . . 95 7.9.13. Subscriber CGN Port Range TLV . . . . . . . . . . . . 97 7.10. Device Status TLVs . . . . . . . . . . . . . . . . . . . 97 7.10.1. Interface Status TLV . . . . . . . . . . . . . . . . 97 7.10.2. Board Status TLV . . . . . . . . . . . . . . . . . . 98 7.11. CGN TLVs . . . . . . . . . . . . . . . . . . . . . . . . 99 7.11.1. Address Allocation Request TLV . . . . . . . . . . . 99 7.11.2. Address Allocation Response TLV . . . . . . . . . . 100 7.11.3. Address Renewal Request TLV . . . . . . . . . . . . 101 7.11.4. Address Renewal Response TLV . . . . . . . . . . . . 102 7.11.5. Address Release Request TLV . . . . . . . . . . . . 103 7.11.6. Address Release Response TLV . . . . . . . . . . . . 103 7.12. Event TLVs . . . . . . . . . . . . . . . . . . . . . . . 104 7.12.1. Subscriber Traffic Statistics TLV . . . . . . . . . 104 7.12.2. Subscriber Detection Result TLV . . . . . . . . . . 106 7.13. Vendor TLV . . . . . . . . . . . . . . . . . . . . . . . 107 8. Implementation Status . . . . . . . . . . . . . . . . . . . . 108 8.1. Implementations . . . . . . . . . . . . . . . . . . . . . 108 8.1.1. Huawei Technologies . . . . . . . . . . . . . . . . . 109 8.1.2. ZTE . . . . . . . . . . . . . . . . . . . . . . . . . 109 8.1.3. H3C . . . . . . . . . . . . . . . . . . . . . . . . . 109 8.2. Hackathon . . . . . . . . . . . . . . . . . . . . . . . . 109 8.3. EANTC Testing . . . . . . . . . . . . . . . . . . . . . . 110 9. Summary of Major S-CUSP Codepoints . . . . . . . . . . . . . 110 9.1. Message Types . . . . . . . . . . . . . . . . . . . . . . 110 9.2. TLV Types . . . . . . . . . . . . . . . . . . . . . . . . 111 9.3. TLV Operation Codes . . . . . . . . . . . . . . . . . . . 112 9.4. Sub-TLV Types . . . . . . . . . . . . . . . . . . . . . . 112 9.5. Error Codes . . . . . . . . . . . . . . . . . . . . . . . 113 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 115 11. Security Considerations . . . . . . . . . . . . . . . . . . . 115 Hu, et al. Expires November 24, 2019 [Page 4] Internet-Draft S-CUSP for BNG May 2019 12. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 115 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 116 14. Informative References . . . . . . . . . . . . . . . . . . . 116 Appendix A. An Appendix . . . . . . . . . . . . . . . . . . . . 117 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 117 1. Introduction A fixed network Broadband Network Gateway (BNG) is an Ethernet- centric IP edge router, and the aggregation point for user traffic. To provide centralized session management, flexible address allocation, high scalability for subscriber management capacity, and cost-efficient redundancy, the Control/User (CU) separated BNG framework is described in [TR-384]. The CU separated service Control Plane (CP), which is responsible for user access authentication and setting forwarding entries in User Planes (UPs), can be virtualized and centralized. The routing control and forwarding plane, i.e. the BNG user plane (local), can be distributed across the infrastructure. Other structures can also be supported such as both CP and UP being virtual or both being physical. This document specifies the Simple CU Separation BNG control channel Protocol (S-CUSP) for communications between a BNG Control Plane (CP) and a set of User Planes (UPs). S-CUSP is designed to be flexible and extensible so as to easily allow for additional messages and data items, should further requirements be expressed in the future. S-CUSP was designed by China Mobile, Huawei Technologies, and ZTE, has been implemented by Huawei Technologies, ZTE, and H3C, and has been deployed by China Mobile. 2. Terminology This section specifies acronyms used in this document. AAA: Authentication Authorization Accounting. ACK: Acknowledgement message. BNG: Broadband Network Gateway. A broadband remote access server (BRAS (BRoadband Access Server), B-RAS or BBRAS) routes traffic to and from broadband remote access devices such as digital subscriber line access multiplexers (DSLAM) on an Internet Service Provider's (ISP) network. BRAS can also be referred to as a Broadband Network Gateway (BNG). BRAS: BRoadband Access Server (BNG). Hu, et al. Expires November 24, 2019 [Page 5] Internet-Draft S-CUSP for BNG May 2019 BAS:Broadband ACCESS Service. CAR: Committed Access Rate. CBS: Committed Burst Size. CGN: Carrier Grade NAT. Ci: Control Interface. CIR: Committed Information Rate. CoA: Change of Authorization. CP: Control Plane. CP is a user control management component which supports the management of the UP's resources such as the user entry and forwarding policy. CPE: Customer Premises Equipment. CU: Control-plane / User-plane. CUSP: Control and User plane Separation Protocol. DEI: Drop Eligibility Indicator. A bit in a VLAN tag after the priority and before the VLAN ID. (This bit was formerly the CFI (Canonical Format Indicator).) [802.1Q] DHCP: Dynamic Host Configuration Protocol [RFC2131]. dial-up: This refers to the initial connection messages when a new user appears. The name is left over from when users literally dialed up on a modem equipped phone line but herein is applied to other initial connection techniques. Initial connection is frequently indicated by the receipt of packets over PPPoE or IPoE. EMS: Element Management System. IPoE: IP over Ethernet. L2TP: Layer 2 Tunneling Protocol [RFC2661]. LAC: L2TP Access Concentrator. LNS: L2TP Network Server. Hu, et al. Expires November 24, 2019 [Page 6] Internet-Draft S-CUSP for BNG May 2019 MAC: 48-bit Media Access Control address [RFC7042]. MANO: Management and Orchestration. Mi: Management Interface. MSS: Maximum Segment Size. MRU: Maximum Receive Unit. NAT: Network Address Translation [RFC3022]. ND: Neighbor Discovery. NFV: Network Function Virtualization. NFVI: NFV Infrastructure PBS: Peak Burst Size. PD: Prefix Delegation. PIR: Peak Information Rate. PPP: Point to Point Protocol [RFC1661]. PPPoE: PPP over Ethernet. S-CUSP: Simple Control and User Plane Separation Protocol. Si: Service Interface. TLV: Type, Length, Value. See Section 4.2. UP: User Plane. UP is a network edge and user policy implementation component. The traditional router's Control Plane and Forwarding Plane are both preserved on BNG devices in the form of a user plane. URPF: Unicast Reverse Path Forwarding. User: Equivalent to "customer", "subscriber". VRF: Virtual Routing and Forwarding. Hu, et al. Expires November 24, 2019 [Page 7] Internet-Draft S-CUSP for BNG May 2019 3. BNG CUPS Overview 3.1. BNG CUPS Motivation The rapid development of new services, such as 4K TV, IoT, etc., and increasing numbers of home broadband service users present some new challenges for BNGs such as: Low resource utilization: The traditional BNG acts as both a gateway for user access authentication and accounting and an IP network's Layer 3 edge. The mutually affecting nature of the tightly coupled control plane and forwarding plane makes it difficult to achieve the maximum performance of either plane. Complex management and maintenance: Due to the large numbers of traditional BNGs, configuring each device in a network is very tedious when deploying global service policies. As the network expands and new services are introduced, this deployment mode will cease to be feasible as it is unable to manage services effectively and rectify faults rapidly. Slow service provisioning: The coupling of control plane and forwarding plane, in addition to a distributed network control mechanism, means that any new technology has to rely heavily on the existing network devices. To address these challenges for fixed networks, the framework for a cloud-based BNG with Control-Plane and User-Plane (CU) separation is described in [TR-384]. The main idea of CU separation is to extract and centralize the user management functions of multiple BNG devices, forming a unified and centralized Control Plane (CP). And the traditional router's Control Plane and Forwarding Plane are both preserved on BNG devices in the form of a User Plane (UP). Note that the CU separation concept has also been introduced in the 3GPP 5G architecture [3GPP.23.501]. 3.2. BNG CUPS Architecture Overview The functions in a traditional BNG can be divided into two parts: one is the user access management function, the other is the router function. In a cloud-based BNG, we find that splitting these two functions apart can make a difference. The user management function can be centralized and deployed as a concentrated module or device, called the BNG-CP (Control Plane). The other functions, such as the router function and forwarding engine, can be deployed in the form of the BNG User Plane. Thus, the Cloud-based BNG architecture is made up of Control Plane and User Plane. Hu, et al. Expires November 24, 2019 [Page 8] Internet-Draft S-CUSP for BNG May 2019 The following figure shows the architecture of CU separated BNG: +------------------------------------------------------------------+ | Neighboring policy and resource management systems | | | | +-------------+ +-----------+ +---------+ +----------+ | | |AAA Server| |DHCP Server| | EMS | | MANO | | | +-------------+ +-----------+ +---------+ +----------+ | +------------------------------------------------------------------+ +------------------------------------------------------------------+ | CU-separated BNG system | | +--------------------------------------------------------------+ | | | +----------+ +----------+ +------++------++-----------+ | | | | | Address | |Subscriber| | AAA ||PPPoE/|| UP | | | | | |management| |management| | ||IPoE ||management | | | | | +----------+ +----------+ +------++------++-----------+ | | | | CP | | | +--------------------------------------------------------------+ | | | | | | | | +---------------------------+ +--------------------------+ | | | +------------------+ | | +------------------+ | | | | | Routing control | | | | Routing control | | | | | +------------------+ | ... | +------------------+ | | | | +------------------+ | | +------------------+ | | | | |Forwarding engine | | | |Forwarding engine | | | | | +------------------+ UP | | +------------------+ UP| | | +---------------------------+ +--------------------------+ | +------------------------------------------------------------------+ Figure 3.1: Architecture of CU Separated BNG As shown in Figure 3.1, the BNG Control Plane could be virtualized and centralized, which provides benefits such as centralized session management, flexible address allocation, high scalability for subscriber management capacity, and cost-efficient redundancy, etc. The functional components inside the BNG Service Control Plane can be implemented as Virtual Network Functions (VNFs) and hosted in a Network Function Virtualization Infrastructure (NFVI). The User Plane Management module in the BNG Control Plane centrally manages the distributed BNG User Planes (e.g. load balancing), as well as the setup, deletion, and maintenance of channels between Control Planes and User Planes. Other modules in the BNG control plane, such as address management, AAA, etc., are responsible for the connection with outside subsystems in order to fulfill those services. Note that the User Plane shouldsupport both physical and Hu, et al. Expires November 24, 2019 [Page 9] Internet-Draft S-CUSP for BNG May 2019 virtual network functions. For example, BNG user plane L3 forwarding related network functions can be disaggregated and distributed across the physical infrastructure. And the other control plane and management plane functions in the CU Separation BNG can be moved into the NFVI for virtualization [TR-384]. The details of CU separated BNG's function components are as following: The Control Plane should support: 1. Address management: unified address pool management and CGN subscriber address traceability management. 2. AAA: This component performs Authentication, Authorization and Accounting, together with RADIUS/DIAMETER. The BNG communicates with the AAA server to check whether the subscriber who sent an Access-Request has network access authority. Once the subscriber goes online, this component together with the Service Control component implement accounting, data capacity limitation, and QoS enforcement policies. 3. Subscriber management: user entry management and forwarding policy management. 4. PPPoE/IPoE: process user dial-up packets via PPPoE/IPoE. 5. UP management: management of UP interface status, and the setup, deletion, and maintenance of channels between CP and UP. The User Plane should support: 1. Control plane functions including routing, multicast, and MPLS. 2. Forwarding plane functions including traffic forwarding, QoS and traffic statistics collection. 3. Subscriber detection, to detect whether an subscriber is still online. 3.3. BNG CUPS Interfaces To support the communication between the Control Plane and User Plane, three interfaces are defined. These are referred to as the Control Interface (Ci), Service Interface (Si) and Management Interface (Mi) as shown in Figure 3.2. Hu, et al. Expires November 24, 2019 [Page 10] Internet-Draft S-CUSP for BNG May 2019 +-----------------------------------+ | | | BNG-CP | | | +--+--------------+--------------+--+ | | | 1. Service | 2. Control | 3. Management| Interface | Interface | Interface | (Si) | (Ci) | (Mi) | | | | +--+--------------+--------------+--+ | | | BNG-UP | | | +-----------------------------------+ Figure 3.2: Interfaces Between the CP and UP of the BNG 3.3.1. Service Interface For a traditional BNG (without CU separation), the user dial-up signals are terminated and processed by the control plane of a BNG. When the CP and UP of a BNG are separated, there needs to be a way to relay these signals between the CP and the UP. The Service Interface (Si) is used to establish tunnels between the CP and UP. The tunnels are responsible for relaying the PPPoE, IPoE, and L2TP related control packets that are received from an RG over those tunnels. The detail definition of Si is out of the scope of this document. 3.3.2. Management Interface NETCONF [RFC6241] is the protocol used on the Management Interface between a CP and UP. It is used to configure the parameters of the Control Interface, Service Interface, the Access interfaces and QoS/ ACL Templates. The definitions of the parameters are out of the scope of this document. 3.3.3. Control Interface The CP uses the Control Interface to deliver service entries, and the UP uses this interface to report service events to the CP. A carrying protocol for this interface is specified in this document. Hu, et al. Expires November 24, 2019 [Page 11] Internet-Draft S-CUSP for BNG May 2019 3.4. BNG CUPS Procedure Overview The following numbered sequences gives a high level view of the main BNG CUPS procedures. RG UP CP AAA | | | | | |Establish S-CUSP Channel| | | 1|<---------------------->| | | | | | | | Report Board/interface | | | | status | | | 2|------to CP via Ci----->| | | | | | | | Enable BAS function | | | 3|<-----on UP via Ci------| | | | | | | | Notify UP to advertise | | | | subscriber network | | | | routing | | | 4|<------- via Ci---------| | | | | | | Dial-up Req | | | 5.1|-------------->| | | | | Relay the Dial-up Req | | | 5.2|-----to CP via Si------>| Authentication| | | | Req/Rep | | | 5.3|<------------->| | | Send the Dial-up Rep | | | 5.4|<----to UP via Si-------| | | Dial-up Rep | | | 5.5|<--------------| | | | | Create subscriber | | | | session on UP | | | 5.6|<--------via Ci-------->| | | | | CoA Request | | | 6.1|<--------------| | | Update session on UP | | | 6.2|<--------via Ci-------->| | | | | CoA Response | | | 6.3|-------------->| | | | | | Offline Req | | | 7.1|-------------->| | | | | Relay the Offline Req | | | 7.2|------to CP via Si----->| | | | | | | | Send the Offline Rep | | Hu, et al. Expires November 24, 2019 [Page 12] Internet-Draft S-CUSP for BNG May 2019 | 7.3|<-----to UP via Si------| | | Offline Rep | | | 7.4|<--------------| | | | | Delete session on UP | | | 7.5|<--------via Ci-------->| | | | | | | | Event report | | | 8|---------via Ci-------->| | | | | | | | Data Synchronization | | | 9|<--------via Ci-------->| | | | | | | | CGN Address Allocation | | | 10|<--------via Ci-------->| | | | | | Figure 3.3: BNG CUPS Overview Procedures 1. S-CUSP session establishment: This is the first step of BNG CUPS procedures. Once the Control Interface parameters are configured on a UP. It will start to setup S-CUSP session(s) with the specified CP(s). The detailed definition of S-CUSP session establishment can be found in Section 4.1.1. 2. Board and interface report: Once the S-CUSP session is established between a UP and a CP, the UP will report the status information on the board(s) and access side interface(s) of this UP to the CP. The CP can use this information to enable the Broadband Access Service (BAS) function (e.g., IPoE, PPPoE, etc.) on the specified interface(s). See Sections 4.2.1 and 7.10 for more details on Resource reporting. 3. BAS (Broadband Access Service) function enable: To enable the BAS function on the specified interfaces(s) of a UP. 4. Subscriber network route advertisement: The CP will allocate one or more address blocks to a UP. Each address block contains a series of IP addresses. Those IP addresses will be allocated to subscribers who are dialing up from the UP. To enable other nodes in the network to learn how to reach the subscribers, the CP needs to notify the UP to advertise the routes that can reach those IP addresses to the network. 