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DMM Working Group                                           P. Camarillo
Internet-Draft                                               C. Filsfils
Intended status: Informational                       Cisco Systems, Inc.
Expires: January 3, 2019                                        L. Bertz
                                                                  Sprint
                                                             A. Akhavain
                                           Huawei Canada Research Centre
                                                           S. Matsushima
                                                                SoftBank
                                                                D. Voyer
                                                             Bell Canada
                                                            July 2, 2018


            Segment Routing IPv6 for mobile user-plane PoCs
                draft-camarillo-dmm-srv6-mobile-pocs-00

Abstract

   This document describes the ongoing proof of concepts of
   [I-D.ietf-dmm-srv6-mobile-uplane] and their progress.

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
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   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 January 3, 2019.

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



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   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  M-CORD C3PO . . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  PoC phases  . . . . . . . . . . . . . . . . . . . . . . .   3
     3.2.  Activity report . . . . . . . . . . . . . . . . . . . . .   3
       3.2.1.  Phase 1 . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Open Air Interface  . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  PoC phases  . . . . . . . . . . . . . . . . . . . . . . .   4
     4.2.  Activity report . . . . . . . . . . . . . . . . . . . . .   5
   5.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Informative References  . . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   The [I-D.ietf-dmm-srv6-mobile-uplane] proposes SRv6 as userplane
   protocol for mobile networks.  As part of this work we have decided
   to create a series of PoCs with the objective to prove the viability
   and feasibility of such proposal.

   For this reason we have two ongoing PoCs using M-CORD C3PO and OAI,
   that are progressing towards a full implementation of the mechanisms
   described in such I-D.

   This I-D contains a formal definition of the PoCs and will summarize
   it's findings.  Anyone interested in participating in the ongoing
   PoCs or propose new ones is welcome to join us.

2.  Terminology

   This document adopts the terminology of
   [I-D.ietf-dmm-srv6-mobile-uplane].

   This document uses the terms N3, N6 and N9 interfaces, as well as UPF
   and gNB as refered to in [TS.23501].








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3.  M-CORD C3PO

   M-CORD <https://www.opennetworking.org/m-cord/> is an open-source
   project from ONF focused on building a cloud-native virtualized and
   dissagregated RAN and EPC.

   As part of the M-CORD project, the C3PO component is part of the NGIC
   (Next Generation Infrastructure Core)
   <https://gerrit.opencord.org/#/admin/projects/ngic>.

   The scope of this PoC is to extend the C3PO component to support
   natively SRv6 on the N6 and N9 interfaces and have SRv6-supported
   UPFs.

3.1.  PoC phases

   This PoC is divided in several phases:

   1.  SRv6 in transport network with no impact to EPC
   2.  SRv6 native in N6 interface (GiLAN) with SRv6 transport network
   3.  SRv6 native in N6 and N9 interfaces with N3 interworking
       mechanisms

3.2.  Activity report

   Phase 1 has been completed.  Ongoing development of phase 2.

3.2.1.  Phase 1

   We used FD.io VPP <https://fd.io/technology/> to simulate an SRv6
   transport network with three SRv6 routers in the N9 interface
   simulating a transport network.

   As part of this transport network, we run two simulations:

   In the first simulation we steered the IPv4/GTP traffic into an SR
   policy that encapsulated the packet with an SRv6 header containing
   two SIDs.

   In the second simulation we steered the IPv4/GTP traffic into an SR
   policy that removed the IPv4/GTP headers and placed the GTP header
   information (i.e.  TEID) into an SRv6 SID.  The last SID of the SR
   policy corresponds to an End.M.GTP4.E function, that decapsulates
   SRv6 traffic restoring the IPv4/GTP header.  The objective of the
   second simulation is to show the IPv4/GTP interworking mechanism via
   an uplink classifier behaving as SR-GW, as defined in Section 6.4 of
   [I-D.ietf-dmm-srv6-mobile-uplane] .




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   After Phase 1, we concluded that SRv6 as mobility transport network
   works fine, with an expected MTU overhead due to the original PDU
   encapsulation.  The IPv4/GTP interworking mechanism in the scope of
   phase 1 is also fully functional.  This mechanism will be further
   tested as the POC progresses and a native SRv6-based UPF is
   developed.

