PCE Working Group H. Li Internet-Draft A. Wang Intended status: Standards Track China Telecom Expires: November 25, 2021 H. Chen Futurewei C. Zhu ZTE Corporation May 24, 2021 PCEP Extension for Multicast Management draft-li-pce-pcep-extension-multicast-management-00 Abstract This document describes extensions to Path Computation Element (PCE) communication Protocol (PCEP) for supporting multicast service management. 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 25, 2021. Copyright Notice Copyright (c) 2021 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 Li, et al. Expires November 25, 2021 [Page 1] Internet-Draft PCEP Extension for Multicast Management May 2021 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions used in this document . . . . . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Overview of Using PCE for multicast service management . . . 4 5. PCEP message . . . . . . . . . . . . . . . . . . . . . . . . 5 5.1. PCRpt message . . . . . . . . . . . . . . . . . . . . . . 5 5.2. PCUpd message . . . . . . . . . . . . . . . . . . . . . . 6 6. Object formats . . . . . . . . . . . . . . . . . . . . . . . 7 6.1. Multicast source registration object . . . . . . . . . . 7 6.1.1. IPv4 multicast TLV . . . . . . . . . . . . . . . . . 7 6.1.2. IPv6 multicast TLV . . . . . . . . . . . . . . . . . 9 6.2. Multicast receiver information object . . . . . . . . . . 10 6.3. Forwarding indication object . . . . . . . . . . . . . . 11 7. Deployment Considerations . . . . . . . . . . . . . . . . . . 11 8. Security Considerations . . . . . . . . . . . . . . . . . . . 12 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 10. Contributor . . . . . . . . . . . . . . . . . . . . . . . . . 12 11. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 12 12. Normative References . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 1. Introduction Currently, multicast management information is mainly signaled by PIM [RFC2362] or BGP [RFC6514], which have some limitations in the deployment and process. [RFC4655] defines a stateful PCE to be one in which the PCE maintains "strict synchronization between the PCE and not only the network states (in term of topology and resource information), but also the set of computed paths and reserved resources in use in the network." [RFC8231] specifies a set of extensions to PCEP to support state synchronization between PCCs and PCEs. [RFC8279] defines a Bit Index Explicit Replication (BIER) architecture where all intended multicast receivers are encoded as a bitmask in the multicast packet header within different encapsulations such as described in [RFC8296] . A router that receives such a packet will forward the packet based on the bit position in the packet header towards the receiver(s) following a precomputed tree for each of the bits in the packet. Each receiver is represented by a unique bit in the bitmask. Li, et al. Expires November 25, 2021 [Page 2] Internet-Draft PCEP Extension for Multicast Management May 2021 This document spceifies PCEP protocol extensions to optimize the implementation of multicast source registration/revocation, receiver automatic discovery,and forwarding control of multicast data by using PCEP messages to transmit multicast management signaling, combining with the forwarding characteristics of BIER. 2. Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 3. Terminology The following terms are used in this document: o BFR-id: BFR Identifier. It is a number in the range [1,65535] o BGP: Border Gateway Protocol o BIER: Bit Index Explicit Replication o BIFT: Bit Index Forwarding Table o FI: Forwarding indication o IGMP: Internet Group Management Protocol o IGP: Interior Gateway Protocols o MLD: Multicast Listener Discover o MRI: Multicast Receiver Information o MSR: Multicast Source Registration o PCC: Path Computation Client o PCE: Path Computation Element o PCEP: PCE communication Protocol o PIM: Protocol Independent Multicast Li, et al. Expires November 25, 2021 [Page 3] Internet-Draft PCEP Extension for Multicast Management May 2021 4. Overview of Using PCE for multicast service management Multicast service management includes multicast source registration information management, multicast receiver information management and multicast data forwarding control. Multicast source registration information includes registration and processing of multicast group and source information. Multicast receiver information includes requesting multicast group, multicast source and VPN information. Multicast data forwarding control includes BitString calculation and data forwarding. PCRpt message and PCUpd message, described in [RFC8231], are used in the multicast service management process. The specific implementation process is as follows: +------------------+ + Controller + +-----------+ PCE +----------+ | +--------^---------+ | | | | | 1 | 4 +--------+ | 3 | -----------+ R3 +------------ | | / +--------+ \ | | / \ | +-------+ +--+ +--+ +--+ +--+ 2 +--------+ |Sourece|-----|R1+----------+R5+----------+R6+---------+R7|-----|Receiver| +-------+ +--+ +--+ +--+ +--+ +--------+ | | | +--+ +--+ | +------------+R2+----------+R4+-----------+ +--+ +--+ Figure 1: Example Multicast management Topology with PCE(controller as PCE) Step 1 : The source-side PCC R1 sends multicast group and source information to the controller about multicast information registration via PCRpt message. Then the controller stores the multicast registration information into the database. Step 2 : Receivers send IGMP/MLD messages to the receiver-side PCC R7 requesting to join/leave a multicast group. Li, et al. Expires November 25, 2021 [Page 4] Internet-Draft PCEP Extension for Multicast Management May 2021 Step3 : The receiver-side PCC R7 converts