5. 5.1-5.6 is a general call flow of a subscriber dial-up process. When a UP receives a dial-up request, it will relay the request packet to a CP through the Service Interface. The CP will parse the request. If everything is OK, it will send an authentication request to the AAA server to authenticate the Hu, et al. Expires November 24, 2019 [Page 13] Internet-Draft S-CUSP for BNG May 2019 subscriber. Once the subscriber passes the authentication, the AAA server will return a positive response to the CP. Then the CP will send the dial-up response packet to the UP and the UP will forward the response packet to the subscriber (RG). At the same time, the CP will create a subscriber session on the UP, which enables the subscriber to access the network. For different access types, the process may be a bit different. But the high-level process is similar. For each access type, the detail process can be found in Section 5. 6. 6.1-6.2 is the sequence when updating an existing session. The AAA server initiates a Change of Authorization (CoA) and sends the CoA to the CP. The CP will then update the session according to the CoA. See Section 4.3.2 for more detail on CP messages updating UP tables. 7. 7.1-7.5 is the sequence for deleting an existing session. When a UP receives a offline request, it will relay the request to a CP through the Service Interface. The CP will send back a response to the UP through the Service Interface. The UP will forward the offline response to the subscriber. Then the CP will delete the session on the UP through the Control Interface. 8. Event reports include the following two parts (more detail can be found in Section 4.3.4). Both are reported using the Event message. 1. Subscriber Traffic Statistics Report 2. Subscriber Detection Result Report 9. Data synchronization: See Sections 4.2.5 for more detail on CP and UP Synchronization. 10. CGN address allocation: See Sections 4.2.4 for more detail on CGN Address Allocation. 4. S-CUSP Protocol Overview 4.1. Control Channel Related Procedures 4.1.1. S-CUSP Session Establishment A UP is associated with a CP and is controlled by that CP. In the case of a hot-standby or warm-standby, a UP is associated with two CPs, one called the Master CP and the other called the Standby CP. The association between a UP and its CP(s) is implemented by configuration. Hu, et al. Expires November 24, 2019 [Page 14] Internet-Draft S-CUSP for BNG May 2019 Once a UP knows its CP(s), the UP starts to establish S-CUSP session(s) with those CP(s) as shown below. UP CP | | | TCP Session Establishment | |<------------------------------->| | | | HELLO (version, capability) | |-------------------------------->| | | | HELLO (version, capability) | |<--------------------------------| | | Figure 4.1.1: S-CUSP Session Establishment The S-CUSP session establishment consists of two successive steps: 1. Establishment of a TCP [RFC793] connection (3-way handshake) between the CP and the UP using port tbd1. 2. Establishment of a S-CUSP session over the TCP connection. Once the TCP connection is established, the CP and the UP initialize the S-CUSP session during which the version negotiation and Keepalive timers negotiation are performed. The version information (Hello TLV, see section 7.4) is carried within Hello messages (see Section 6.2.1). A CP can support multiple versions, but a UP can only support one version. So, the version negotiation is based on whether a version can be support by both the CP and the UP. For a CP or UP, if received a Hello message that does not have a supported version, the next Hello message with an Error Information TLV will be sent to its peer to notify the "Version- Mismatch" error . Then session establishment phase fails. Keepalive negotiation is performed by carrying a Keepalive TLV in the Hello message. The Keepalive TLV carries a Keepalive timer and Dead Timer. Both the CP and UP have to agree on the Keepalive Timer and Dead Timer. Otherwise, a Hello message with an Error Information TLV will be sent to its peer. Then session establishment phase fails. The S-CUSP session establishment phase fails if the CP or UP disagree on the version and Keepalive parameters or one of the CP or UP does not answer after the expiration of the establishment timer. When the S-CUSP session establishment fails, the TCP connection is promptly closed. Hu, et al. Expires November 24, 2019 [Page 15] Internet-Draft S-CUSP for BNG May 2019 4.1.2. Keep Alive Once an S-CUSP session has been established, a UP or CP may want to know that its S-CUSP peer is still available for use. Each end of a S-CUSP session runs a Keepalive timer. It restarts the timer every time it sends a message on the session. When the timer expires, it sends a Keepalive message. The ends of the S-CUSP session also run DeadTimers that they restart whenever a message is received on the session. If one end of the session receives no message after the DeadTimer expires, it declares the session dead. The session is closed. The minimum value of the Keepalive timer is 1 second, and it is specified in units of 1 second. The recommended default value is 30 seconds. The timer may be disabled by setting it to zero. The recommended default for the DeadTimer is 4 times the value of the Keepalive timer used by the remote peer. This implies there is essentially no risk of TCP congestion due to excessive Keepalive messages. The Keepalive timer and DeadTimer are initially negotiated through the Keepalive TLV carried in the Hello Message. 4.2. Node Related Procedures 4.2.1. UP Board and Interface Status Report Once an S-CUSP session has been established between a CP and a UP. The UP reports the information about the Board(s) and access side interface(s) on this UP to the CP. The CP can use that information to activate/enable the Broadband Access Service (BAS) functions (e.g., IPoE, PPPoE, etc.) on the specified interface(s). In addition, the UP resource report may trigger a UP warm-standby procedure. In the case of warm-standby, a failure on a UP may trigger the CP to start the warm-standby procedure, by moving the on- line subscriber sessions to a standby UP and then directing the affected subscribers to access the Internet through the standby UP. Hu, et al. Expires November 24, 2019 [Page 16] Internet-Draft S-CUSP for BNG May 2019 UP CP | | | Report Board Status | |------to CP via Ci----->| | | | Report Interface Status| |------to CP via Ci----->| | | Figure 4.2.1: UP Board and Interface Report Board status information is carried in the Board Status TLV(Section 7.10.2), interface status information is carried in the Interface Status TLV (Section 7.10.1). Both Board and Interface Status TLVs are carried in the Report message (Section 6.4). 4.2.2. Enable BAS Function on Access Interface Once the CP collects the interface status of a UP, it will activate/ enable the BAS functions on specified interfaces through the Update_Request and Update_Response message (Section 6.2) exchanges carrying the BAS Function Enabler TLV (Section 7.7). UP CP | | | Enable BAS function | | Request | |<-----on UP via Ci-------| | | | Enable BAS function | | Response | |------on UP via Ci------>| | | Figure 4.2.2: Enable BAS Functions 4.2.3. Advertise Subscriber Network Routing The CP will allocate one or more address blocks to a UP. Each address block contains a series of IP addresses. Those IP addresses will be allocated to subscribers who are dialing up to the UP. To enable other nodes in the network to learn how to reach the subscribers, the CP needs to install the routes on the UP and notify the UP to advertise the routes to the network. Hu, et al. Expires November 24, 2019 [Page 17] Internet-Draft S-CUSP for BNG May 2019 UP CP | | | Subscriber network route| | advertisement request | |<------- via Ci----------| | | | Subscriber network route| | advertisement response | |-------- via Ci--------->| | | Figure 4.2.3: Advertise Subscriber Network Routing The subscriber network route advertisement request and response are achieved through the Update_Request and Update_Response Messages exchanges by carrying the IPv4/IPv6 Routing TLVs (Section 7.8). 4.2.4. CGN Public IP Address Allocation The following sequences describe the CGN address management related procedures. Three independent procedures are defined. The relevant messages are defined in Section 6.5. UP CP | | | CGN Address Allocation | | Request | 1.1|-------- via Ci--------->| | CGN Address Allocation | | Response | 1.2|<------- via Ci----------| | | | CGN Address Renew | | Request | 2.1|-------- via Ci--------->| | CGN Address Renew | | Response | 2.2|<------- via Ci----------| | | | CGN Address Release | | Request | 3.1|-------- via Ci--------->| | CGN Address Release | | Response | 3.3|<------- via Ci----------| | | Figure 4.2.4: CGN Public IP Address Allocation Hu, et al. Expires November 24, 2019 [Page 18] Internet-Draft S-CUSP for BNG May 2019 4.2.5. Data Synchronization Between CP and UP Under some circumstances it is necessary to synchronize state between the CP and UP, for example if a CP fails and the UP is switched to a different CP. Synchronization includes two directions. One direction is from UP to CP, the synchronization information is mainly about the board/ interface status of the UP. The other direction is from CP to UP, the subscriber sessions, subscriber network routes, L2TP tunnels, etc. will be synchronized to the UP. The synchronization is triggered by a Synch_Request message, the receiver will reply with a Sync_Begin message to notify the requester that synchronization will begin, then start the synchronization through one or more Sync_Data messages. When synchronization finishes, a Sync_End message is sent. The following figure shows the process of data synchronization between a UP and a CP. Hu, et al. Expires November 24, 2019 [Page 19] Internet-Draft S-CUSP for BNG May 2019 UP CP | | | Synchronization Request | |<------- via Ci----------| | | | Synchronization Begin | |-------- via Ci--------->| | | | Board/Interface Report | |-------- via Ci--------->| | | | Synchronization End | |-------- via Ci--------->| | | 1) Synchronization from UP to CP UP CP | | | Synchronization Request | |-------- via Ci--------->| | | | Synchronization Begin | |<-------- via Ci---------| | | | Synchronizes Sessions | | /Routes/Tunnels... | |<------- via Ci----------| | | | Synchronization End | |<-------- via Ci---------| | | 2) Synchronization from CP to UP Figure 4.2.5: Data Synchronization 4.3. Subscriber Session Related Procedures A subscriber session consists of a set of forwarding states, policies, and security rules that are required to apply to the subscriber. It is used for forwarding subscriber traffic on a UP. To initialize a session on a UP, a set of hardware resource have to be allocated (e.g. NP, TCAM etc.) to a session. Subscriber session related procedures include subscriber session create, update, delete and statistics report. The following sub- sections give a high view about the procedures. Hu, et al. Expires November 24, 2019 [Page 20] Internet-Draft S-CUSP for BNG May 2019 4.3.1. Create Subscriber Session The below sequence describes the DHCP IPv4 dial-up process, it gives an example that shows how a subscriber session is created. RG UP CP AAA | | | | | DHCP Discovery| | | 1|-------------->| | | | |Relay the DHCP Discovery| | | 2|-----to CP via Si------>| Authentication| | | | Req/Rep | | | 3|<------------->| | | | | | | Send the DHCP Offer | | | 4|<----to UP vis Si-------| | | DHCP Offer | | | 5|<--------------| | | | | | | | DHCP Request | | | 6|-------------->| | | | | Relay the DHCP Request| | | 7|-----to CP via Si------>| | | | | | | | Create subscriber | | | | session Request | | | 8|<--------via Ci-------->| | | | | | | | Create subscriber | | | | session Response | | | 9|---------via Ci-------->| | | | | | | | | Accounting | | | 10|<------------->| | | | | | | Send DHCP ACK | | | 11|<----to UP via Si-------| | | | | | | DHCP ACK | | | 12|<--------------| | | | | | | Figure 4.3.1: Subscriber Session Create The request starts from a DHCP Discovery message from the RG. When the UP receives the DHCP Discovery from the RG, it will tunnel the DHCP Discovery to the CP through the Service Interface. The Service Interface is implemented by a tunnel technology. Hu, et al. Expires November 24, 2019 [Page 21] Internet-Draft S-CUSP for BNG May 2019 When the CP receives the DHCP Discovery from the UP, it will send an authentication request to the AAA server to authenticate and authorize the subscriber. When a positive return from the AAA sever received, the CP will send a DHCP Offer message to the UP through the Service Interface. The UP will then forward the DHCP Offer to the RG. After received the DHCP Offer, the RG will send a DHCP Request to the UP. As when dealing with the DHCP Discovery message, the UP will tunnel the DHCP Request to the CP. The CP starts to create a subscriber session for the request. Relevant resource (e.g., IP address, bandwidth, etc.) will be allocated to the subscriber and policies and security rules will be generated for the subscriber. Then the CP sends a session create request to the UP through the Control Interface (Ci), and a response is expected from the UP to confirm the creation. Finally, the CP will notify the AAA server to start accounting. At the same time, a DHCP ACK message will be sent to the UP through the Si. And the UP will forward the DHCP ACK to the RG. This completes the whole dial-up process. 4.3.2. Update Subscriber Session The following numbered sequence describes the process of subscriber session update. UP CP AAA | | COA Request | | 1|<--------------| | Session update Request | | 2|<--------via Ci---------| | | | | | Session update Response| | 3|---------via Ci-------->| | | | COA Response | | 4|-------------->| | | | Figure 4.3.2: Subscriber Session Update When a subscriber session has been created on a UP, there may be requirements to update the session with new parameters (e.g., Bandwidth, QoS, policies, etc.). This procedure is triggered by a Change of Authorization (COA) request message sent by the AAA server. The CP will update the Hu, et al. Expires November 24, 2019 [Page 22] Internet-Draft S-CUSP for BNG May 2019 session on the UP according to the new parameters through the Control Interface. 4.3.3. Delete Subscriber Session The below call flow shows a general process for how BNG CUPS deals with the subscriber offline request. RG UP CP | | | |Offline Request | | 1|--------------->| | | | Relay the Offline | | | Request | | 2|------to CP via Si----->| | | | | | Send the Offline | | | Response | | 3|<-----to UP via Si------| |Offline Response| | 4|<---------------| | | | Session delete | | |<--------via Ci-------->| | | | Figure 4.3.3: Subscriber Session Delete Similar to the session creation process, when a UP receives an offline request from an RG, it will tunnel the request to a CP through the Si. When the CP receives the offline request, it will withdraw/release the resource (e.g., IP address, bandwidth) that has been allocated to the subscriber. And then, it may send a response to the UP through the Service Interface, the UP will forward the response to the RG. At the same time, it will delete all the status of the session on the UP through the Ci. 4.3.4. Subscriber Session Events Report UP CP | | | Statistic/Detect report| |---------via Ci-------->| | | Hu, et al. Expires November 24, 2019 [Page 23] Internet-Draft S-CUSP for BNG May 2019 When a subscriber session is created on a UP, the UP will periodically report statistics and detection results of the session to the CP. 5. S-CUSP Call Flows The subsections below give an overview of various "dial-up" interactions over the Service Interface followed by the setting of various information on the UP by the CP using S-CUSP over the Control Interface. 