Service Function Chaining Sunil Kumar Sinha Internet-Draft Infinite Computing Solutions Intended status: Informational Amardeep Sinha Expires: December 18, 2018 Reliance Jio Infocomm Limited Harsh Vardhan Singh Chauhan Nokia Manish Srivastava Commscope Networks June 19, 2018 5G-Core System Split Bearer's FILTER for Dual Access draft-sfc-sinha-5g-bearer-filter-dual-access-00 Abstract This document attempts the case for new work that need to be developed for 5G user to improve faster download and upload of user's data via FILTER mechanism to be implemented at UPF user plane data for dual-access outlining the poor radio coverage issue. FILTER template governs the user data split at UPF with maintaining agreed PCC rules to achieve required throughput. 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 18, 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. 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. sinha Expires December 18, 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 Access and problem statement...........2 3.1 5G System architecture.....................................2 3.2 QoS........................................................3 3.3 Dual Connectivity..........................................4 3.4 Problem Statement..........................................4 4. 5G-Core System split bearer's FILTER for dual Access...........4 5. Security Considerations........................................6 6. IANA Considerations............................................6 7. Privacy Considerations ........................................6 8. Acknowledgements...............................................7 9. References.....................................................7 9.1. Normative References......................................7 9.2. Informative References....................................7 Authors' Addresses................................................7 1. Introduction 5G system have been evolved to server user in more efficient way of meeting higher download and upload of user data, whereas 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 a challenging for poor radio coverage (for both wi-fi and RAN). Hence re-engineering proposal has made in this document of 5G-Core entity UPF which is connected to Data Network handling user plane. 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 RFC 2119 [RFC2119]. 3. User data flow for Dual Access and problem statement 3.1 5G System architecture A simplified architectural diagram of 5G-system catering to both access type 3GPP and Wi-Fi being supported by UE is shown in Figure 1 below. sinha Expires December 18, 2018 [Page 2] Internet-Draft 5G Split Bearer Dual Access June 2018 +--------------------------------------------------------+ | +----------------------------+ | | | +------------------+ | | | | | | | | | | | |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 1 : Simplified 5G System Architecture for Multi 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 like WLAN or Wi-Fi. The N3IWF interface connect UE with 5G-core network via N2 and N3 interface. 3.2 QoS QFI is defined as QoS Flow ID is an 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. 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. sinha Expires December 18, 2018 [Page 3] Internet-Draft 5G Split Bearer Dual Access June 2018 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. 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. MeNB has full control to add, delete and HO(handover) of eNodeBs as and when needed. 3.4 Problem Statement Problem statement: In spite, in a Dual connectivity of 5G system, Master-gNB may have degrade radio condition and neither another Master-gNB nor secondary gNB available to support user data traffic and Secondary-gNB is available with sufficient radio resource. 4. 5G-Core System split bearer's FILTER for dual Access 4G system was designed such that it provides one default bearer for each APN type (service type). That is UE after attach procedure with access network, PGW create default data bearer of QCI=9 for data service. Again, if UE has voice capability, then it triggers new PDN connect request for APN=ims for voice & Video services, for which P-GW creates QCI=5 bearer as a default bearer. 