4.  Open Air Interface

   Open Air Interface (OAI) is an open-source software
   <http://www.openairinterface.org/?page_id=2762> that implements the
   3GPP stack.  OAI is composed of two major projects: OAI-RAN and OAI-
   CN.

   o  OAI-RAN implements the 4G LTE and 5G Radio Access Network.  Both
      the gNB as well as the UE are implemented.
   o  OAI-Core Network implements the 4G LTE Evolved Packet Core (EPC)
      and 5G Core Network.

   The scope of this PoC is to extend the OAI-RAN and OAI-CN components
   to support natively SRv6 on the N3 and N9 interfaces, and have
   SRv6-supported gNBs and UPFs.

4.1.  PoC phases

   The primary goal of this POC is to show SRv6 as a data plane
   replacement for GTP on both N3 and N9 interfaces.  The POC also aims
   to demonstrate a smooth migration path during deployment and
   transition period from IPv4-GTP and IPv6-GTP to an end to end SRv6
   data plane.

   The PoC functions within the existing OAI model.  OAI currently
   doesn't provide support for S5/S8 interface.  The implementation
   instead provides an integrated SGW and PGW S/PGW module and therefore
   there is no GTP tunnel between these two entities.  This limitation
   has an impact on the POC strategy and its implementation phases.

   This PoC is divided in several phases:

   1.-  N3 via SRv6 GW VNFs and no impact on 3GPP control plane.

        1.1.-  IPv4-GTP interworking
        1.2.-  IPv6-GTP interworking
   2.-  N3 via SRv6 eNB and S/PGW integrated modules and no impact on
        3GPP control plane.

        2.1.-  IPv4-GTP interworking
        2.2.-  IPv6-GTP interworking



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   3.-  N3 via SRv6 support for ID-LOC architecture

   Important notes:

   - The above phases and solution strategy can easily be extended to
     the N9 interface.  However, although the N9 interface is well
     within the scope of this PoC, the effort required to changes the
     OAI code base to support S5/S8 and separate SGW and PGW modules
     will push the project well beyond the timeline of this PoC and as
     such are not currently part of the PoC.
   - Support for service programming, TE, QoS, entropy, and other
     enhanced features are also within the scope of this PoC, but will
     also fall beyond the time line of this project and are not
     currently considered in this PoC.
   - The above items can be pulled back into the project based on demand
     and assistance from others.

4.2.  Activity report

   Development started.  Phase 1 has not yet been completed.

5.  Contributors

   Arun Rajagopal
   Sprint
   United States of America

   Email: Arun.Rajagopal@sprint.com

   Mark Bales
   Sprint
   United States of America

   Email: Mark.Bales@sprint.com

   Robert Butler
   Sprint
   United States of America

   Email: Robert.Butler@sprint.com

6.  Informative References









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   [I-D.filsfils-spring-srv6-network-programming]
              Filsfils, C., Li, Z., Leddy, J., daniel.voyer@bell.ca, d.,
              daniel.bernier@bell.ca, d., Steinberg, D., Raszuk, R.,
              Matsushima, S., Lebrun, D., Decraene, B., Peirens, B.,
              Salsano, S., Naik, G., Elmalky, H., Jonnalagadda, P., and
              M. Sharif, "SRv6 Network Programming", draft-filsfils-
              spring-srv6-network-programming-04 (work in progress),
              March 2018.

   [I-D.ietf-dmm-srv6-mobile-uplane]
              Matsushima, S., Filsfils, C., Kohno, M., Camarillo, P.,
              daniel.voyer@bell.ca, d., and C. Perkins, "Segment Routing
              IPv6 for Mobile User Plane", draft-ietf-dmm-srv6-mobile-
              uplane-01 (work in progress), March 2018.

   [TS.23501]
              3GPP, "System Architecture for the 5G System", 3GPP TS
              23.501 15.0.0, November 2017.

Authors' Addresses

   Pablo Camarillo Garvia
   Cisco Systems, Inc.
   Spain

   Email: pcamaril@cisco.com


   Clarence Filsfils
   Cisco Systems, Inc.
   Belgium

   Email: cf@cisco.com


   Lyle T Bertz
   Sprint
   United States of America

   Email: Lyle.T.Bertz@sprint.com


   Arashmid Akhavain
   Huawei Canada Research Centre
   Canada

   Email: arashmid.akhavain@huawei.com




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   Satoru Matsushima
   SoftBank
   Tokyo
   Japan

   Email: satoru.matsushima@g.softbank.co.jp


   Daniel Voyer
   Bell Canada
   Canada

   Email: daniel.voyer@bell.ca






































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