5.1. IPoE 5.1.1. DHCPv4 Access The following sequence gives detailed procedures for DHCPv4 access. Hu, et al. Expires November 24, 2019 [Page 24] Internet-Draft S-CUSP for BNG May 2019 RG UP CP AAA | | | | | DHCP Discovery| | | 1|-------------->| | | | |Relay the DHCP Discovery| | | 2|-----to CP via Si------>| AAA | | | | Req/Rep | | | 3|<------------->| | | | | | | Send the DHCP Offer | | | 4|<----to UP vis Si-------| | | DHCP Offer | | | 5|<--------------| | | | DHCP Request | | | 6|-------------->| | | | | Relay the DHCP Request| | | 7|-----to CP via Si------>| | | | | | | | Create subscriber | | | | session Request | | | 8|<---------via Ci--------| | | | Create subscriber | | | | session Response | | | 9|---------via Ci-------->| | | | | Accounting | | | 10|<------------->| | | | | | | Send DHCP ACK | | | 11|<----to UP via Si-------| | | | | | | DHCP ACK | | | 12|<--------------| | | | | | | Figure 5.1.1: DHCPv4 Access Step 8 and 9 are implemented by the S-CUSP protocol. When a subscriber is authenticated and authorized by the AAA server, the CP will create a subscriber session on the UP. This is achieved by sending a UPdate_Request message to the UP. The format of the Update_Request message is as follows: Hu, et al. Expires November 24, 2019 [Page 25] Internet-Draft S-CUSP for BNG May 2019 ::= [] The UP will reply with an Update_Response message, the format of the Update_Response is as follows: ::= [] 5.1.2. DHCPv6 Access The following sequence gives detailed procedures for DHCPv6 access. Hu, et al. Expires November 24, 2019 [Page 26] Internet-Draft S-CUSP for BNG May 2019 RG UP CP AAA | | | | | Solicit | | | 1|-------------->| | | | | Relay the Solicit | | | 2|-----to CP via Si------>| AAA | | | | Req/Rep | | | 3|<------------->| | | | | | | Send the Advertise | | | 4|<----to UP vis Si-------| | | Advertise | | | 5|<--------------| | | | | | | | Request | | | 6|-------------->| | | | | Relay the Request | | | 7|-----to CP via Si------>| | | | | | | | | | | | Create subscriber | | | | session Request | | | 8|<--------via Ci-------->| | | | | | | | Create subscriber | | | | session Response | | | 9|---------via Ci-------->| | | | | | | | | Accounting | | | 10|<------------->| | | | | | | Send Reply | | | 11|<----to UP via Si-------| | | | | | | Reply | | | 12|<--------------| | | | | | | Figure 5.1.2: DHCPv6 Access Steps 1-7 are a standard DHCP IPv6 access process. The subscriber creation is triggered by a DHCP IPv6 request message. This message means that the subscriber has passed the AAA authentication and authorization. Then the CP will create a subscriber session on the UP. This is achieved by sending a UPdate_Request message to the UP (Step 8). The format of the Update_Request message is as follows: Hu, et al. Expires November 24, 2019 [Page 27] Internet-Draft S-CUSP for BNG May 2019 ::= [] The UP will reply with an Update_Response message (Step 9), the format of the Update_Response is as follows: ::= 5.1.3. IPv6 SLAAC Access The following flow describes the IPv6 SLAAC access process. Hu, et al. Expires November 24, 2019 [Page 28] Internet-Draft S-CUSP for BNG May 2019 RG UP CP AAA | | | | | RS | | | 1|-------------->| | | | | Relay the Router | | | | Solicit (RS) | | | 2|-----to CP via Si------>| AAA | | | | Req/Rep | | | 3|<------------->| | | | | | | Create subscriber | | | | session Request | | | 4|<--------via Ci---------| | | | | | | | Create subscriber | | | | session Response | | | 5|---------via Ci-------->| | | | | | | | Send Router Advertise | | | | (RA) | | | 6|<----to UP vis Si-------| | | RA | | | 7|<--------------| | | | | | | | NS | | | 8|-------------->| | | | | Relay the Neighbor | | | | Solicit (NS) | | | 9|-----to CP via Si------>| | | | | | | | | Accounting | | | 10|<------------->| | | | | | | Send a Neighbor | | | | Advertise (NA) | | | 11|<----to UP via Si-------| | | | | | | NA | | | 12|<--------------| | | | | | | Figure 5.1.3: IPv6 SLAAC Access It starts with a Router Solicit (RS) request from an RG, it will be tunneled to the CP when the UP receives the message. After the AAA authentication and authorization, the CP will create a subscriber session on the UP. This is achieved by sending a UPdate_Request message to the UP (step 4). Hu, et al. Expires November 24, 2019 [Page 29] Internet-Draft S-CUSP for BNG May 2019 The format of the Update_Request message is as follows: ::= [] The UP will reply with an Update_Response message (step 5). The format of the Update_Response is as follows: ::= 5.1.4. DHCPv6 + SLAAC Access The following call flow describes the DHCP IPv6 and SLAAC access process. Hu, et al. Expires November 24, 2019 [Page 30] Internet-Draft S-CUSP for BNG May 2019 RG UP CP AAA | | | | | RS | | | 1|-------------->| | | | | Relay the Router | | | | Solicit (RA) | | | 2|-----to CP via Si------>| AAA | | | | Req/Rep | | | 3|<------------->| | | | | | | Create subscriber | | | | session Request | | | 4|<--------via Ci---------| | | | | | | | Create subscriber | | | | session Response | | | 5|---------via Ci-------->| | | | | | | | Send Router Advertise | | | | (RA) | | | 6|<----to UP vis Si-------| | | RA | | | 7|<--------------| | | | | | | |DHCPv6 Solicit | | | 8|-------------->| | | | | Relay DHCPv6 Solicit | | | 9|-----to CP via Si------>| | | | | | | | Update subscriber | | | | session Request | | | 10|<--------via Ci---------| | | | | | | | Update subscriber | | | | session Response | | | 11|---------via Ci-------->| | | | | | | | | Accounting | | | 12|<------------->| | | | | | | Send DHCPv6 Reply | | | 13|<----to UP via Si-------| | | | | | | DHCPv6 Reply | | | 14|<--------------| | | | | | | Figure 5.1.4: DHCPv6 + SLAAC Access Hu, et al. Expires November 24, 2019 [Page 31] Internet-Draft S-CUSP for BNG May 2019 When a subscriber passed AAA authentication, the CP will create a subscriber session on the UP. This is achieved by sending a UPdate_Request message to the UP (step 4). ::= [] The UP will reply with an Update_Response message (step 5). The format of the Update_Response is as follows: ::= After receiving a DHCPv6 Solicit, the CP will update the subscriber session by sending a UPdate_Request message with new parameters to the UP (Step 10). The format of the Update_Request message is as follows: ::= [] The UP will reply with an Update_Response message (step 11). The format of the Update_Response is as follows: ::= 5.1.5. DHCP Dual Stack Access The following sequence is a combination of DHCP IPv4 and DHCP IPv6 access process. RG UP CP AAA | | | | | DHCP Discovery| | | 1|-------------->| | | | |Relay the DHCP Discovery| | | 2|-----to CP via Si------>| AAA | | | | Req/Rep | | | 3|<------------->| | | | | Hu, et al. Expires November 24, 2019 [Page 32] Internet-Draft S-CUSP for BNG May 2019 | | Send the DHCP Offer | | | 4|<----to UP vis Si-------| | | DHCP Offer | | | 5|<--------------| | | | DHCP Request | | | 6|-------------->| | | | | Relay the DHCP Request| | | 7|-----to CP via Si------>| | | | | | | | Create subscriber | | | | session Request | | | 8|<--------via Ci-------->| | | | Create subscriber | | | | session Response | | | 9|---------via Ci-------->| | | | | Accounting | | | 10|<------------->| | | Send DHCP ACK | | | 11|<----to UP via Si-------| | | | | | | DHCP ACK | | | 12|<--------------| | | | RS | | | 13|-------------->| | | | | Relay the Router | | | | Solicit (RA) | | | 14|-----to CP via Si------>| | | | | Accounting | | | 15|<------------->| | | | | | | Update subscriber | | | | session Request | | | 16|<--------via Ci---------| | | | Update subscriber | | | | session Response | | | 17|---------via Ci-------->| | | | | | | | Send Router Advertise | | | | (RA) | | | 18|<----to UP vis Si-------| | | RA | | | 19|<--------------| | | | | | | |DHCPv6 Solicit | | | 20|-------------->| | | | | Relay DHCPv6 Solicit | | | 21|-----to CP via Si------>| | | | | | Hu, et al. Expires November 24, 2019 [Page 33] Internet-Draft S-CUSP for BNG May 2019 | | Update subscriber | | | | session Request | | | 22|<--------via Ci---------| | | | Update subscriber | | | | session Response | | | 23|---------via Ci-------->| | | | | Accounting | | | 24|<------------->| | | Send DHCPv6 Reply | | | 25|<----to UP via Si-------| | | DHCPv6 Reply | | | 26|<--------------| | | | | | | Figure 5.1.5: DHCP Dual Stack Access The DHCP dual stack access includes three Update_Request/ Update_Response message exchanges to create/update DHCPv4/v6 subscriber session. 1. Create DHCPv4 session (step 8 and 9) ::= [] ::= [] 2. Create or Update? DHCPv6 session (step 16 and 17) ::= [] ::= 3. Update DHCPv6 session (step 22 and 23) Hu, et al. Expires November 24, 2019 [Page 34] Internet-Draft S-CUSP for BNG May 2019 ::= [] ::= 5.1.6. L2 Static Subscriber Access L2 static subscriber access processes are as follows: RG UP CP AAA | | | | | |Static Subscriber Access| | | | Control List Req. | | | 1|<-----to UP via Ci------| | | |Static Subscriber Access| | | | Control List Rep. | | | 2|------to CP via Ci----->| | | ARP/ND(REQ) | | | 3.1|<--------------| | | | ARP/ND(ACK) | | | 3.2|-------------->| | | | | Relay the ARP/ND | | | 3.3|-----to CP via Si------>| AAA | | | | Req/Rep | | | 3.4|<------------->| | | Create subscriber | | | | session Request | | | 3.5|<--------via Ci---------| | | | Create subscriber | | | | session Response | | | 3.6|---------via Ci-------->| | | | | | | ARP/ND(REQ) | | | 4.1|-------------->| | | | | Relay the ARP/ND | | | 4.2|-----to CP via Si------>| AAA | | | | Req/Rep | | | 4.3|<------------->| | | Create subscriber | | | | session Request | | | 4.4|<--------via Ci-------->| | | | Create subscriber | | | | session Response | | | 4.5|---------via Ci-------->| | Hu, et al. Expires November 24, 2019 [Page 35] Internet-Draft S-CUSP for BNG May 2019 | ARP/ND(ACK) | | | 4.6|<--------------| | | | | | | | IP Traffic | | | 5.1|-------------->| | | | | Relay the IP Traffic | | | 5.2|-----to CP via Si------>| AAA | | | | Req/Rep | | | 5.3|<------------->| | | Create subscriber | | | | session Request | | | 5.4|<--------via Ci---------| | | | Create subscriber | | | | session Response | | | 5.5|---------via Ci-------->| | | | | | | ARP/ND(REQ) | | | 5.6|<--------------| | | | ARP/ND(ACK) | | | 5.7|-------------->| | | | | | | Figure 5.1.6: L2 Static Subscriber Access For L2 static subscriber access, it always starts with a CP installing a subscriber access control list on a UP. The subscriber access control list is used by the UP to determine whether an RG is allowed to access the network. This is implemented by exchanging Update_Request and Update_Response messages between CP and UP. The format of the messages are as follows: ::= ::= For L2 Static Subscriber Access, there are three ways to trigger the access process: 1. Triggered by UP (3.1-3.6): This assumes that the UP knows the IP address, the access interface, and VLAN of the RG. The UP will actively trigger the access flow by sending an ARP/ND packet to the RG. If the RG is online, it will reply with an ARP/ND response to the UP. The UP will tunnel the ARP/ND to the CP through the Si. It will then trigger the authentication process. If the authentication result is positive. The CP will create a corresponding subscriber session on the UP. Hu, et al. Expires November 24, 2019 [Page 36] Internet-Draft S-CUSP for BNG May 2019 2. Triggered by RG ARP/ND (4.1-4.6): Most of the process is same as option 1 (triggered by UP). The difference is that the RG will actively send the ARP/ND to trigger the process. 3. Triggered by RG IP traffic (5.1-5.7): This is for the case where the RG has the ARP/ND entity, but the subscriber session on the UP is lost (e.g., due to failure on the UP, or the UP restarted). That means the RG may keep sending IP packets to the UP. The packets will trigger the UP to start a new access process. From a subscriber session point of view, the procedures and the message formats for the above three cases are the same, as follows: IPv4 Case: ::= [] ::= [] IPv6 Case: ::= [] ::= 5.2. PPPoE 5.2.1. IPv4 PPPoE Access The following figure describes the IPv4 PPPoE access call flow. Hu, et al. Expires November 24, 2019 [Page 37] Internet-Draft S-CUSP for BNG May 2019 RG UP CP AAA | | | | | PPPoE Disc | PPPoE Disc | | 1|<------------->|<---------via Si------->| | | | | | | PPP LCP | PPP LCP | | 2|<------------->|<---------via Si------->| | | | | AAA | | PPP PAP/CHAP | PPP PAP/CHAP | Req/Rep | 3|<------------->|<---------via Si------->|<------------->| | | | | | PPP IPCP | PPP IPCP | | 4|<------------->|<---------via Si------->| | | | | | | | Create subscriber | | | | session Request | | | 5|<--------via Ci---------| | | | | | | | Create subscriber | | | | session Response | | | 6|---------via Ci-------->| | | | | | | | | Accounting | | | 7|<------------->| | | | | Figure 5.2.1: IPv4 PPPoE Access From the above sequence, steps 1-4 are the standard PPPoE call flow. The UP is responsible for redirecting the PPPoE control packets to the CP or RG. The PPPoE control packets are transmitted between the CP and UP through the Si. After the PPPoE call flow, if the subscriber passed the AAA authentication and authorization, the CP will create a corresponding session on the UP through the Ci. The formats of the messages are as follows: ::= [] ::= [] Hu, et al. Expires November 24, 2019 [Page 38] Internet-Draft S-CUSP for BNG May 2019 5.2.2. IPv6 PPPoE Access The following figure describes the IPv6 PPPoE access call flow. RG UP CP AAA | | | | | PPPoE Disc | PPPoE Disc | | 1|<------------->|<--------via Si-------->| | | | | | | PPP LCP | PPP LCP | | 2|<------------->|<---------via Si------->| | | | | AAA | | PPP PAP/CHAP | PPP PAP/CHAP | Req/Rep | 3|<------------->|<---------via Si------->|<------------->| | | | | | PPP IP6CP | PPP IP6CP | | 4|<------------->|<---------via Si------->| | | | | | | | Create subscriber | | | | session Request | | | 5|<---------via Ci--------| | | | | | | | Create subscriber | | | | session Response | | | 6|---------via Ci-------->| | | | | | | ND Negotiation| ND Negotiation | | 7|<------------->|<---------via Si------->| | | | | | | | Update subscriber | | | | session Request | | | 8|<---------via Ci--------| | | | | | | | Update subscriber | | | | session Response | | | 9|---------via Ci-------->| | | | | | | | | Accounting | | | 10|<------------->| | | | | | DHCPv6 | DHCPv6 | | | Negotiation | Negotiation | | 7'|<------------->|<---------via Si------->| | | | | | | | Update subscriber | | | | session Request | | | 8'|<--------via Ci---------| | | | | | Hu, et al. Expires November 24, 2019 [Page 39] Internet-Draft S-CUSP for BNG May 2019 | | Update subscriber | | | | session Response | | | 9'|---------via Ci-------->| | | | | | | | | Accounting | | | 10'|<------------->| | | | | Figure 5.2.2: IPv6 PPPoE Access From the above sequence, steps 1-4 are the standard PPPoE call flow. The UP is responsible for redirecting the PPPoE control packets to the CP or RG. The PPPoE control packets are transmitted between the CP and UP through the Si. After the PPPoE call flow, if the subscriber passed AAA authentication and authorization, the CP will create a corresponding session on the UP through the Ci. The formats of the messages are as follows: ::= [] ::= Then, the RG will initialize a ND/DHCPv6 negotiation process with the CP (see step 7 and 7'), after then, it will trigger an update (8-9, 8'-9') to the subscriber session, the formats of the update messages are as follows: ::= [] ::= Hu, et al. Expires November 24, 2019 [Page 40] Internet-Draft S-CUSP for BNG May 2019 5.2.3. PPPoE Dual Stack Access The following figure describes a combination of IPv4 and IPv6 PPPoE access call flow. RG UP CP AAA | | | | |PPPoE Discovery| PPPoE Discovery | | 1|<------------->|<---------via Si------->| | | | | | | PPP LCP | PPP LCP | | 2|<------------->|<---------via Si------->| | | | | AAA | | PPP PAP/CHAP | PPP PAP/CHAP | Req/Rep | 3|<------------->|<---------via Si------->|<------------->| | | | | | PPP IPCP | PPP IPCP | | 4|<------------->|<---------via Si------->| | | | | | | | Create v4 subscriber | | | | session Request | | | 5|<--------via Ci---------| | | | Create v4 subscriber | | | | session Response | | | 6|---------via Ci-------->| | | | | Accounting | | | 7|<------------->| | PPP IP6CP | PPP IP6CP | | 4'|<------------->|<---------via Si------->| | | | | | | | Create V6 subscriber | | | | session Request | | | 5'|<--------via Ci---------| | | | Create v6 subscriber | | | | session Response | | | 6'|---------via Ci-------->| | | | | | | ND Negotiation| ND Negotiation | | 8|<------------->|<---------via Si------->| | | | | | | | Update v6 subscriber | | | | session Request | | | 9|<---------via Ci--------| | | | Update v6 subscriber | | | | session Response | | | 10|---------via Ci-------->| | | | | Accounting | | | 7'|<------------->| Hu, et al. Expires November 24, 2019 [Page 41] Internet-Draft S-CUSP for BNG May 2019 | DHCPv6 | DHCPv6 | | | Negotiation | Negotiation | | 8'|<------------->|<---------via Si------->| | | | | | | | Update v6 subscriber | | | | session Request | | | 9'|<---------via Ci--------| | | | | | | | Update v6 subscriber | | | | session Response | | | 10'|---------via Ci-------->| | | | | Accounting | | | 7"|<------------->| | | | | Figure 5.2.3: PPPoE Dual Stack Access PPPoE dual stack is a combination of IPv4 PPPoE and IPv6 PPPoE access. The process is as above. The formats of the messages are as follows: 1. Create an IPv4 PPPoE subscriber session (5-6) ::= [] ::= [] 2. Create an IPv6 PPPoE subscriber session (5'-6') ::= [] ::= 3. Update the IPv6 PPPoE subscriber session (9-10, 9'-10') Hu, et al. Expires November 24, 2019 [Page 42] Internet-Draft S-CUSP for BNG May 2019 ::= [] ::= 5.3. WLAN Access The following figure describes the WLAN access call flow. RG UP CP AAA WEB Server | | | | | | DHCP | | | | | Discovery | | | | 1|------------>| | | | | | DHCP | | | | | Discovery | | | | 2|-----via Si---->| AAA | | | | DHCP Offer |<-------->| | | 3|<----via Si-----| | | | DHCP Offer | | | | 4|<------------| | | | | DHCP | | | | | Request | | | | 5|------------>| | | | | | DHCP Request | | | | 6|-----via Si---->| | | | | | | | | | Create session | | | | | Request | | | | 7|<----via Ci-----| | | | | Create session | | | | | Response | | | | 8|----via Ci----->| | | | | | | | | | DHCP ACK | | | | 9|<----via Si-----| | | | | | | | | DHCP ACK | | | | 10|<------------| | | | | | | | | | Subscriber | | | | | HTTP Traffic| | | | 11|------------>|--> | | | Hu, et