5G system is designed to support dual access mechanism such that both 3GPP and non-3GPP access at same time. In this case P-GW needed to maintain two default bearers for each APN instead of one, as explained below. Please note: How an APN with same name to maintain two defaults bearers or APN name to be modified for each access type is out of scope of this document. However, details of setup procedure and call flow mechanism is beyond the scope of this draft, draft-sinha-5g-split-bearer-dual-access-00 can be referred. As shown in figure 2, for APN=data - PGW will create a default bearer QCI=9 for Wi-Fi access - PGW will create another default bearer QCI=9 for RAN access sinha Expires December 18, 2018 [Page 4] Internet-Draft 5G Split Bearer Dual Access June 2018 UPF +---------------------------+ | | | Default bearer QCI=9 | Access=Wifi +-----+ N3 | |<==================>| | APN=data |N3IWF|------------| |----------+ +-----+ | |<==================>| | | | | Dedicated bearer || | | Y1| | || | | | | || | +--------+ UE -----+ | FILTER | |Data N/W| | | || | +--------+ Uu| | || | | | | Dedicated bearer || | | +-----+ N3 | |<==================>| | | | RAN |------------| |----------+ +-----+ | |<==================>| | Access=RAN | Default bearer QCI=9 | APN=data | | +---------------------------+ Figure 2: 5G user for Data Service with default-bearer for each access-type and as shown in figure 3, for APN=ims - PGW will create a default bearer QCI=5 for Wi-Fi access - PGW will create another default bearer QCI=5 for RAN access UPF +---------------------------+ | | | Default bearer QCI=5 | Access=Wi-Fi +-----+ N3 | |<==================>| | APN=ims |N3IWF|------------| |----------+ +-----+ | |<==================>| | | | | Dedicated bearer || | | Y1| | || | | | | || | +--------+ UE -----+ | FILTER | | IMS N/W| | | || | +--------+ Uu| | || | | | | Dedicated bearer || | | +-----+ N3 | |<==================>| | | | RAN |------------| |----------+ +-----+ | |<==================>| | Access=RAN | Default bearer QCI=5 | APN=ims | | +---------------------------+ Figure 3: 5G user for IMS Service with default-bearer for each access-type Take for example IMS registration via SIP protocol, UE will send sip sinha Expires December 18, 2018 [Page 5] Internet-Draft 5G Split Bearer Dual Access June 2018 registration for RAN on QCI=5 and for Wi-Fi on separate QCI=5 Taking an example of voice call, one voice call established over RAN with QCI=1 and another voice call can be established in parallel over Wi-Fi over separate QCI=1. This dedicated bearer MUST be implemented with FILTER mechanism for data sharing. In case of poor radio coverage of RAN, for example, split bearer between RAN and Wi-Fi using this FILTER such that some part of audio packets are delivered to user via RAN and some via Wi-Fi, thus enhancing the user experience. SMF will be splitting the downlink packet in SPLIT mode via FILTER mechanism while maintaining PCC rule in tagged. Traffic FILTER mechanism is needed to be implemented between each QCI type for same APN, for only for DEDICATED bearer, not default bearer. This Filter mechanism will control traffic packet segmentation to be delivered on each of QCI. 5. Security Considerations Security considerations related to the 5G systems are discussed in [NGMN]. Due to the request for intrinsic realization of security such aspects must 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. 6. IANA Considerations None. 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 sinha Expires December 18, 2018 [Page 6] Internet-Draft 5G Split Bearer Dual Access June 2018 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 criticisms from Karthik Palaniswamy and Nagesh V. J. are respectfully acknowledged. 9. References 9.1. 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, . 9.2. Informative References [TS23.501] "3GPP TS23.501, System Architecture for the 5G System (Release 15)", 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. [TS23.502] "3Procedures for the 5G System", March 2018. [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. sinha Expires December 18, 2018 [Page 7] Internet-Draft 5G Split Bearer Dual Access June 2018 [ETSI GR NGP 004] "Next Generation Protocol (NGP): Evolved Architecture for mobility using. Identity Oriented Networks.",January2018. [ETSI GR NGP 001] "Next Generation Protocol (NGP); Scenario Definitions". ,May 2017 [NGMN] NGMN Alliance, "NGMN White Paper", February 2015. 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, Maharastra India Email: sinha.amardeep@gmail.com Harsh Vardhan Singh Chauhan Gwalior, MP Email: chauhan.harsh_vardhan@nokia.com Manish Srivastava Gr Sagarnivas, Central Jail Road, Bangalore, Karnataka, India Email: manishshree92@gmail.com sinha Expires December 18, 2018 [Page 8]