Service Function Chaining Sunil Kumar Sinha Internet-Draft Infinite Computing Solutions Intended status: Informational Amardeep Sinha Expires: December 9, 2018 Reliance Jio Infocomm Limited Amit Mishra Varsa Networks Yogesh Chandeshware Mavenier June 10, 2018 5G System Split Bearer for Dual-Access draft-sfc-sinha-5g-split-bearer-dual-access-00 Abstract This document attempts the case for new work that needs to be developed for 5G users to improve faster download and upload of user's data in a scenario of dual-access outlining the poor radio coverage issues. This document also outlines the faster user data mechanisum accompanying dual access capabilities of 5G user device via split bearer in case of a poor coverage. 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 December 9, 2018. Copyright Notice Copyright (c) 2018 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. sinha Expires December 9, 2018 [Page 1] Internet-Draft 5G Split Bearer Dual Access June 2018 Table of Contents: 1. Introduction...................................................2 2. Conventions and Terminology....................................2 3. User data flow for Dual Connectivity for Dual Access and problem statement..............................................2 3.1 5G System Architecture.....................................2 3.2 QoS........................................................4 3.3 Dual Connectivity..........................................5 3.4 Problem Statement..........................................5 4. Proposal of Split Bearer for dual access.......................5 5. IANA Considerations............................................7 6. Security Considerations........................................7 7. Privacy Considerations ........................................7 8. Acknowledgements...............................................7 9. References.....................................................7 9.1 Normative References.......................................7 9.2 Informative References.....................................8 Authors' Addresses................................................9 1. Introduction 5G system has been evolved to serve the user in more efficient way of meeting higher download and upload of user data, 5G Users accessing the network via wireline and wireless, in addition to this Residential Gateway RG and IoT support is also defined. Access and user experience is challenging for poor radio coverage (for both wi-fi and RAN) and the proposal in this document addresses the problem of poor coverage on either 3GPP or non-3GPP access with UE in dual-access mode. 2. Conventions and Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 3. User data flow for Dual Connectivity for Dual Access and problem statement 3.1 5G System Architecture A simplified 5G System architecture shown in Figure-1 in the case of UE in non-roaming scenario with RAN access(3GPP). User data of 5G system is delivered to user from Service or data network via interface N6 and N3 to UE. sinha Expires December 9, 2018 [Page 2] Internet-Draft 5G Split Bearer Dual Access June 2018 +-----------------------------+ | +-----------------+ | | | |N8 |N15 +------+ | | +----+ N13 +-----+ | | NSSF |---+ | | |AUSF|-------| UDM | | +------+ | | | +----+ +-----+ | | | | | | | N22| | | |N12 |N10 +-----+ N5 +----+ | | | +-+ | | PCF |------| AF | | | | | | +-----+ +----+ | | | | | | +-------+ N11 +---+ N7 | | AMF |------------|SMF|-------+ +-------+ +---+ | | |N2 |N4 | | | | Uu +-----+ N3 +---+ N6 +-------------+ UE--------------| RAN |-------------|UPF|--------| Service N/W | +-----+ +---+ +-------------+ Figure 1 : Simplified 5G System Architecture for RAN access For the clarity in the current document proposal, multiple node/ function like UDSF, NRF, and interfaces N9, N14 are not shown. 5G System supporting UE access to the network function and services via non-3GPP is shown in Figure-2. An example of such access are like WLAN or Wi-Fi. The N3IWF interface connect UE with 5G core network via N2 and N3 interface. +-----------------------------+ | +-----------------+ | | | |N8 |N15 +------+ | | +----+ N13 +-----+ | | NSSF |---+ | | |AUSF|-------| UDM | | +------+ | | | +----+ +-----+ | | | | | | | N22| | | |N12 |N10 +-----+ N5 +----+ | | | +-+ | | PCF |------| AF | | | | | | +-----+ +----+ | | | | | | +-------+ N11 +---+ N7 | | AMF |------------|SMF|-------+ +-------+ +---+ | | |N2 |N4 | | | | Y1 +--+ Y2 +-----+ N3 +---+ N6 +-------------+ UE-----|AP|-----|N3IWF|-------------|UPF|--------| Service N/W | +--+ +-----+ +---+ +-------------+ Figure 2 : Simplified 5G System Architecture for Wi-Fi access sinha Expires December 9, 