al. Expires November 24, 2019 [Page 43] Internet-Draft S-CUSP for BNG May 2019 | | | WEB URL | | | | Traffic | | Redirect | | | | Redirection | | | | | 12|<------------|<-+ | | | | | | | | | 13|-----------------Redirect to Web server------------->| | | 14|<----------------Push HTTP log-in page---------------| | | 15|-----------------User Authentication---------------->| | | | | | Portal Interchange | | | 16|<-------------------->| | | | | | | | AAA | | | | | Req/Rep | | | | 17|<-------->| | | | | | | | | Update session | | | | | Request | | | | 18|<----via Ci-----| | | | | | | | | | Update session | | | | | Response | | | | 19|-----via Ci---->| | | | | | | | Figure 5.3: WLAN Access WLAN access starts with the DHCP dial-up process (steps 1-6), after that the CP will create a subscriber session on the UP (step 7-8). The formats of the session creation messages are as follows: Hu, et al. Expires November 24, 2019 [Page 44] Internet-Draft S-CUSP for BNG May 2019 IPv4 Case: ::= [] ::= [] IPv6 Case: ::= [] ::= After step 10, the RG will be allocated an IP address and its first HTTP packet will be redirected to a WEB server for subscriber authentication (step 11-17). After the WEB authentication, if the result is positive, the CP will update the subscriber session by using the following message exchanges: IPv4 Case: ::= [] ::= [] IPv6 Case: ::= [] ::= Hu, et al. Expires November 24, 2019 [Page 45] Internet-Draft S-CUSP for BNG May 2019 5.4. L2TP 5.4.1. L2TP LAC Access RG UP(LAC) CP(LAC) AAA LNS | | | | | | PPPoE | PPPoE | | | | Discovery | Discovery | | | 1|<---------->|<---via Si--->| | | | | | | | | PPP LCP | PPP LCP | | | 2|<---------->|<---via Si--->| | | | | | AAA | | |PPP PAP/CHAP| PPP PAP/CHAP | Req/Rep| | 3|<---------->|<---via Si--->|<------>| | | | | | | | PPP IPCP | PPP IPCP | | | 4|<---------->|<---via Si--->| | | | | | | | | | L2TP tunnel | | | | | negotiation | | | | | SCCRQ/ | | | | | SCCRP/ | | | | | SCCCN | | | | 5|<---via Si--->| | | | | /\ | | | || forward | | | \/ | | |<-----------via routing---------->| | | | | | L2TP session | | | | | negotiation | | | | | ICRQ/ | | | | | ICRP/ | | | | | ICCN | | | | 6|<---via Si--->| | | | | /\ | | | || forward | | | \/ | | |<-----------via routing---------->| | | | | | Create | | | | | subscriber | | | | | session | | | | | Request | | | | 7|<---via Ci----| | | | | | | | | | Create | | | Hu, et al. Expires November 24, 2019 [Page 46] Internet-Draft S-CUSP for BNG May 2019 | | subscriber | | | | | session | | | | | Response | | | | 8|----via Ci--->| | | | | | | | | | | PAP/CHAP (Triggered by LNS) | 9|<-----------------via routing?---------------->| | | Figure 5.4.1: L2TP-LAC Access Steps 1-4 are a standard PPPoE access process. After that the LAC-CP starts to negotiate a L2TP session and tunnel with the LNS. After the negotiation, the CP will create a L2TP LAC subscriber session on the UP through the following messages: ::= ::= 5.4.2. L2TP LNS IPv4 Access RG LAC UP(LNS) AAA CP(LNS) | | | | | | PPPoE | | | | | Discovery | | | | 1|<---------->| | | | | | | | | | PPP LCP | | | | 2|<---------->| | | | | AAA | | |PPP PAP/CHAP| Req/Rep | | 3|<---------->|<--------------------->| | | | | | | | | | L2TP tunnel | L2TP tunnel | | | negotiation | negotiation | | | SCCRQ/ | SCCRQ/ | | | SCCRP/ | SCCRP/ | | | SCCCN | SCCCN | | 4|<------------>|<------via Si----->| | | | | Hu, et al. Expires November 24, 2019 [Page 47] Internet-Draft S-CUSP for BNG May 2019 | | L2TP session | L2TP session | | | negotiation | negotiation | | | ICRQ/ | ICRQ/ | | | ICRP/ | ICRP/ | | | ICCN | ICCN | | 5|<------------>|<------via Si----->| | | | | | | | Create | | | | subscriber | | | | session | | | | Request | | | 6|<-----via Ci-------| | | | Create | | | | subscriber | | | | session | | | | Response | | | 7|------via Ci------>| | | | PAP/CHAP (Triggered by LNS) | 8|<--------------------------------------------->| | | | | | | AAA | | | | | Req/Rep | | | | 9|<-------->| | | | | | | | PPP IPCP | 10|<--------------------------------------------->| | | | | | Update | | | | subscriber | | | | session | | | | Request | | | 11|<-----via Ci-------| | | | Update | | | | subscriber | | | | session | | | | Response | | | 12|------via Ci------>| | | | | Figure 5.4.2: IPv4 L2TP-LNS Access In this case, the BNG is running as an LNS and separated into LNS-CP and LNS-UP. Step 1-5 finish the normal L2TP dial-up process. When the L2TP session and tunnel negotiations are finished, the LNS-CP will create a L2TP LNS subscriber session on the LNS-UP. The format of messages are as follows: Hu, et al. Expires November 24, 2019 [Page 48] Internet-Draft S-CUSP for BNG May 2019 ::= [] ::= [] After then, the LNS-CP will trigger a AAA authentication, if the authentication result is positive. A PPP IPCP process will follow, then the CP will update the session with the following message exchanges: ::= [] ::= [] 5.4.3. L2TP LNS IPv6 Access RG LAC UP(LNS) AAA CP(LNS) | | | | | | PPPoE | | | | | Discovery | | | | 1|<---------->| | | | | | | | | | PPP LCP | | | | 2|<---------->| | | | | AAA | | |PPP PAP/CHAP| Req/Rep | | 3|<---------->|<--------------------->| | | | | | | | | | L2TP tunnel | L2TP tunnel | | | negotiation | negotiation | Hu, et al. Expires November 24, 2019 [Page 49] Internet-Draft S-CUSP for BNG May 2019 | | SCCRQ/ | SCCRQ/ | | | SCCRP/ | SCCRP/ | | | SCCCN | SCCCN | | 4|<------------>|<------via Si----->| | | | | | | L2TP session | L2TP session | | | negotiation | negotiation | | | ICRQ/ | ICRQ/ | | | ICRP/ | ICRP/ | | | ICCN | ICCN | | 5|<------------>|<------via Si----->| | | | | | | | Create | | | | subscriber | | | | session | | | | Request | | | 6|<-----via Ci-------| | | | Create | | | | subscriber | | | | session | | | | Response | | | 7|------via Ci------>| | | | PAP/CHAP (Triggered by LNS) | 8|<--------------------------------------------->| | | | | | | AAA | | | | | Req/Rep | | | | 9|<-------->| | | | | | | | | PPP IP6CP | 10|<--------------------------------------------->| | | | | | Update | | | | subscriber | | | | session | | | | Request | | | 11|<-----via Ci-------| | | | Update | | | | subscriber | | | | session | | | | Response | | | 12|------via Ci------>| | | | | | | | | ND negotiation | ND negotiation | 13|<------------------------->|<-----via Si------>| Hu, et al. Expires November 24, 2019 [Page 50] Internet-Draft S-CUSP for BNG May 2019 | | | | | | Update | | | | subscriber | | | | session | | | | Request | | | 14|<-----via Ci-------| | | | Update | | | | subscriber | | | | session | | | | Response | | | 15|------via Ci------>| | | | | Figure 5.4.3 L2TP-LNS IPv6 Access Step 1-12 are the same as L2TP LNS IPv4 Access. Step 1-5 finish the normal L2TP dial-up process. When the L2TP session and tunnel negotiations are finished, the LNS-CP will create a L2TP LNS subscriber session on the LNS-UP. The formats of the messages are as follows: ::= [] ::= After that, the LNS-CP will trigger a AAA authentication. If the authentication result is positive, a PPP IP6CP process will follow, then the CP will update the session with the following message exchanges: Hu, et al. Expires November 24, 2019 [Page 51] Internet-Draft S-CUSP for BNG May 2019 ::= [] ::= Then, a ND negotiation will be triggered by the RG. After the ND negotiation, the CP will update the session with the following message exchanges: ::= [] ::= 5.5. CGN (Carrier Grade NAT) Hu, et al. Expires November 24, 2019 [Page 52] Internet-Draft S-CUSP for BNG May 2019 RG UP CP AAA | | | | | | Public Address Block | | | | Allocation Request | | | 1|---------via Ci-------->| | | | Public Address Block | | | | Allocation Response | | | 2|<---------via Ci--------| | | | | | | Subscriber | | | | access request| Subscriber | | 3|-------------->| access request | | | 4|----------via Si------->| | | | | AAA | | | Subscriber | Req/Rep | | | access response 5|<------------->| | 6|<---------via Si--------| | | Subscriber | | | |access response| | | 7|<--------------| | | | | | | | | Create subscriber | | | | session Request | | | 8|<--------via Ci---------| | | | | | | | Create subscriber | | | | session Response | | | | (with NAT information) | | | 9|---------via Ci-------->| | | | | | | | | Accounting | | | | with source | | | | information | | | 10|<------------->| | | | Public IP + | | | | Port range | | | | to Private IP| | | | mapping | | | | | Figure 5.5: CGN Access The first step is to allocate one or more CGN address blocks to the UP (1-2). This is achieved by the following message exchanges between CP and UP. Hu, et al. Expires November 24, 2019 [Page 53] Internet-Draft S-CUSP for BNG May 2019 ::= ::=
Step 3-9 describe the general dial-up process in the case of CGN mode. The specific processes (e.g., IPoE, PPPoE, L2TP, etc.) are defined in above sections. If a subscriber is a CGN subscriber, once the subscriber session created/updated, the UP will report the NAT information to the CP. This is achieved by carrying the "Subscriber CGN Port Range TLV" in the Update_Response message. 5.6. L3 Leased Line Access 5.6.1. Web Authentication Hu, et al. Expires November 24, 2019 [Page 54] Internet-Draft S-CUSP for BNG May 2019 RG UP CP AAA WEB Server | | | | | | User | | | | | traffic | | | | 1|------------>| | | | | | User | | | | | traffic | | | | 2|-----via Si---->| AAA | | | | | Req/Rep | | | | 3|<-------->| | | | Create session | | | | | Request | | | | 4|<----via Ci-----| | | | | | | | | | Create session | | | | | Response | | | | 5|----via Ci----->| | | | HTTP | | | | | traffic | | | | 6|------------>| | | | | | | | | | Redirect to | | | | | Web URL | | | | 7|<------------| | | | | | | | | | | 8|-----------------Redirected to Web server----------->| | | 9|<----------------Push HTTP Log-in page---------------| | | 10|-----------------User Authentication---------------->| | | | | | Portal Interchange | | | 11|<-------------------->| | | | | | | | AAA | | | | | Req/Rep | | | | 12|<-------->| | | | | | | | | Update session | | | | | Request | | | | 13|<----via Ci-----| | | | | Update session | | | | | Response | | | | 14|----via Ci----->| | | | | | | | Figure 5.6.1: Web Authentication based L3 Leased Line Access Hu, et al. Expires November 24, 2019 [Page 55] Internet-Draft S-CUSP for BNG May 2019 In this case, IP traffic from the RG will trigger the CP to authenticate the RG by checking the source IP and the exchanges with the AAA server. Once the RG passed the authentication, the CP will create a corresponding subscriber session on the UP through the following message exchanges: IPv4 Case: ::= [] ::= [] IPv6 Case: ::= [] ::= Then, the HTTP traffic from the RG will be redirected to a WEB server to finish the WEB authentication. Once the authentication passed, the CP will trigger another AAA authentication. After the AAA authentication, the CP will update the session with the following message exchanges: Hu, et al. Expires November 24, 2019 [Page 56] Internet-Draft S-CUSP for BNG May 2019 IPv4 Case: ::= [] ::= [] IPv6 Case: ::= [] ::= 5.6.2. User Traffic Trigger RG UP CP AAA | | | | | | L3 access | | | | control list | | | 1|<----via Ci-----| | | User | | | | traffic | | | 2|------------>| | | | | User | | | | traffic | | | 3|-----via Si---->| | | | | AAA | | | | Req/Rep | | | 4|<-------->| | | | | | | Create session | | | | Request | | | 5|<----via Ci-----| | | | Create session | | | | Response | | | 6|----via Ci----->| | | | | | Figure 5.6.2: User Traffic Triggered L3 Leased Line Access Hu, et al. Expires November 24, 2019 [Page 57] Internet-Draft S-CUSP for BNG May 2019 In this user traffic triggered case, the CP must install an access control list on the UP, which is used by the UP to determine whether an RG is legal or not. If the traffic is from a legal RG, it will be redirected to the CP though the Si. The CP will trigger an AAA interchange with the AAA server. After that, the CP will create a corresponding subscriber session on the UP with the following message exchanges: IPv4 Case: ::= [] ::= [] IPv6 Case: ::= [] ::= 5.7. Multicast Access Hu, et al. Expires November 24, 2019 [Page 58] Internet-Draft S-CUSP for BNG May 2019 RG UP CP AAA | | | | | User access | User access | AAA | | request | request | Req/Rep | 1|<----------->|<----via Si---->|<-------->| | | User | | | | | | | | | | | | Create session | | | | Request | | | 2|<----via Ci---->| | | | | | | | Create session | | | | Response | | | 3|----via Ci----->| | | | | | | Multicast | | | | negotiation | | | 4|<----------->| | | | | | | Figure 5.6: Multicast Access Multicast access starts with a user access request from the RG. The request will be redirected to the CP by the Si. A follow-up AAA interchange between the CP and the AAA server will be triggered. After the authentication, the CP will create a multicast subscriber session on the UP through the following messages: Hu, et al. Expires November 24, 2019 [Page 59] Internet-Draft S-CUSP for BNG May 2019 IPv4 Case: ::= [] ::= [] IPv6 Case: ::= [] ::= 6. S-CUSP Message Formats An S-CUSP message consists of a common header followed by a variable- length body consisting entirely of TLVs. Receiving an S-CUSP message with a missing mandatory TLV must trigger an Error message (see Section 7.2 and 8.6). Conversely, if a TLV is optional, the TLV may or may not be present. Optional TLVs are indicated in the message formats shown in this document by being enclosed in square brackets. This section specifies the format of the common S-CUSP message header and lists the defined message. Network byte order is used for all multi-byte fields. 6.1. Common Message Header 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ver | Resv | Message-Type | Message-Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | Transaction-ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.1. S-CUSP Message Common Header Hu, et al. Expires November 24, 2019 [Page 60] Internet-Draft S-CUSP for BNG May 2019 o Ver (4 bits): The major version of the protocol. This document specifies version 1. Different major versions of the protocol may have significantly different message structure and format except that the Ver field will always be in the same place at the beginning of each message. A successful S-CUSP session depends on the CP and UP both using the same major version of the protocol. o Resv (4 bits): Reserved. must be sent as zero and ignored on receipt. o Message-Type (8 bits): The set of message types specified in this document is listed in Section 11.2.1. o Message-Length (16 bits): Total length of the CUSP message including the common header, expressed in number of bytes as an unsigned integer. o Transaction ID (16 bits): This field is used to identify requests. It is echoed back in any corresponding ACK / response / Error message. 6.2. Control Messages This document defines the following control messages: Type Name Notes and TLVs that can be carried ---- ---- ------------------------------------ 1 Hello Hello TLV, Keep-Alive TLV. 2 Keepalive A common header with the Keepalive message type. 3 Synch_Request Synchronization request. 4 Sync_Begin Synchronization starts. 5 Sync_Data Synchronization data: TLVs specified in Section 5. 6 Sync_End End synchronization. 7 Update_Request TLVs specified in Sections 8.7 and 8.8. 8 Update_Response TLVs specified in Sections 8.7 and 8.8. 6.2.1. Hello Message Hello message is used for S-CUSP session establishment and version negotiation. The detail of S-CUSP session establishment and version negotiation can be found in Section 4.1.1. The format of Hello message is as follows: Hu, et al. Expires November 24, 2019 [Page 61] Internet-Draft S-CUSP for BNG May 2019 ::= [] The return code and negotiation result will be carried in the Error Information TLV. They are listed as follows: 0: Success, version negotiation success. 1: Failure, malformed message received. 2: One or more of the TLVs was not understood. 1001: Version-Mismatch. The version negotiation fails. Terminate. The subsequent service processes corresponding to the UP are suspended. 6.2.2. Keepalive Message The Keepalive message is periodically sent by each end of an S-CUSP session. It is used to detect whether the peer end is still alive. The Keepalive procedures are defined Section 4.1.1. The format of Keepalive message is as follows: ::= 6.2.3. Synch_Request Message The Synch_Request message is used to request synchronization from an S-CUSP peer. Both the CP and UP can request their to peer to synchronize data. The format of Synch_Request message is as follows: ::= A Synch_Request message may result in a Synch_Begin message from its peer. The Synch_Begin message is defined in Section 6.2.4. 6.2.4. Sync_Begin Message The Sync_Begin message is a reply to a Sync_Request message. It is used to notify the synchronization requester as to whether the synchronization can be started. The format of Sync_Begin message is as follows: Hu, et al. Expires November 24, 2019 [Page 62] Internet-Draft S-CUSP for BNG May 2019 ::= The return codes are carried in the Error Information TLV. The codes are listed below: 0: Success, be ready to synchronize. 1: Failure, malformed message received. 2: One or more of the TLVs was not understood. 2001: Synch-NoReady. The data to be synchronized is not ready. 2002: Synch-Unsupport. The data synchronization is not supported. 