the IGMP/MLD messages into PCRpt message and send it to the controller. The information of IGMP Membership Report messages should be convert to IPv4 Multicast TLV. The information of MLD Membership Report messages should be convert to IPv6 Multicast TLV. These TLVs are defined in section 6.1. Furthermore, PCC should not send PCRpt message with join information to the controller if the receiver is not the first one to joining the multicast group. PCC should not send PCRpt message with leaving information to the controller if the receiver is not the last one to leave the multicast group. Step 4 : If the multicast group and multicast source information requested by the receiver has registered, the controller calculates the forwarding path and sends it to the source-side PCC R1 via PCUpd message in the form of BitString to control data forwarding. The source-side PCC encapsulates BIER header and forwards them based on BIFT and BitString when receving multicast packets. This document specifies PCEP protocol extensions for multicast group management, including multicast source registration (MSR) object, multicast receiver information (MRI) object, forwarding indication (FI) object, two TLVs and extensions to PCRpt message and PCUpd message. 5. PCEP message 5.1. PCRpt message A PCC should include the MSR object (see Section 6.1) in the PCRpt message if the PCC wants to register multicast source information with the PCE. And a PCC MAY include the MRI object (see Section 6.2) in the PCRpt message if the PCC wants to send multcast join messages to a PCE. The definition of the PCRpt message from [RFC8231] is extended to optionally include the MSR object and the MRI object after the path object. The encoding from [RFC8231] will become: Li, et al. Expires November 25, 2021 [Page 5] Internet-Draft PCEP Extension for Multicast Management May 2021 ::= Where: ::= [] ::= [] [] [] Where: is as per [RFC8231] and the LSP and SRP object are also defined in [RFC8231]. 5.2. PCUpd message A PCE should include the FI object in the PCUpd message (see Section 6.3) if the PCE wants to send the BitString to the PCC to indicate the path of multicast data packets forwarding for PCC. The definition of the PCUpd message from [RFC8231] is extended to optionally include the FI object after the path object. The encoding from [RFC8231] will become: ::= Where: ::= [] ::= [] Where: is as per [RFC8231] and the LSP and SRP object are also defined in [RFC8231]. Li, et al. Expires November 25, 2021 [Page 6] Internet-Draft PCEP Extension for Multicast Management May 2021 6. Object formats 6.1. Multicast source registration object The MSR object is optional and specifies multicast group and source information in multicast registration information management. The MSR Objcet should be carried within a PCReq message sent by the PCC to the PCE in muticast scenarios. MSR Object-Class is TBD1. MSRObject-Type is 1. The format of the MSR objcet body is: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Subdomain-id | BFR-ID | BSL |Flags|R| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Optional TLVs | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: MSR Object Body Format Subdomain-id(8 bits): Unique value identifying the BIER subdomain. BFR-ID (16 bits): Identification of BFR in a subdomain. BSL(BitString Length, 4 bits): encodes the length in bits of the BitString as per[RFC8296] , the maximum length of the BitString is 7, it indicates the length of BitString is 4096.It is used to refer to the number of bits in the BitString. Flags (3 bits): This field MUST be set to zero on transmission and MUST be ignored on receipt. R (Register flag - 1 bit): The R flag set to 1 indicates that the PCC is registering multicast information to the PCE. The R flag set to 0 indicates that the PCC revokes the register. The specific format of two TLVs are as follows: 6.1.1. IPv4 multicast TLV The format of the IPv4 Multicast TLV is shown in the following figure: Li, et al. Expires November 25, 2021 [Page 7] Internet-Draft PCEP Extension for Multicast Management May 2021 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=TBD2 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RD | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Multicast Source address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Number of Groups(N) | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Multicast Group address [1] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | . | | . | | . | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Multicast Group address [N] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Auxliary Data | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: IPv4 Multicast TLV Format The type of the TLV is TBD. RD(Route Distinguisher(8 bytes): indicates the VPN which the receiver used. IPv4 Multicast Source Address(32 bits): contains IPv4 address of the multicast source requested. Number of Groups(16 bits): indicates the number of group requested. Reserved (16 bits): This field MUST be set to zero on transmission and MUST be ignored on receipt. IPv4 Multicast Group address [N](32 bits): contains IPv4 address of the multicast group want to join or leave. Auxliary Data(32 bits): contains functional data such as authentication information. Li, et al. Expires November 25, 2021 [Page 8] Internet-Draft PCEP Extension for Multicast Management May 2021 6.1.2. IPv6 multicast TLV The format of the IPv6 Multicast TLV is shown in the following figure: 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=TBD3 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RD | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | IPv6 Multicast Source address | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Number of