2018 [Page 3] Internet-Draft 5G Split Bearer Dual Access June 2018 A complete architectural diagram of 5G System catering to both access type being supported by UE is shown in Figure 3. +--------------------------------------------------------+ | +----------------------------+ | | | +------------------+ | | | | | | | | | | | |N8 |N15 | | | | | | | | +------+ | | +------+ N13 +---+ | | | | NSSF |--+ | | | AUSF |-------|UDM| | | | +------+ | | | +------+ +---+ | | | | | | | | | | | | | | | | | | N3| N22| | | |N12 N10| +---+ N5 +--+ | | | | | +---+ | |PCF|------|AF| | | | | | | | +---+ +--+ | | | | | | | | | +-----+ +---------+ +-----+ | | | RAN |------| AMF |-----------| SMF |----+ | +-----+ N2 +---------+ N11 +-----+ N7 | | | | | +--+ Uu | | | | | |-----+ |N2 |N4 | |UE| | | | | |-----+ | | | +--+ Y1 | +----------+ +---------+ | | | | | | | | | +--------+ N3 +-----+ N6 +-------------+ | |AP+N3IWF|---------------| UPF |------| Service N/W | | +--------+ +-----+ +-------------+ | | | +-------------------------------+ Figure 3 : Simplified 5G System Architecture for Multi access 3.2 QoS QFI is defined as Qos Flow ID is a identity to QoS flow in the 5G system. All data traffic within a PDU session are each labelled or identified by QFI, implies same QFI labelled data flow will receives same traffic forwarding treatment like scheduling, priority, etc. QoS /Data flow is via N3(and N3 and N9) interface, being encapsulated end-to-end. This flow is controlled by SMF, who provides QoS profile during session establishment to R(AN) and provide the PDR to the UPF. Please Note that like 4G system, default QoS flow is applied to each PDU session and retain till lifetime span of connectivity. In case of non-3GPP access QFI is delivered to N3IWF entity (or NG-RAN) for every time User Plane of the PDU session is established, modified or activated. sinha Expires December 9, 2018 [Page 4] Internet-Draft 5G Split Bearer Dual Access June 2018 3.3 Dual Connectivity Dual connectivity (DC) functionality support the network to make use of additional radio resource to achieve required throughput in downlink and uplink of user data. This was introduced in 4G system support 5G data speed by addition of dual connectivity of UE with eNBs, master eNB and secondary eNB and /or eNodeB in congestion with gNB. This is achieved by addition of secondary eNodeB to the Master eNodeB. Master eNB has full control to add, delete and HO(handover) of eNodeBs as and when needed.[20160157293] 3.4 Problem Statement Problem statement: Inspite of dual access 5G users radio condition capabilities degrade on either of the access types and the associated user experience on that access type becomes a challenge. 4. Proposal of Split Bearer for dual access The solution proposed in this document to solve the problem of degrade radio condition on the either of the access type at UE and bearer offloading to other access-type. Bearer split among RAN and Wifi referring to Fig-4. Trigger for split bearer of bearer can originate from other of access type RAN or wifi. - In the example given in figure-4 there is a degrade in radio condition at RAN access of user. And at the same time 5G user also have wi-fi access registered. - Based on measurement report from UE, gNB (RAN) take decision for partial Handover. gNB asked for UECapabilitys to check availability of other access type. - Taking inputs on UECapabilities response about the availability of other access type, gNB process for Split bearer with other access type - gNB(RAN) triggers split bearer request for Wi-Fi access to AMF and also includes user data traffic template FILTER. FILTER: FILTER is a user data delivery template defined by NG-RAN for the 5G-core UPF to implement and execute, without super imposing on the PCC rule. - If offload of complete user data traffic is needed, then FILTER value MUST be empty/NULL. sinha Expires December 9, 2018 [Page 5] Internet-Draft 5G Split Bearer Dual Access June 2018 +--+ +-----+ +-----+ +---+ +---+ +---+ |UE| | gNB | |N3IWF| |AMF| |SMF| |UPF| +--+ +-----+ +-----+ +---+ +---+ +---+ | | | | | | |<==User Data==>|<==============User Data==============>| | | | | | | | Measurement Control | | | | |<--------------| | | | | | | | | | | | Measurement | | | | | |-------------->| | | | | | Report | | | | | | +-------------+ | | | | | | HO Decision | | | | | | +-------------+ | | | | | | | | | | |UEAccessCapability | | | | |<--------------| | | | | | | | | | | |UE-Wifi Access Report | | | | |-------------->| | | | | | | | | | | | +-------------+ | | | | | |SPLIT Bearer | | | | | | |Dual Access | | | | | | +-------------+ | | | | | | | | | | | Split-Bearer Request to Wifi | | | |------------------->| | | | | (FILTER) | | | | | | | | | | | | +---------------------+ | | | | |HO procedure to N3IWF| | | | | | + FILTER | | | | | +---------------------+ | | | | | | | | | | | +-------------------------+ | | | |Bearer Update + FILTER | | | | +-------------------------+ || | | | | | | | | | |<=Split Bearer with Wifi=>|<========Data==============>| | | | | | | |<=Split Beare=>|<========Data=========================>| | with RAN | | | | | Figure 4 : Bearer Offloading Dual-Connectivity with dual access - If split of user data traffic is needed, then FILTER SHOULD have required template according to which partial user data traffic is split between RAN and Wi-Fi by UPF on N3 interface. sinha Expires December 9, 2018 [Page 6] Internet-Draft 5G Split Bearer Dual Access June 2018 5. IANA Considerations None. 6. Security Considerations Security considerations related to the 5G systems are discussed in [NGMN]. Due to the request for intrinsic realization of security such aspects have to be considered by design for architecture and protocols. Especially as a joint usage of resources and network functions by different separate logical network slices (e.g. in terms of virtual network functions) seems to be inevitable in the framework of 5G the need for strong security measures in such an environment is a major challenge. 7. Privacy Considerations Support of full privacy of the users (customers and tenants / end service providers) is a basic feature of the next generation trusted and reliable communications offering system. Such a high degree of ensured privacy shall be reflected in the proposed architecture and protocol solutions. Especially as Identifiers and mapping of locators to them are addressed some privacy concerns arise. Mobility solutions tend to expose unique identifiers. A solution inside the mobile network exposes these identifiers to the network operator, which is not a big deal since the network operator already has information about the device's location. In contrast, an IP level solution exposes both the identifiers and the locations at the IP layer. That means that web sites, for example, can now track the device's successive locations by watching the IP address. Solutions such as transporting the identifiers not as part of the IP header should be considered. 8. Acknowledgements This work has been partially performed in the framework of the cooperation Config. Contributions of the project partners are gratefully acknowledged. The project consortium is not liable for any use that may be made of any of the information contained therein. Comments, constructive critisms from Karthik Palaniswamy and Nagesh V. J. are respectfully acknowledged. 9. References 9.1. Normative References sinha Expires December 9, 2018 [Page 7] Internet-Draft 5G Split Bearer Dual Access June 2018 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . 9.2. Informative References [20160157293] "Method to Provide Dual Connectivity Using LTE Master eNodeB and Wi-Fi Based Secondary eNodeB", June,2016. [TS23.228] "IP Multimedia Subsystem (IMS)", March 2018. [TR38.801] "Study on new radio access technology: Radio access architecture and interfaces", March 2017. [TR23.793] "Study on Access Traffic Steering, Switch and Splitting support in the 5G system architecture.", April 2018. [TR23.793] "Study on Access Traffic Steering, Switch and Splitting support in the 5G system architecture.", April 2018. [ETSI GR NGP 004] "Next Generation Protocol (NGP):Evolved Architecture for mobility using. Identity Oriented Networks.",January 2018 [ETSI GR NGP 001] "Next Generation Protocol (NGP); Scenario Definitions". ,May 2017 [TS23.501] "3GPP TS23.501, System Architecture for the 5G System (Release 15)", March 2018. [TS23.502] "3Procedures for the 5G System", March 2018. [TS36.300] "3GPP TS36.300, Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description", March 2018. [NGMN] NGMN Alliance, "NGMN White Paper", February 2015. sinha Expires December 9, 2018 [Page 8] Internet-Draft 5G Split Bearer Dual Access June 2018 Authors' Addresses Sunil Kumar Sinha FF-01, Rainbow Residency, Green Glan layout, Bellandur, Bangalore Karnataka, India Email: sunilkumarsinha9@gmail.com Amardeep Sinha C-1003, Yashodeep Heights, Sec-29C, Airoli, Navi-Mumbai, Maharashtra, India Email: sinha.amardeep@gmail.com Amit Mishra Flat No: 208, 16th Block, Sun City Appartments, Iblur Junction, Sarjapur Signal, Bengaluru, India Email: amit.j.mishra@gmail.com Yogesh Chandeshware Shasi Nivas, 1st Street , F main, Vijaya Vank Colony Extn, Banaswadi, Bangalore Karnataka, India Email: yogeshjc017@gmail.com sinha Expires December 9, 2018 [Page 9]