6.2.5. Sync_Data Message The Sync_Data message is used to synchronize data between CP and UP. Sync_Data message has the same function and format as Update_Request message. The difference is that there is no ACK for Sync_Data message. An error caused by the Sync_Data message will result in a Sync_End message. There are two scenarios: Synchronization from UP to CP: Synchronize the resource data to CP. ::= [] Synchronization from CP to UP: Synchronize all subscriber sessions to UP. As for which TLVs should be carried, it depends on the specific session data to be synchronized. This is equivalent to create the specific session. Refer to Section 4.2.5 to see more details. ::= [] [] [] [] [] Hu, et al. Expires November 24, 2019 [Page 63] Internet-Draft S-CUSP for BNG May 2019 6.2.6. Sync_End Message The Sync_End message is used to indicate the end of synchronization process. The format of Sync_End message is as follows: ::= The return/error codes are listed as follows: 0: Success, synchronization finished. 1: Failure, malformed message received. 2: One or more of the TLVs was not understood. 6.2.7. Update_Request Message The Update_Request message is a multi-task message, it can be used to create, update and delete subscriber session on a UP. For session operations, the specific operation is controlled by the "Oper" field of the carried TLVs. As defined in Section 7.1, the "Oper" can be set to either "update" or "delete" when a TLV is carried in an Update_Request message. When the "Oper" set to update, it means to create or update a subscriber session, if the "Oper" set to delete, it indicates to delete a corresponding session on a UP. The format of Update_Request message is as follows: ::= [] [] [] [] [] Each Update_Request message will result in a UPdate_Response message that is defined in Section 6.2.8. 6.2.8. Update_Response Message The Update_Response message is a response to a UPdate_Request message. It is used to confirm the update request. The format of Update_Response message is as follows: Hu, et al. Expires November 24, 2019 [Page 64] Internet-Draft S-CUSP for BNG May 2019 ::= [] [] The return/error codes are carried in the Error Information TLV. They are listed as follows: 0: Success. 1: Failure, malformed message received. 2: One or more of the TLVs was not understood. 3001(Pool-Mismatch): The corresponding address pool cannot be found. 3002 (Pool-Full): The address pool is fully allocated and no address segment is available. 3003 (Subnet-Mismatch): The address pool subnet cannot be found. 3004 (Subnet-Conflict): Subnets in the address pool have been classified into other clients. 4001 (Update-Fail-No-Res): The forwarding table fails to be delivered because the forwarding resources are insufficient. 4002 (QoS-Update-Success): The QoS policy takes effect. 4003 (QoS-Update-Sq-Fail): Failed to process the queue in the QoS policy. 4004 (QoS-Update-CAR-Fail): Processing of the CAR in the QoS policy fails. 4005 (Statistic-Fail-No-Res): Statistics processing failed due to insufficient statistics resources. 6.3. Event Message The Event message is used to report subscriber session traffic statistics and detection information. The format of Event message is as follows: ::= [] [] Hu, et al. Expires November 24, 2019 [Page 65] Internet-Draft S-CUSP for BNG May 2019 6.4. Report Message The Report message is used to report board and interface status on a UP. The format of Report message is as follows: ::= [] [] 6.5. CGN Messages This document defines the following resource allocation messages: Type Name Notes and TLVs that can be carried ---- ------------------- ------------------------------------ 200 Addr_Allocation_Req Addr-Alloc-Req 201 Addr_Allocation_Ack Addr-Alloc-Resp 202 Addr_Renew_Req Addr-Renew-Req 203 Addr_Renew_Ack Addr-Renew-Resp 204 Addr_Release_Req Addr-Release-Req 205 Addr_Release_Ack Addr-Release-Resp 6.5.1. Addr_Allocation_Req Message The Addr_Allocation_Req message is used to request CGN address allocation. The format of Addr_Allocation_Req message is as follows: ::=
6.5.2. Addr_Allocation_Ack Message The Addr_Allocation_Ack message is a response to an Addr_Allocation_Req message. The format of Addr_Allocation_Ack message is as follows: ::=
6.5.3. Addr_Renew_Req Message The Addr_Renew_Req message is used to request address renewal. The format of Addr_Renew_Req message is as follows: ::=
Hu, et al. Expires November 24, 2019 [Page 66] Internet-Draft S-CUSP for BNG May 2019 6.5.4. Addr_Renew_Ack Message The Addr_Renew_Ack message is a response to an Addr_Renew_Req message. The format of Addr_Renew_Req message is as follows: ::=
6.5.5. Addr_Release_Req Message The Addr_Release_Req message is used to request address release. The format of Addr_Release_Req message is as follows: ::=
6.5.6. Addr_Release_Ack Message The Addr_Release_Ack message is a response to an Addr_Release_Req message. The format of Addr_Release_Ack message is as follows: ::=
6.6. Vendor Message The vendor message is as follows: Type Name Notes and TLVs that can be carried ---- ---- ------------------------------------ 11 Vendor Vendor-Defined, any other TLV(s) as implemented by the vendor. 7. S-CUSP TLVs and Sub-TLVs This section specifies the following o the format of the TLVs that appear in S-CUSP messages, o the format of the sub-TLVs that appear within the values of some TLVs, and o the format of some basic data fields that appear within TLVs or sub-TLVs. In addition, it lists all defined TLVs and sub-TLVs. Hu, et al. Expires November 24, 2019 [Page 67] Internet-Draft S-CUSP for BNG May 2019 7.1. Common TLV Header S-CUSP messages consist of the common header specified in Section 7.1 followed by TLVs formatted as specified in this section. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Oper | TLV-Type | TLV-Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-... Figure 7.1. Common TLV Header o Oper (4 bits): For Message-Types that indicate an operation on a data set, the Oper field is interpreted as Update, Delete, or Reserved as specified in Section 9.3. For all other Message- Types, the Oper field must be sent as zero and ignored on receipt. o TLV-Type (12 bits): The Type of a TLV, that is the meaning and format of the Value part, are determined by the TLV- Type of the TLV. See Section 9.2. o TLV-Length (2 bytes): The length of the Value portion of the TLV in bytes as an unsigned integer. o Value (variable length): This is the value portion of the TLV whose size is given by TLV-Length. The value portion consists of fields, frequently using one of the basic data field types (see Section 7.2) and sub-TLVs (see Section 7.3). 7.2. Basic Data Fields This section specifies the binary format of several standard basic data fields that are used within other data structures in this specification. o STRING: 0 to 255 octets. Will be encoded as a sub-TLV (see Section 7.3) to provide the length. o MAC-Addr: 6 octets. Ethernet MAC Address. o IPv4-Address: 8 octets. 4 octets of the IPv4 address value followed by a 4 octet address mask in the format XXX.XXX.XXX.XXX. Hu, et al. Expires November 24, 2019 [Page 68] Internet-Draft S-CUSP for BNG May 2019 o IPv6-Address: 20 octets. 16 octets of IPv6 address followed by a 4 octet integer n in the range of 0 to 128 which gives the address mask as the one's complement of 2**(128-n) - 1. o VLAN ID: 2 octets. As follows [802.1Q]: 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | PRI |D| VLAN-ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ PRI: Priority. Default value 7. D: Drop Eligibility Indicator (DEI). Default value 0. VLAN-ID: Unsigned integer in the range 1-4094. (0 and 4095 are not valid VLAN IDs[802.1Q].) 7.3. Sub-TLV Format and Sub-TLVs In some cases, the Value portion of a TLV, as specified above, can contain one or more Sub-TLVs formatted as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-... Figure 7.3. Sub-TLV Header o Type (2 bytes): The Type of a Sub-TLV, that is the meaning and format of the Value part, are determined by the Type of the sub- TLV. Sub-TLV Types numbers have the same meaning regardless of the TLV Type of the TLV within which the sub-TLV occurs. See Section 9.4. o Length (2 bytes): The length of the Value portion of the sub-TLV in bytes as an unsigned integer. o Value (variable length): This is the value portion of the sub-TLV whose size is given by Length. The sub-TLVs currently specified are defined in the following subsections. Hu, et al. Expires November 24, 2019 [Page 69] Internet-Draft S-CUSP for BNG May 2019 7.3.1. Name sub-TLVs This document defines the following name sub-TLVs, it is used to carry the name of the corresponding object. The length of each sub- TLV are variable from 1 to 255 octets. The value is STRING type. Type Sub-TLV Name Meaning ----- -------------------- ------------------- 1 VRF-Name The name of a VRF 2 Ingress-QoS-Profile The name of an ingress QoS profile 3 Egress-QoS-Profile The name of an egress QoS profile 4 User-ACL-Policy The name of an ACL policy 5 Multicast-ProfileV4 The name of an IPv4 multicast profile 6 Multicast-ProfileV6 The name of an IPv6 multicast profile 7 NAT-Instance The name of a NAT instance 8 Pool-Name The name of an address pool 7.3.2. Ingress-CAR sub-TLV Ingress-CAR sub-TLV indicates the authorized upstream Committed Access Rate (CAR) parameters. The sub-TLV type of Ingress-CAR sub- TLV is 9, the sub-TLV length is 16 octets. The format is as defined below: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | CIR | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | PIR | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | CBS | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | PBD | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.3.2 Ingress-CAR sub-TLV Where: CIR: 4 bytes in length, indicates the guaranteed rate in bits/ second. PIR: 4 bytes in length, indicates the burst rate in bits/second. CBS: 4 bytes in length, indicates the token bucket in bytes. PBS: 4 bytes in length, indicates the burst token bucket in bytes. Hu, et al. Expires November 24, 2019 [Page 70] Internet-Draft S-CUSP for BNG May 2019 These fields are unsigned integers. 7.3.3. Egress-CAR sub-TLV Ingress-CAR sub-TLV indicates the authorized downstream Committed Access Rate (CAR) parameters. The sub-TLV type of Egress-CAR sub-TLV is 10, the sub-TLV length is 16 octets. The format is as defined below: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | CIR | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | PIR | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | CBS | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | PBD | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.3.3 Egress-CAR sub-TLV Where: CIR: 4 bytes in length, indicates the guaranteed rate in bits/ second. PIR: 4 bytes in length, indicates the burst rate in bits/second. CBS: 4 bytes in length, indicates the token bucket in bytes. PBS: 4 bytes in length, indicates the burst token bucket in bytes. These fields are unsigned integers. 7.3.4. If-Desc sub-TLV If-Desc sub-TLV is defined to describe an interface. The sub-TLV type is 11, the sub-TLV length is 12 octets. The sub-TLV format is as follows: Hu, et al. Expires November 24, 2019 [Page 71] Internet-Draft S-CUSP for BNG May 2019 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | If-Type | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Chassis | Slot | Port Information | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sub-Port Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.3.4. If-Desc sub-TLV Where: If-Type: 8 bits in length, indicates the type of an interface. Following types are defined in this document: 0: Reserved, 1: Fast Ethernet (FE) 2: GE 3: 10GE 4: 100GE 5: Eth-Trunk 6: Tunnel 7: VE 8-255: Reserved. Chassis: Identify the chassis that the interface belongs to. Slot: Identify the slot that the interface belongs to. Port Information if the If-Type identifies a physical interface (e.g., If Type: 1-5), the Port Information consists of a 1-byte Physical Slot number followed by a 1-byte Physical port number. If-Type identifies a virtual port (e.g., If-Type: 6-7), the Port Information consists of a 2 byte logical number of the virtual interface. Hu, et al. Expires November 24, 2019 [Page 72] Internet-Draft S-CUSP for BNG May 2019 Sub-Port number: The number of the Sub-Port. 7.3.5. IPv6 Address List sub-TLV The IPv6 Address List sub-TLV is used to convey one or more IPv6 addresses. It is carried in the IPv6 Subscriber TLV. The sub-TLV type is 12, the sub-TLV length is variable. The format of IPv6 Addresses sub-TLV is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ IPv6 Address ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ IPv6 Address ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ ... ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ IPv6 Address ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.3.5. IPv6 Address List sub-TLV Where: IP Address (IPv6-Address): Each IP Address is an IP-Address type, carries an IPv6 address. 7.4. The Hello TLV The Hello TLV is defined to be carried in the Hello message for version and capabilities negotiation. It indicates the S-CUSP sub- version and capabilities supported. The format of Hello TLV is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | VerSupported | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Vendor ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Capabilities | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.4: Hello TLV Hu, et al. Expires November 24, 2019 [Page 73] Internet-Draft S-CUSP for BNG May 2019 Where: The TLV type is 100. The TLV length is 12 octets. The value field include three parts: VerSupported: 32 bits in length. This is a bit map of the Sub- Versions of the S-CUSP protocol that the sender supports. This document specifies Sub-Version zero of Major Version 1, that is, Version 1.0. The VerSupported field must be non-zero. Bit 0 indicates support of Sub-Version zero, bit 1 indicates support of Sub-Version one, etc. Vendor-ID: 4 bytes in length. Vendor ID, as defined in RADIUS [RFC2865]. Capabilities: 32 bits in length. Flags that indicate the support of particular capabilities by the sender of the Hello. After the exchange of Hello messages, the CP and UP each perform a logical AND of the Sub-Version supported by the CP and the UP and separately perform a logical AND of the Capabilities bits fields for the CP and the UP. If the result of the AND of the Sub-Versions supported is zero, then no session can be established and the connection is torn down. If the result of the AND of the Sub-Versions supported is non-zero, then the session uses the highest Sub-Version supported by both the CP and UP. For example, if one side supports Sub-Versions 1, 3, 4, and 5 (VerSupported = 0x5C000000) and the other side supports 2, 3, and 4 (VerSupported = 0x38000000) then 3 and 4 are the Sub-Versions in common and 4 is the highest Sub-Version supported by both sides. So Sub-Version 4 is used for the session that has been negotiated. The result of the logical AND of the Capabilities bits will show what additional capabilities both sides support. If this result is zero, there are no such capabilities so none can be used during the session. If this result is non-zero, it shows the additional capabilities that can be used during the session. The CP and the UP must not use a capability unless both advertise support. Hu, et al. Expires November 24, 2019 [Page 74] Internet-Draft S-CUSP for BNG May 2019 7.5. The Keep Alive TLV The Keep Alive TLV is defined to be carried in the Hello message. It provides timing information for the keep alive feature. The format of Hello TLV is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Keepalive | DeadTimer | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.5: Keep Alive TLV Where: The TLV type: 102. The value of length: 4 octets. Keepalive, 8 bits in length. Indicates the maximum period of time (in seconds) between two consecutive S-CUSP messages sent by the sender of the message containing this TLV as an unsigned integer. The minimum value for the Keepalive is 1 second. When set to 0, once the session is established, no further Keepalive messages are sent to the remote peer. A recommended value for the Keepalive frequency is 30 seconds. DeadTimer, 8 bits in length. Specifies the amount of time as an unsigned integer number of seconds after the expiration of which the S-CUSP peer can declare the session with the sender of the Hello message to be down if no S-CUSP message has been received. The DeadTimer shouldbe set to 0 and must be ignored if the Keepalive is set to 0. A recommended value for the DeadTimer is 4 times the value of the Keepalive. 7.6. The Error Information TLV The Error Information TLV is a common TLV that can be used in many Response (e.g., Update_Response message) and ACK messages (e.g., Addr_Allocation_Ack message, etc.). It is used to convey the information about an error in the received S-CUSP message. The format of the Error Information TLV is as follows: Hu, et al. Expires November 24, 2019 [Page 75] Internet-Draft S-CUSP for BNG May 2019 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message Type | Reserved | TLV Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Status Code | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.6: Error Information TLV Where: The TLV type: 101. The value of length: 8 octets. Message-Type(1 byte): This parameter is the message type of the message containing an error. Reserved (1 byte): Must be sent as zero and ignored on receipt. TLV-Type (2 bytes): If the error was inside a TLV, this the TLV- Type of that TLV. Status Code: 4 bytes in length. Indicate the specific Error Code (see Section 11.2.5). 