Groups(N) | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | IPv6 Multicast Group address [1] | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | . | | . | | . | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | IPv6 Multicast Group address [N] | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Auxliary Data | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4: IPv6 Multicast TLV Format The type of the TLV is TBD. RD(Route Distinguisher(8 bytes): indicates the VPN which the receiver used. IPv6 Multicast Source Address(16 bytes): contains IPv6 address of the multicast source requested. Number of Groups(16 bits): indicates the number of group requested. Li, et al. Expires November 25, 2021 [Page 9] Internet-Draft PCEP Extension for Multicast Management May 2021 Reserved (16 bits): This field MUST be set to zero on transmission and MUST be ignored on receipt. IPv6 Multicast Group address [N](16 bytes): contains IPv6 address of the multicast group want to join or leave. Auxliary Data(32 bits): contains functional data such as authentication information. 6.2. Multicast receiver information object The MRI object is optional and specifies the access information of receivers for matching the multicast registration information in multicast access management. The MRI Objcet can be carried within a PCReq message sent by the PCC to the PCE in muticast scenarios. MRI Object-Class is TBD4. MRI Object-Type is 1. The format of the MSR objcet body is: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Subdomain-id | BFR-ID | BSL |Flags|S| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Optional TLVs | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5: MRI Object Body Format Subdomain-id(8 bits): Unique value identifying the BIER subdomain. BFR-ID (16 bits): Identification of BFR in a subdomain. BSL(BitString Length, 4 bits): encodes the length in bits of the BitString as per[RFC8296] , the maximum length of the BitString is 7, it indicates the length of BitString is 4096.It is used to refer to the number of bits in the BitString. Flags (3 bits): This field MUST be set to zero on transmission and MUST be ignored on receipt. S (Subscribe flag - 1 bit): The S flag set to 1 indicates that the PCC delivers the message requesting to join the PCE. The S flag set to 0 indicates that the PCC delivers the message requesting to leave to the PCE. Li, et al. Expires November 25, 2021 [Page 10] Internet-Draft PCEP Extension for Multicast Management May 2021 6.3. Forwarding indication object The FI object is optional and used to indicate the path of multicast data packets forwarding for headend in the form of BitString. The FI Objcet can be carried within a PCUpd message sent by the PCE to the PCC in muticast scenarios. FI Object-Class is TBD5. BitString Object-Type is 1. The format of the FI objcet body is: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Subdomain-id | SI | BSL | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BitString (first 32 bits) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | . | | . | | . | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BitString (last 32 bits) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 6: FI Object Body Format Subdomain-id(8 bits): Unique value identifying the BIER subdomain. SI (Set Identifier, 8 bits): encoding the Set Identifier used in the encapsulation for this BIER subdomain for this BitString length.. BSL(BitString Length, 4 bits): encodes the length in bits of the BitString as per[RFC8296] , the maximum length of the BitString is 7, it indicates the length of BitString is 4096.It is used to refer to the number of bits in the BitString. Reserved (12 bits): This field MUST be set to zero on transmission and MUST be ignored on receipt. BitString(Variable length): indicates the path of multicast data packets forwarding for headend. 7. Deployment Considerations TBD Li, et al. Expires November 25, 2021 [Page 11] Internet-Draft PCEP Extension for Multicast Management May 2021 8. Security Considerations TBD 9. IANA Considerations TBD 10. Contributor TBD 11. Acknowledgement TBD 12. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC2362] Estrin, D., Farinacci, D., Helmy, A., Thaler, D., Deering, S., Handley, M., Jacobson, V., Liu, C., Sharma, P., and L. Wei, "Protocol Independent Multicast-Sparse Mode (PIM-SM): Protocol Specification", RFC 2362, DOI 10.17487/RFC2362, June 1998, . [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, DOI 10.17487/RFC4655, August 2006, . [RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP Encodings and Procedures for Multicast in MPLS/BGP IP VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path Computation Element Communication Protocol (PCEP) Extensions for Stateful PCE", RFC 8231, DOI 10.17487/RFC8231, September 2017, . Li, et al. Expires November 25, 2021 [Page 12] Internet-Draft PCEP Extension for Multicast Management May 2021 [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., Przygienda, T., and S. Aldrin, "Multicast Using Bit Index Explicit Replication (BIER)", RFC 8279, DOI 10.17487/RFC8279, November 2017, . [RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation for Bit Index Explicit Replication (BIER) in MPLS and Non- MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January 2018, . Authors' Addresses Huanan Li China Telecom Beiqijia Town, Changping District Beijing, Beijing 102209 China Email: lihn6@foxmail.com Aijun Wang China Telecom Beiqijia Town, Changping District Beijing, Beijing 102209 China Email: wangaj3@chinatelecom.cn Huaimo Chen Futurewei Boston USA Email: Huaimo.chen@futurewei.com Chun Zhu ZTE Corporation 50 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China Email: zhu.chun1@zte.com.cn Li, et al. Expires November 25, 2021 [Page 13]