7.7. BAS Function Enabler TLV The BAS Function Enabler TLV is used by a CP to control the access mode, authentication methods, and other related functions of an interface on a UP. The format of the BAS Function Enabler TLV value part is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | If-Index | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Access-Mode | Auth-Method4 | Auth-Method6 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ sub-TLVs (optional) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.7: BAS Function Enabler TLV Hu, et al. Expires November 24, 2019 [Page 76] Internet-Draft S-CUSP for BNG May 2019 Where: The TLV type: 1. The value of length: variable. If-Index: 4 bytes in length, a unique identifier of an interface of a BNG. Access-Mode: 1 byte in length, indicates the access mode of the interface. This document defines following values: 0: Layer 2 subscriber; 1: Layer 3 subscriber; 2: Layer 2 leased line; 3: Layer 3 leased line; 4-255: Reserved. Auth-Method4: 1 byte in length, for IPv4 scenario, it indicates the authentication on this interface; this field is defined as a bitmap, this document defines following values (other bits are reserved and must be sent as zero and ignored on receipt): 0x1: PPPoE authentication; 0x2: DOT1X authentication; 0x4: Web authentication; 0x8: Web fast authentication; 0x10: Binding authentication. Auth-Method6: 1 byte in length, for IPv6 scenario, it indicates the authentication on this interface; this field is defined as a bitmap, this document defines following values (other bits are reserved and must be sent as zero and ignored on receipt): 0x1: PPPoE authentication; 0x2: DOT1X authentication; 0x4: Web authentication; Hu, et al. Expires November 24, 2019 [Page 77] Internet-Draft S-CUSP for BNG May 2019 0x8: Web fast authentication; 0x10: Binding authentication; The flags field is defined as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MBZ |Y|X|P|I|N|A|S|F| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.7.1: Interface Flags Where: F (IPv4 Trigger) bit: Indicates whether IPv4 packets can trigger a subscriber go to online. 1: enabled, 0: disabled. S (IPv6 Trigger) bit: Indicates whether IPv6 packets can trigger a subscriber go to online. 1: enabled, 0: disabled. A (ARP Trigger) bit: Indicates whether ARP packets can trigger a subscriber go to online. 1: enabled, 0: disabled. N (ND Trigger) bit: Indicates whether ND packets can trigger a subscriber go to online. 1: enabled, 0: disabled. I (IPoE-Flow-Check): Used for UP detection. IPoE 1: Enable traffic detection. 0: Disable traffic detection. P (PPP-Flow-Check) bit: Used for UP detection. PPP 1: Enable traffic detection. 0: Disable traffic detection. X (ARP-Proxy) bit: 1: The interface is enabled with ARP proxy and can process ARP requests across different Port+VLANs. 0: The ARP proxy is not enabled on the interface, and only the ARP requests of the same Port+VLAN are processed. Y (ND-Proxy) bit: 1: The interface is enabled with ND proxy and can process ND requests across different Port+VLANs. 0: The ND proxy is not enabled on the interface, and only the ND requests of the same Port+VLAN are processed. MBZ: Reserved bits that must be sent as zero and ignored on receipt. Hu, et al. Expires November 24, 2019 [Page 78] Internet-Draft S-CUSP for BNG May 2019 7.8. Routing TLVs Normally, after an S-CUSP session established between a UP and CP, the CP will allocate one or more blocks of IP addresses to the UP. Those IP addresses will be allocated to subscribers who will dial-up to the UP. In order to make sure that other nodes within the network learn how to reach those IP addresses, the CP needs to install one or more routes that can reach those IP addresses on the UP and notify the UP to advertise the routes to the network. The Routing TLVs are used by a CP to notify a UP of the network routing. They can be carried in the Update_Request message and Data_Sycn message. 7.8.1. IPv4 Routing TLV The IPv4 Routing TLV is used to carry IPv4 network routing related information. The format of this TLV is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Dest-Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next-Hop | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Out-If-Index | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cost | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Route Type | Reserved |A| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ sub-TLVs ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.8.1: IPv4 Routing TLV Where: The TLV Type: 7 The TLV Length: Variable Hu, et al. Expires November 24, 2019 [Page 79] Internet-Draft S-CUSP for BNG May 2019 User-ID: 4 bytes in length. Carry the user identifier. This field is filled with all Fs when a non-user route is delivered to the UP. Dest-Address: IPv4 type. Identify the destination address. Next-Hop: IPv4 type. Identify the next hop address. Out-If-Index: 4 bytes in length. Indicates the interface index. Cost: 4 bytes in length. The cost value of the route. Tag: 4 bytes in length. The tag value of the route. Route-Type: 2 bytes in length. Indicate the route type. The options are as follows: 0: User host route 1: Radius authorization FrameRoute 2: Network segment route 3: Gateway route 4: Radius authorized IP route 5: L2TP LNS side user route Advertise-Flag:1 bit. Indicates whether the route should be advertised by the UP. Following flags are defined: 0: Not advertised, 1: advertised. sub-TLVs: VRF-Name Sub-TLV can be carried. The Reserved field must be sent as zero and ignored on receipt. 7.8.2. IPv6 Routing TLV The IPv6 Routing TLV is used to carry IPv6 network routing information. The format of the this TLV is as follows: Hu, et al. Expires November 24, 2019 [Page 80] Internet-Draft S-CUSP for BNG May 2019 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ IPv6 Dest-Address ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ IPv6 Next-Hop ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Out-If-Index | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cost | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Route Type | Reserved |A| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ VRF-Name sub-TLVs ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.8.2: IPv6 Routing TLV Where: The TLV Type: 7 The TLV Length: Variable User-ID: 4 bytes in length. Carry the user identifier. This field is filled with all Fs when a non-user route is delivered to the UP. IPv6 Dest-Address: IPv6 type. Identify the destination address. IPv6 Next-Hop: IPv6 type. Identify the next hop address. Out-If-Index: 4 bytes in length. Indicates the interface index. Cost: 4 bytes in length. The cost value of the route. Tag: 4 bytes in length. The tag value of the route. Route-Type: 2 bytes in length. Indicate the route type. The options are as follows: 0: User host route 1: Radius authorization FrameRoute Hu, et al. Expires November 24, 2019 [Page 81] Internet-Draft S-CUSP for BNG May 2019 2: Network segment route 3: Gateway route 4: Radius authorized IP route 5: L2TP LNS side user route Advertise-Flag:1 bit. Indicates whether the route should be advertised by the UP. Following flags are defined: 0: Not advertised, 1: advertised. VRF-Name Sub-TLV: Indicates the subscriber belongs to which VRF. The Reserved field must be sent as zero and ignored on receipt. 7.9. Subscriber TLVs 7.9.1. Basic Subscriber TLV The Basic Subscriber TLV is used to carry the basic common information for all kinds of access subscribers. It is carried in a UPdate_Request message. The format of the Basic Subscriber TLV value part is as follows: Hu, et al. Expires November 24, 2019 [Page 82] Internet-Draft S-CUSP for BNG May 2019 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User MAC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User MAC (cont.) | Oper ID | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Access Type |Sub-access Type| Account Type | Address Family| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | C-VID | P-VID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Detect Times | Detect Interval | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | If-Index | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ sub-TLVs (optional) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.9.1: Basic Subscriber TLV Where: The TLV Type: 2 The TLV Length: variable in length; User-ID (4 bytes): The identifier of a subscriber. User-Mac (MAC-Addr): The MAC Address of a subscriber. Oper-ID (1 byte): Indicates the ID of an operation performed by a user. This field is carried in the response from the UP. Session-ID (4 bytes): Session ID of a PPPoE subscriber. Zero means non-PPPoE subscriber. Access-Type (1 byte): 1: PPP access (PPP) 2: PPP over Ethernet over ATM access (PPPoEoA) 3: PPP over ATM access (PPPoA) Hu, et al. Expires November 24, 2019 [Page 83] Internet-Draft S-CUSP for BNG May 2019 4: PPP over Ethernet access (PPPoE) 5: PPPoE over VLAN access (PPPoEoVLAN) 6: PPP over LNS access (PPPoLNS) 7: IP over Ethernet DHCP access (IPoE_DHCP) 8: IP over Ethernet EAP authentication access (IPoE_EAP) 9: IP over Ethernet Layer 3 access (IPoE_L3) 10: IP over Ethernet Layer 2 Static access (IPoE_L2_STATIC) 11: Layer 2 Leased Line access (L2_Leased_Line) 12: Layer 2 VPN Leased Line access (L2VPN_Leased_Line) 13: Layer 3 Leased Line access (L3_Leased_Line) 14: Layer 2 Leased line Sub-User access (L2_Leased_Line_SUB_USER) 15: L2TP LAC tunnel access (L2TP_LAC) 16: L2TP LNS tunnel access (L2TP_LNS) Sub-Access-Type (1 byte): Indicates whether PPP termination or PPP relay is used. 0: Reserved 1: PPP Relay (for LAC) 2: PPP termination (for LNS) Account-Type(1 byte): 0: Collects statistics on IPv4 and IPv6 traffic of terminals independently. 1: Collects statistics on IPv4 and IPv6 traffic of terminals. Address Family (1 byte) 1: IPv4 2: IPv6 Hu, et al. Expires November 24, 2019 [Page 84] Internet-Draft S-CUSP for BNG May 2019 3: dual stack C-VID (VLAN-ID): Indicates the inner VLAN ID. The value 0 indicates that the VLAN ID is invalid. The default value of PRI is 7, the value of DEI is 0, and the value of VID is 1~4094. The PRI value can also be obtained by parsing terminal packets. P-VID (VLAN-ID): Indicates the outer VLAN ID. The value 0 indicates that the VLAN ID is invalid. The format is the same as that the C-VID. Detect-Times (2 bytes): Number of detection timeout times. The value 0 indicates that no detection is performed. Detect-Interval (2 bytes): Detection interval in seconds. If-Index (4 bytes): Interface index. The Reserved field must be sent as zero and ignored on receipt. 7.9.2. PPP Subscriber TLV The PPP Subscriber TLV is defined to carry PPP information of a User, from a CP to a UP. It will be carried in a UPdate_Request message when PPPoE or L2TP access is used. The format of the TLV value part is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MSS | Reserved |M| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MRU | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Magic Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Peer Magic Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.9.2: PPP Subscriber TLV Where: The TLV type: 3. Hu, et al. Expires November 24, 2019 [Page 85] Internet-Draft S-CUSP for BNG May 2019 The TLV length: 12 octets. User-ID (4 bytes): The identifier of a subscriber. MSS-Value(2 bytes): Indicates the MSS value. MSS-Enable(1 bit): Indicates whether the MSS is enabled. 0: Disabled. 1: Enabled. MRU(2 bytes): PPPoE local MRU. Magic-Number(4 bytes): Local magic number in PPP negotiation packets. Peer-Magic-Number (4 bytes): Remote peer magic number. The Reserved fields must be sent as zero and ignored on receipt. 7.9.3. IPv4 Subscriber TLV The IPv4 Subscriber TLV is defined to carry IPv4 related information for a BNG user. It will be carried in a UPdate_Request message when IPv4 IPoE, PPPoE access are used. The format of the TLV value part is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User IPv4 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Gateway IPv4 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MTU | Reserved |U|E|W|P| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ VRF-Name sub-TLV ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.9.3: IPv4 Subscriber TLV Where: The TLV type: 4. Hu, et al. Expires November 24, 2019 [Page 86] Internet-Draft S-CUSP for BNG May 2019 The TLV length: variable. User-ID (4 bytes): The identifier of a subscriber. User-IPv4 (IPv4-Address): The IPv4 address of the subscriber. Gateway-IPv4 (IPv4-Address): The gateway address of the subscriber. Portal Force (P) (1 bit ): Push advertisement, 0: off, 1: on. Web-Force (W) (1 bit): Push IPv4 Web. 0: off, 1: on. Echo-Enable (E) (1 bit): UP returns ARP Req or PPP Echo. 0: off, 1: on. IPv4-URPF (U) (1 bit): User Unicast Reverse Path Forwarding (URPF) flag. 0: off, 1: on. MTU 2 bytes MTU value. The default value is 1500. VRF-Name Sub-TLV: Indicates the subscriber belongs to which VRF. The Reserved field must be sent as zero and ignored on receipt. 7.9.4. IPv6 Subscriber TLV The IPv6 Subscriber TLV is defined to carry IPv6 related information for a BNG user. It will be carried in a UPdate_Request message when IPv6 IPoE, PPPoE access are used. The format of the TLV value part is as follows: Hu, et al. Expires November 24, 2019 [Page 87] Internet-Draft S-CUSP for BNG May 2019 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ User PD-Addresses (IPv6 Address List sub-TLV) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Gateway ND-Addresses (IPv6 Address List sub-TLV) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User IANA Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 Interface ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 Interface ID (cont.) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MTU | Reserved |U|E|W|P| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ VRF Name sub-TLV ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.9.4: IPv6 Subscriber TLV Where: The TLV type: 5. The TLV length: variable. User-ID (4 bytes): The identifier of a subscriber. User PD-Addresses (IPv6 Address List): Carry a list of Prefix Delegation (PD) addresses of the subscriber. User ND-Addresses (IPv6 Address List): Carry a list of Neighbor Discovery (ND) addresses of the subscriber. User IANA-Address (IPv6-Address): The IANA address of the subscriber. . IPv6 Interface ID (8 bytes): The identifier of an IPv6 interface. Portal Force 1 bit (P): Push advertisement, 0: off, 1: on. Web-Force 1 bit (W): Push IPv6 Web, 0: off, 1: on. Echo-Enable 1 bit (E): The UP returns ARP Req or PPP Echo. 0: off; 1: on. Hu, et al. Expires November 24, 2019 [Page 88] Internet-Draft S-CUSP for BNG May 2019 IPv6-URPF 1 bit (U): User Reverse Path Forwarding (URPF) flag, 0: off; 1: on. MTU (2 bytes): The MTU value. The default value is 1500. VRF-Name Sub-TLV: Indicates the subscriber belongs to which VRF. The Reserved field must be sent as zero and ignored on receipt. 7.9.5. IPv4 Static Subscriber TLV The IPv4 Static Subscriber TLV is defined to carry IPv4 related information for a static access BNG user. It will be carried in a UPdate_Request message when IPv4 static access is used. The format of the TLV value part is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | If-Index | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | C-VID | P-VID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Gateway Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User MAC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User MAC (cont.) | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ VRF-Name sub-TLV ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.9.5: IPv4 Static Subscriber TLV Where: The TLV type: 6. The TLV length: variable. If-Index (4 bytes): The interface index of the interface from which the subscriber will dial-up. C-VID (VLAN-ID): Indicates the inner VLAN ID. The value 0 indicates that the VLAN ID is invalid. Valid values are 1~4094. Hu, et al. Expires November 24, 2019 [Page 89] Internet-Draft S-CUSP for BNG May 2019 P-VID (VLAN-ID): Indicates the outer VLAN ID. The value 0 indicates that the VLAN ID is invalid. The format is the same as that of the C-VID. Valid values are 1~4094. For a single-layer VLAN, set this parameter to PeVid. User Address (IPv4-Addr): The user's IPv4 address. Gateway Address (IPv4-Addr): The gateway's IPv4 Address. User-MAC (MAC-Addr): The MAC address of the subscriber. VRF-Name Sub-TLV: Indicates the subscriber belongs to which VRF. The Reserved field must be sent as zero and ignored on receipt. 7.9.6. IPv6 Static Subscriber TLV The IPv6 Static Subscriber TLV is defined to carry IPv6 related information for a static access BNG subscriber. It will be carried in a UPdate_Request message when IPv6 static access is used. The format of the TLV value part is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | If-Index | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | C-VID | P-VID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ User Address ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Gateway Address ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User MAC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User MAC (cont.) | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ VRF-Name sub-TLV ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.9.6: Static IPv6 Subscriber TLV Where: The TLV type: 6. The TLV length: variable. Hu, et al. Expires November 24, 2019 [Page 90] Internet-Draft S-CUSP for BNG May 2019 If-Index (4 bytes): The interface index of the interface from which the subscriber will dial-up. C-VID (VLAN-ID): Indicates the inner VLAN ID. The value 0 indicates that the VLAN ID is invalid. Valid values are 1~4094. P-VID (VLAN-ID): Indicates the outer VLAN ID. The value 0 indicates that the VLAN ID is invalid. The format is the same as that of the C-VID. Valid values are 1~4094. For a single-layer VLAN, set this parameter to PeVid. User Address (IPv6-Addr): The subscriber's IPv6 address. Gateway Address (IPv6-Addr): The gateway's IPv6 Address. User-MAC (MAC-Addr): The MAC address of the subscriber. VRF-Name Sub-TLV: Indicates the subscriber belongs to which VRF. The Reserved field must be sent as zero and ignored on receipt. 7.9.7. L2TP-LAC Subscriber TLV The L2TP-LAC Subscriber TLV is defined to carry the related information for a L2TP LAC access subscriber. It will be carried in a UPdate_Request message when L2TP LAC access is used. The format of the TLV value part is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Local Tunnel ID | Local Session ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Remote Tunnel ID | Remote Session ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.9.7: L2TP-LAC Subscriber TLV Where: The TLV type: 11. The TLV length: 12 octets. User-ID (4 bytes): The identifier of a user/subscriber. Hu, et al. Expires November 24, 2019 [Page 91] Internet-Draft S-CUSP for BNG May 2019 Local-Tunnel-ID (2 bytes): The local ID of the L2TP tunnel. Local-Session-ID (2 bytes): The local session ID with the L2TP tunnel. Remote-Tunnel-ID (2 bytes): The remote ID of the L2TP tunnel. Remote-Session-ID (2 bytes): The remote session ID of the L2TP tunnel. 7.9.8. L2TP-LNS Subscriber TLV The L2TP-LAC Subscriber TLV is defined to carry the related information for a L2TP LNS access subscriber. It will be carried in a UPdate_Request message when L2TP LNS access is used. The format of the TLV value part is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Local Tunnel ID | Local Session ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Remote Tunnel ID | Remote Session ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.9.8: L2TP-LAC Subscriber Information TLV Where: The TLV type: 12. The TLV length: 12 octets. User-ID (4 bytes): The identifier of a user/subscriber. Local-Tunnel-ID (2 bytes): The local ID of the L2TP tunnel. Local-Session-ID (2 bytes): The local session ID with the L2TP tunnel. Remote-Tunnel-ID (2 bytes): The remote ID of the L2TP tunnel. Remote-Session-ID (2 bytes): The remote session ID of the L2TP tunnel. Hu, et al. Expires November 24, 2019 [Page 92] Internet-Draft S-CUSP for BNG May 2019 7.9.9. L2TP-LAC Tunnel TLV The L2TP-LAC Tunnel TLV is defined to carry the L2TP LAC tunnel related information. It will be carried in the Update_Request message when L2TP LAC access is used. The format of the TLV value part is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Local Tunnel ID | Remote Tunnel ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Port | Destination Port | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Tunnel Source Address ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Tunnel Destination Address ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ sub-TLV (VRF Name sub-TLV) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.9.9: L2TP-LAC Tunnel TLV where: The TLV type: 13. The TLV length: variable. Local-Tunnel-ID (2 bytes): The local ID of the L2TP tunnel. Remote-Tunnel-ID (2 bytes): The remote ID of the L2TP tunnel. Source-Port (2 bytes): The source UDP port number of an L2TP subscriber. Dest-Port (2 bytes): The destination UDP port number of an L2TP subscriber. Source-IP (IPv4/v6): The source IP address of the tunnel. Dest-IP (IPv4/v6): The destination IP address of the tunnel. VRF-Name Sub-TLV: The VRF name to which the L2TP subscriber tunnel belongs. Hu, et al. Expires November 24, 2019 [Page 93] Internet-Draft S-CUSP for BNG May 2019 7.9.10. L2TP-LNS Tunnel TLV The L2TP-LNS Tunnel TLV is defined to carry the L2TP LNS tunnel related information. It will be carried in the Update_Request message when L2TP LNS access is used. The format of the TLV value part is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Local Tunnel ID | Remote Tunnel ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Port | Destination Port | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Tunnel Source Address ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Tunnel Destination Address ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ sub-TLV (VRF Name sub-TLV) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.9.10: L2TP-LAC Tunnel TLV where: The TLV type: 14. The TLV length: variable. Local-Tunnel-ID (2 bytes): The local ID of the L2TP tunnel. Remote-Tunnel-ID (2 bytes): The remote ID of the L2TP tunnel. Source-Port (2 bytes): The source UDP port number of an L2TP subscriber. Dest-Port (2 bytes): The destination UDP port number of an L2TP subscriber. Source-IP (IPv4/v6): The source IP address of the tunnel. Dest-IP (IPv4/v6): The destination IP address of the tunnel. VRF-Name Sub-TLV: The VRF name to which the L2TP subscriber tunnel belongs. Hu, et al. Expires November 24, 2019 [Page 94] Internet-Draft S-CUSP for BNG May 2019 7.9.11. Session Update Response TLV The Session Update Response TLV is used to return the operation result when updating a subscriber session. It is carried in the Update_Response message as a response to the Update_Request message. The format of Session Update Response TLV is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User-ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User-Trans-ID | Oper Code | Oper Result | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Error Code | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.9.11: Session Update Response TLV Where: The TLV type: 302. The TLV length: 12. User-ID (4 bytes): A unique identifier of a user/subscriber. User-Trans-ID (1 byte): In the case of dual-stack access or when modify a session, User-Trans-ID is used to identify a user operation transaction. It is used by the CP to correlate a response to a specific request. Oper-Code (1 byte): Operation code. 1: update, 2: delete. Oper-Result (1 byte): Operation Result. 0: Success, Others: Failure Error-Code (4 bytes): Operation failure cause code. For details, see Section 9.5. The Reserved field must be sent as zero and ignored on receipt. 7.9.12. Subscriber Policy TLV The Subscriber Policy TLV is used to carry the policies that will be applied to a subscriber. It is carried in the Update_Request message. Hu, et al. Expires November 24, 2019 [Page 95] Internet-Draft S-CUSP for BNG May 2019 The format of the TLV value part is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | I-Priority | E-Priority | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ sub-TLVs ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.9.12: Subscriber Policy TLV Where: The TLV type: 6. The TLV length: variable. User-ID (4 bytes): The identifier of a user/subscriber. Ingress-Priority (1 byte): Indicates the upstream priority. The value range is 0~7. Egress-Priority (1 byte): Indicates the downstream priority. The value range is 0~7. sub-TLVs: Ingress-CAR sub-TLV): Upstream CAR. Egress-CAR sub-TLV: Downstream CAR. Ingress-QoS-Profile sub-TLV: Indicates the name of the QoS- Profile profile in the upstream direction. Egress-QoS-Profile Sub-TLV: Indicates the name of the QoS- Profile profile in the downstream direction. User-ACL-Policy Sub-TLV: All ACL user policies, including v4ACLIN, v4ACLOUT, v6ACLIN, v6ACLOUT, v4WEBACL, v6WEBACL, v4SpecialACL, and v6SpecialACL. Multicast-Profile4 Sub-TLV: IPv4 multicast policy name. Multicast-Profile6 Sub-TLV: IPv6 multicast policy name. Hu, et al. Expires November 24, 2019 [Page 96] Internet-Draft S-CUSP for BNG May 2019 NAT-Instance Sub-TLV: Indicates the instance ID of a NAT user. The Reserved field must be sent as zero and ignored on receipt. 7.9.13. Subscriber CGN Port Range TLV The Subscriber CGN Port Range TLV is used to carry the NAT public address and port range. It will be carried in the Update_Response message when CGN is used. The format of this TLV is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NAT Port Start | NAT Port End | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NAT Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.9.13: Subscriber CGN Port Range TLV Where: The TLV type: 15. The TLV length: 12 octets. User-ID (4 bytes): The identifier of a user/subscriber. NAT-Port-Start (2 bytes): The start port number. NAT-Port-End (2 bytes): The end port number. NAT-Sub-IP (4 bytes): The NAT public network address. 7.10. Device Status TLVs 7.10.1. Interface Status TLV The Board Status TLV is used to carry the status information of an interface on a UP. It is carried in a Report message. The format of this TLV is as follows: Hu, et al. Expires November 24, 2019 [Page 97] Internet-Draft S-CUSP for BNG May 2019 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | If-Index | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC Address (upper part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC Address (lower part) | Phy-State | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MTU | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ sub-TLVs (optional) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.10.1: Interface Status TLV Where: The TLV type: 200. The TLV length: variable. If-Index (4 bytes): Indicates the interface index. MAC-Address (MAC-Addr): Interface MAC address. Phy-State (1 byte): Physical status of the interface. 0: down, 1: Up MTU (4 bytes): Interface MTU value. The Reserved field must be sent as zero and ignored on receipt. 7.10.2. Board Status TLV The Board Status TLV is used to carry the status information of a board on a UP. It is carried in a Report message. The format of Board Status TLV is as follows: Hu, et al. Expires November 24, 2019 [Page 98] Internet-Draft S-CUSP for BNG May 2019 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Chassis | Slot | Sub-Slot | Board-Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Board-State | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.10.2: Board Status TLV Where: The TLV type: 201. The TLV length: 8 octets. Chassis (1 byte): The chassis number of the board. Slot (1 byte): The slot number of the board. Sub-Slot (1 byte): The sub-slot number of the board. Board Type (1 byte): 1: CGN Service Process Unit (SPU) board. 2: Line Process Unit (LPU) board. Board-State (1 byte): 0: Normal. 1: Abnormal. The reserved field must be sent as zero and ignored on receipt. 7.11. CGN TLVs 7.11.1. Address Allocation Request TLV The Address Allocation Request TLV is used to request address allocation from CP. An address Pool-Name sub-TLV is carried to indicate from which address pool to allocate addresses. The Address Allocation Request TLV is carried in the Addr_Allocation_Req message. The format of this TLV is as follows: Hu, et al. Expires November 24, 2019 [Page 99] Internet-Draft S-CUSP for BNG May 2019 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ sub-TLV ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.11.1: Address Allocation Request TLV Where: The TLV type: 400. The TLV length: variable. sub-TLV: Carry a Pool-Name Sub-TLV to indicate from which Address pool to allocate address. 7.11.2. Address Allocation Response TLV The Address Allocation Response TLV is used to return the address allocation result, it is carried the Addr_Allocation_Ack message. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Lease Time | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Addr and Mask | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Addr and Mask continued | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Return Code | Reserved | ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ sub-TLVs | ~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.11.2: Address Assignment Response TLV Where: The TLV type: 401. The TLV length: variable. Lease Time (4 bytes): Duration of address lease in seconds. IPv4 Addr and Mask (IPv4-Addr): The allocated IPv4 address. Hu, et al. Expires November 24, 2019 [Page 100] Internet-Draft S-CUSP for BNG May 2019 Return Code (1 byte): 0: Success. 1: Failure. 3001 (Pool-Mismatch): The corresponding address pool cannot be found. 3002 (Pool-Full): The address pool is fully allocated and no address segment is available. sub-TLVs: Carry a Pool-Name Sub-TLV to indicate from which Address pool the address is allocated. 7.11.3. Address Renewal Request TLV The Address Renewal Request TLV is used to request address renewal from the CP. It is carried the Addr_Renew_Req message. The format of this TLV is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Address and Mask | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Address and Mask continued | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ sub-TLVs ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.11.3: Address Renewal Request TLV Where: The TLV type: 402. The TLV length: variable. IPv4 Addr and Mask (IPv4-Addr): The IPv4 address to be renewed. sub-TLVs: Carry a Pool-Name Sub-TLV to indicate from which Address pool to renew the address. Hu, et al. Expires November 24, 2019 [Page 101] Internet-Draft S-CUSP for BNG May 2019 7.11.4. Address Renewal Response TLV The Address Renewal Response TLV is used to return the address renewal result. It is carried in the Addr_Renew_Ack message. The format of this TLV is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Address and Mask | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Address and Mask continued | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Return-Code | Reserved | ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ sub-TLVs | ~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.11.4: Address Renewal Response TLV Where: The TLV type: 403. The TLV length: variable. Client-IP (IPv4-Addr): The renewed IPv4 address. Return-Code (1 bytes): 0: Renew success. 1: Renew failed. 3001 (Pool-Mismatch): The corresponding address pool cannot be found. 3002 (Pool-Full): The address pool is fully allocated and no address segment is available. 3003 (Subnet-Mismatch): The address pool subnet cannot be found. 3004 (Subnet-Conflict): Subnets in the address pool have been assigned to other clients. Hu, et al. Expires November 24, 2019 [Page 102] Internet-Draft S-CUSP for BNG May 2019 sub-TLVs: Carry a Pool-Name Sub-TLV to indicate from which Address pool to renew the address. 7.11.5. Address Release Request TLV The Address Release Request TLV is used to release an IPv4 address. It is carried in the Addr_Release_Req message. The format of this TLV is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Address and Mask | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Address and Mask continued | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ sub-TLVs ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.11.5: Address Release Request TLV Where: The TLV type: 404. The TLV length: variable. IPv4 Address and Mask (IPv4-Addr): The IPv4 address be released. sub-TLVs: carry a Pool-Name Sub-TLV to indicate from which Address pool to release the address. 7.11.6. Address Release Response TLV The Address Release Response TLV is used to return the address release result. It is carried in the Addr_Release_Ack message. The format of this TLV is as follows: Hu, et al. Expires November 24, 2019 [Page 103] Internet-Draft S-CUSP for BNG May 2019 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Address and Mask | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Address and Mask continued | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Result-Code | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ sub-TLVs ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.11.6: Address Release Response TLV Where: The TLV type: 405. The TLV length: variable. Client-IP (IPv4-Addr): The released IPv4 address. Return-Code (1 bytes): 0: Address release success. 1: Address release failed. 3001 (Pool-Mismatch): The corresponding address pool cannot be found. 3003 (Subnet-Mismatch): The address cannot be found. 3004 (Subnet-Conflict): The address has been allocated to another subscriber. sub-TLVs: carry a Pool-Name Sub-TLV to indicate from which address pool to release the address. 7.12. Event TLVs 7.12.1. Subscriber Traffic Statistics TLV The Subscriber Traffic Statistics TLV is used to return the traffic statistics of a user/subscriber. The format of this TLV is as follows: Hu, et al. Expires November 24, 2019 [Page 104] Internet-Draft S-CUSP for BNG May 2019 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User-ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Statistics-Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ingress Packets (upper part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ingress Packets (lower part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ingress Bytes (upper part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ingress Bytes (lower part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ingress Loss Packets (upper part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ingress Loss Packets (lower part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ingress Loss Bytes (upper part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ingress Loss Bytes (lower part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Egress Packets (upper part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Egress Packets (lower part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Egress Bytes (upper part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Egress Bytes (lower part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Egress Loss Packets (upper part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Egress Loss Packets (lower part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Egress Loss Bytes (upper part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Egress Loss Bytes (lower part) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.12.1: Subscriber Traffic Statistics TLV Where: The TLV type: 300. The TLV length: 72 octets. User-ID (4 bytes): The user/subscriber identifier. Hu, et al. Expires November 24, 2019 [Page 105] Internet-Draft S-CUSP for BNG May 2019 Statistics-Type (4 bytes): Traffic type. It can be one of the following options: 0: IPv4 traffic. 1: IPv6 traffic. 2: Dual stack traffic. Ingress Packets (8 bytes): The number of the packets in upstream direction. Ingress Bytes (8 bytes): The bytes of the upstream traffic. Ingress Loss Packets (8 bytes): The number of the lost packets in upstream direction. Ingress Loss Bytes (8 bytes): The bytes of the lost upstream packets. Egress Packets (8 bytes): The number of the packets in downstream direction. Egress Bytes (8 bytes): The bytes of the downstream traffic. Egress Loss Packets (8 bytes): The number of the lost packets in downstream direction. Egress Loss Bytes (8 bytes): The bytes of the lost downstream packets. 7.12.2. Subscriber Detection Result TLV The Subscriber Detection Result TLV is used to return the detection result of a subscriber. Subscriber detection is a function to detect whether a subscriber is online or not. The result can be used by the CP to determine how to deal with the subscriber session. (e.g., delete the session if detection failed). 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User-ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Detect Type | Detect Result | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.12.2: Subscriber Detection Result TLV Hu, et al. Expires November 24, 2019 [Page 106] Internet-Draft S-CUSP for BNG May 2019 Where: The TLV type: 301. The TLV length: 8 octets. User-ID (4 bytes): a user/subscriber identifier. Detect-Type (1 byte): 0: IPv4 detection. 1: IPv6 detection. 2: PPP detection. Detect-Result (1 bytes): 0: Indicates that the detection is successful. 1: Detection failure. The UP needs report only when the detection fails. The Reserved field must be sent as zero and ignored on receipt. 7.13. Vendor TLV 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Vendor ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sub-Type | Sub-Type-Version | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ sub-TLVs (optional) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7.13: Vendor TLV Where: The TLV type: 1024. The TLV length: variable. Vendor-ID (4 bytes): Vendor ID, which is defined in the RADIUS [RFC2865]. Hu, et al. Expires November 24, 2019 [Page 107] Internet-Draft S-CUSP for BNG May 2019 Sub-Type (2 bytes): Used by the Vendor to distinguish multiple different vendor messages. Sub-Type-Version (2 bytes): Used by the Vendor to distinguish different versions of a Vendor Defined message sub-type. Since Vendor code will be handling the TLV after the Vendor ID field is recognized, the remainder of the TLV value can be organized however the vendor wants. But it is desirable for a vendor to be able to define multiple different vendor messages and to keep track of different versions of its vendor defined messages. Thus, it is recommended that the vendor assigns a Sub-Type value for each vendor message that it defines different from other Sub-Type values that vendor has used. Also, when modifying a vendor defined message in a way potentially incompatible with a previous definition, the vendor shouldincrease the value it is using in the Sub-Type-Version field. 8. Implementation Status This section is not intended to appear in any resulting RFC. It discusses the status of implementations that have provided information and the testing of this protocol at the time of posting of this Internet-Draft, and is based on the proposal in [RFC7942] ("Improving Awareness of Running Code: The Implementation Status Section"). The description of implementations in this section is intended to assist in processing drafts to RFCs. Please note that the listing of any individual implementation or test results here does not imply endorsement by the RFC Editor or the IETF. Furthermore, no effort has been spent to verify the information presented here that was supplied by contributors. This is not intended as, and must not be construed to be, a catalog of available implementations or their testing or features. Readers are advised to note that other implementations may exist. According to [RFC7942], "this will allow reviewers ... to assign due consideration to documents that have the benefit of running code, which may serve as evidence of valuable experimentation and feedback that have made the implemented protocols more mature.". 8.1. Implementations Information on three S-CUSP implementations appears below. Hu, et al. Expires November 24, 2019 [Page 108] Internet-Draft S-CUSP for BNG May 2019 8.1.1. Huawei Technologies Name: Cloud-based BNG. Maturity: Production. Coverage: According to S-CUSP protocol. Contact information: Zhouyi Yu: yuzhouyi@huawei.com Date: 2018-11-01 8.1.2. ZTE Name: ZXR10 V6000 vBRAS Maturity: Production Coverage: According to S-CUSP protocol. Contact information: Yong Chen: 10056167@zte.com.cn Huaibin Wang: 10008729@zte.com.cn Date: 2018-12-01 8.1.3. H3C Name: CUSP protocol for BRAS Control Plane and User Plan Separation Maturity: Research Coverage: According to S-CUSP protocol Contact information: mengdan@h3c.com; liuhanlei@h3c.com Date: 2019-1-30 8.2. Hackathon Successful use of the protocol at the IETF-102 Hackathon, Montreal, Quebec, in 2018. Hackathon Project: Control Plane and User Plane Separation BNG control channel Protocol (CUSP) Hu, et al. Expires November 24, 2019 [Page 109] Internet-Draft S-CUSP for BNG May 2019 Champions: Zhenqiang Li, Michael Wang Report: See github.com/IETF-Hackathon/ietf102-project-presentations/ blob/ master/IETF102-hackathon-presentation-CUSP.pptx 8.3. EANTC Testing EANTC (European Advanced Networking Test Center (www.eantc.de)) tested the Huawei implementation. Their summary was as follows: "EANTC tested advanced aspects of the Cloud-based Broadband Network Gateway (vBNG) with a focus on performance, scalability and high availability with up to 20 Million emulated subscribers. The solution performed very well across all test scenarios." See report at www.eantc.de/fileadmin/eantc/downloads/News/2018/EANTC- vBRAS- phase2.pdf 9. Summary of Major S-CUSP Codepoints 9.1. Message Types Type Name Section of this document ------ ----------- ------------------------ 0 Reserved 1 Hello 6.2.1. 2 Keepalive 6.2.2. 3 Sync_Request 6.2.3. 4 Sync_Begin 6.2.4. 5 Sync_Data 6.2.5. 6 Sync_End 6.2.6. 7 Update_Request 6.2.7. 8 Update_Response 6.2.8. 9 Report 6.4. 10 Event 6.3. 11 Vendor 6.6. 12-199 Unassigned 200 Addr_Allocation_Req 6.5.1 201 Addr_Allocation_Ack 6.5.2 202 Addr_Renew_Req 6.5.3 203 Addr_Renew_Ack 6.5.4 204 Addr_Release_Req 6.5.5 205 Addr_Release_Ack 6.5.6 206-254 Unassigned 255 Reserved Hu, et al. Expires November 24, 2019 [Page 110] Internet-Draft S-CUSP for BNG May 2019 9.2. TLV Types Type Name Usage Description ----- ------------ -------------------------- 1 BAS Function Enabler Carry the BNG accesss functions to be enabled or disabled on specified interface(s). 2 Basic Subscriber Carry the basic information about a BNG subscriber. 3 PPP Subscriber Carry the PPP information about a BNG subscriber. 4 IPv4 Subscriber Carry the IPv4 information about a BNG subscriber. 5 IPv6 Subscriber Carry the IPv6 information about a BNG subscriber. 6 Subscriber Policy Carry the the policy information applied to a BNG subscriber. 7 IPv4 Routing Carry the IPv4 network routing information. 8 IPv6 Routing Carry the IPv6 network routing information. 9 IPv4 Static Subscriber Carry the static BNG subscriber information. 10 IPv6 Static Subscriber Carry the static BNG subscriber information. 11 L2TP-LAC Subscriber Carry the L2TP LAC subscriber information. 12 L2TP-LNS Subscriber Carry the L2TP LNS subscriber information. 13 L2TP-LAC Tunnel Carry the L2TP LAC tunnel information. 14 L2TP-LNS Tunnel Carry the L2TP LNS tunnel information. 15 Subscriber CGN Port Range Carry the public IPv4 address and the related port range of a BNG subscriber. 16-99 unassigned 100 Hello Used for version and Keep Alive timers negotiation. 101 Error Information Carried in the Ack of a control message, carries the processing result, success, or error. 102 Keep Alive Carried in the Hello message for Keep alive timers negotiation. 102-199 unassigned 200 Interface Status Interfaces status reported by the UP including physical interfaces, sub-interfaces, Hu, et al. Expires November 24, 2019 [Page 111] Internet-Draft S-CUSP for BNG May 2019 trunk interfaces, and tunnel interfaces. 201 Board Status Board information reported by the UP including the board type and in-position status. 202-299 unassigned 300 Subscriber Traffic Statistics User traffic statistics. 301 Subscriber Detection Result User detection result information. 302 Session Update Response The processing result of a subscriber session update. 303-299 unassigned 400 Address Allocation Request Request address allocation. 401 Address Allocation Response Address allocation response. 402 Address Renewal Request Request for address lease renewal. 403 Address Renewal Response Response to a request for extending an IP address lease. 404 Address Release Request Request to release the address. 405 Address Release Response Ack of a message releasing an IP address. 406-1023 unassigned 1024 Vendor As implemented by vendor. 1025-4095 unassigned 9.3. TLV Operation Codes Code Operation ---- ---------- 0 - reserved 1 Update 2 Delete 3-15 - unassigned 9.4. Sub-TLV Types Hu, et al. Expires November 24, 2019 [Page 112] Internet-Draft S-CUSP for BNG May 2019 Type Name Reference ----- ------------------ --------------- 0 - reserved 1 VRF Name 7.3.1 2 Ingress-QoS-Profile 7.3.1 3 Egress-QoS-Profile 7.3.1 4 User-ACL-Policy 7.3.1 5 Multicast-ProfileV4 7.3.1 6 Multicast-ProfileV6 7.3.1 7 Ingress-CAR 7.3.2 8 Egress-CAR 7.3.3 9 NAT-Instance 7.3.1 10 Pool-Name 7.3.1 11 If-Desc 7.3.4 12 If-Desc 7.3.5 13-64534 - unassigned 65535 -reserved 9.5. Error Codes Hu, et al. Expires November 24, 2019 [Page 113] Internet-Draft S-CUSP for BNG May 2019 Code Name Remarks -------- ------- -------- 0 Success Success 1 Failed Failure. The reason is not classified. 2 TLV-Unknown The TLV type cannot be identified. 3 TLV-Length The TLV length is abnormal. 4 TLV-Value The TLV value is abnormal 5-999 - unassigned Unassigned basic error codes. 1000 - reserved 1001 Version-Mismatch The version negotiation fails. Terminate. The subsequent service processes corresponding to the UP are suspended. 1002-1999 - unassigned Unassigned error codee for version negotiation 2000 - reserved 2001 Synch-NoReady The data to be smoothed is not ready. 2002 Synch-Unsupport The request for smooth data is not supported. 2003-2999 - unassigned Unassigned data synchronization error codes. 3000 - reserved 3001 Pool-Mismatch The corresponding address pool cannot be found. 3002 Pool-Full The address pool is fully allocated and no address segment is available. 3003 Subnet-Mismatch The address pool subnet cannot be found. 3004 Subnet-Conflict Subnets in the address pool have been classified into other clients. 3005-3999 - unassigned Unassigned error codes for address allocation. 4000 - reserved 4001 Update-Fail-No-Res The forwarding table fails to be delivered because the forwarding resources are insufficient. 4002 QoS-Update-Success The QoS policy takes effect. 4003 QoS-Update-Sq-Fail Failed to process the queue in the QoS policy. 4004 QoS-Update-CAR-Fail Processing of the CAR in the QoS policy fails. 4005 Statistic-Fail-No-Res Statistics processing failed due to insufficient statistics resources. 4006-4999 - unassigned forwarding table delivery error codes. 5000-4294967295 - reserved Hu, et al. Expires November 24, 2019 [Page 114] Internet-Draft S-CUSP for BNG May 2019 10. IANA Considerations IANA is requested to assign a service name and port for BNG S-CUSP as follows: Service Port Transport Name Number Protocol Description Reference ------- ------ --------- ------------- --------------- S-CUSP TBD1 TCP Control-plane and [this document] User-plane Separation Protocol 11. Security Considerations The Service, Control, and Management Interfaces between the CP and UP might be across the general Internet or other hostile environment. Thus, appropriate protections must be implemented to provide integrity, authenticity, and secrecy of traffic over those interfaces. Whether such protection is used is an operator decision. The S-CUSP messages do not provide security. Thus, if these messages are exchanged in an environment where security is a concern, that security must be provided by another protocol such as TLS 1.3 [RFC8446], DTLS, or IPSEC. However, such security protocols need not always be used and lesser security precautions might be appropriate because, in some cases, the communication between the CP and UP is in a more benign environment. 12. Contributors Hu, et al. Expires November 24, 2019 [Page 115] Internet-Draft S-CUSP for BNG May 2019 Zhouyi Yu Huawei Technologies Email: yuzhouyi@huawei.com Chengguang Niu Huawei Technologies Email: chengguang.niu@huawei.com Zitao Wang Huawei Technologies Email: wangzitao@huawei.com Jun Song Huawei Technologies Email: song.jun@huawei.com Dan Meng H3C Technologies No.1Lixing Center?No.8 guangxun south stree, Chaoyang District, Bejing, 100102 China Email: mengdan@h3c.com Hanlei Liu H3C Technologies No.1Lixing Center?No.8 guangxun south stree, Chaoyang District, Bejing, 100102 China Email: hanlei_liu@h3c.com 13. Acknowledgements 14. Informative References [RFC793] Postel, J., "Transmission Control Protocol", STD 7, RFC 793, DOI 10.17487/RFC0793, September 1981, . [RFC1661] Simpson, W., Ed., "The Point-to-Point Protocol (PPP)", STD 51, RFC 1661, DOI 10.17487/RFC1661, July 1994, . Hu, et al. Expires November 24, 2019 [Page 116] Internet-Draft S-CUSP for BNG May 2019 [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, DOI 10.17487/RFC2131, March 1997, . [RFC2661] Townsley, W., Valencia, A., Rubens, A., Pall, G., Zorn, G., and B. Palter, "Layer Two Tunneling Protocol "L2TP"", RFC 2661, DOI 10.17487/RFC2661, August 1999, . [RFC3022] Srisuresh, P. and K. Egevang, "Traditional IP Network Address Translator (Traditional NAT)", RFC 3022, DOI 10.17487/RFC3022, January 2001, . [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, . [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and IETF Protocol and Documentation Usage for IEEE 802 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, October 2013, . [RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running Code: The Implementation Status Section", BCP 205, RFC 7942, DOI 10.17487/RFC7942, July 2016, . [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, . [TR-384] Broadband Forum, "Cloud Central Office Reference Architectural Framework", 2018. Appendix A. An Appendix Authors' Addresses Shujun Hu China Mobile 32 Xuanwumen West Ave, Xicheng District Beijing, Beijing 100053 Email: hushujun@chinamobile.com Hu, et al. Expires November 24, 2019 [Page 117] Internet-Draft S-CUSP for BNG May 2019 Donald Eastlake, 3rd Huawei Technologies 1424 Pro Shop Court Davenport, FL 33896 Email: d3e3e3@gmail.com Mach(Guoyi) Chen Huawei Technologies Email: mach.chen@huawei.com Fengwei Qin China Mobile 32 Xuanwumen West Ave, Xicheng District Beijing, Beijing 100053 Email: qinfengwei@chinamobile.com Zhenqiang Li China Mobile 32 Xuanwumen West Ave, Xicheng District Beijing, Beijing 100053 Email: lizhenqiang@chinamobile.com Tee Mong Chua Singapore Telecommunications Limited 31 Exeter Road, #05-04 Comcentre Podium Block Singapore City 239732 Email: teemong@singtel.com Daniel Huang ZTE Email: huang.guangping@zte.com.cn Hu, et al. Expires November 24, 2019 [Page 118]