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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 DMM Working Group P. Camarillo 3 Internet-Draft C. Filsfils 4 Intended status: Informational Cisco Systems, Inc. 5 Expires: April 25, 2019 L. Bertz 6 Sprint 7 A. Akhavain 8 Huawei Canada Research Centre 9 S. Matsushima 10 SoftBank 11 D. Voyer 12 Bell Canada 13 October 22, 2018 15 Segment Routing IPv6 for mobile user-plane PoCs 16 draft-camarillo-dmm-srv6-mobile-pocs-01 18 Abstract 20 This document describes the ongoing proof of concepts of 21 [I-D.ietf-dmm-srv6-mobile-uplane] and their progress. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at https://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on April 25, 2019. 40 Copyright Notice 42 Copyright (c) 2018 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (https://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 58 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 59 3. M-CORD C3PO . . . . . . . . . . . . . . . . . . . . . . . . . 3 60 3.1. PoC phases . . . . . . . . . . . . . . . . . . . . . . . 3 61 3.2. Activity report . . . . . . . . . . . . . . . . . . . . . 3 62 3.2.1. Phase 1 . . . . . . . . . . . . . . . . . . . . . . . 3 63 4. Open Air Interface . . . . . . . . . . . . . . . . . . . . . 4 64 4.1. PoC phases . . . . . . . . . . . . . . . . . . . . . . . 4 65 4.1.1. Phase 1: Mobile Core Migration from IPv4-GTP to SRv6 5 66 4.2. Activity report . . . . . . . . . . . . . . . . . . . . . 6 67 5. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 6 68 6. Informative References . . . . . . . . . . . . . . . . . . . 7 69 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 71 1. Introduction 73 The [I-D.ietf-dmm-srv6-mobile-uplane] proposes SRv6 as userplane 74 protocol for mobile networks. As part of this work we have decided 75 to create a series of PoCs with the objective to prove the viability 76 and feasibility of such proposal. 78 For this reason we have two ongoing PoCs using M-CORD C3PO and OAI, 79 that are progressing towards a full implementation of the mechanisms 80 described in such I-D. 82 This I-D contains a formal definition of the PoCs and will summarize 83 it's findings. Anyone interested in participating in the ongoing 84 PoCs or propose new ones is welcome to join us. 86 2. Terminology 88 This document adopts the terminology of 89 [I-D.ietf-dmm-srv6-mobile-uplane]. 91 This document uses the terms N3, N6 and N9 interfaces, as well as UPF 92 and gNB as refered to in [TS.23501]. 94 3. M-CORD C3PO 96 M-CORD is an open-source 97 project from ONF focused on building a cloud-native virtualized and 98 dissagregated RAN and EPC. 100 As part of the M-CORD project, the C3PO component is part of the NGIC 101 (Next Generation Infrastructure Core) 102 . 104 The scope of this PoC is to extend the C3PO component to support 105 natively SRv6 on the N6 and N9 interfaces and have SRv6-supported 106 UPFs. 108 3.1. PoC phases 110 This PoC is divided in several phases: 112 1. SRv6 in transport network with no impact to EPC 113 2. SRv6 native in N6 interface (GiLAN) with SRv6 transport network 114 3. SRv6 native in N6 and N9 interfaces with N3 interworking 115 mechanisms 117 3.2. Activity report 119 Phase 1 has been completed. Ongoing development of phase 2. 121 3.2.1. Phase 1 123 We used FD.io VPP to simulate an SRv6 124 transport network with three SRv6 routers in the N9 interface 125 simulating a transport network. 127 As part of this transport network, we run two simulations: 129 In the first simulation we steered the IPv4/GTP traffic into an SR 130 policy that encapsulated the packet with an SRv6 header containing 131 two SIDs. 133 In the second simulation we steered the IPv4/GTP traffic into an SR 134 policy that removed the IPv4/GTP headers and placed the GTP header 135 information (i.e. TEID) into an SRv6 SID. The last SID of the SR 136 policy corresponds to an End.M.GTP4.E function, that decapsulates 137 SRv6 traffic restoring the IPv4/GTP header. The objective of the 138 second simulation is to show the IPv4/GTP interworking mechanism via 139 an uplink classifier behaving as SR-GW, as defined in Section 6.4 of 140 [I-D.ietf-dmm-srv6-mobile-uplane] . 142 After Phase 1, we concluded that SRv6 as mobility transport network 143 works fine, with an expected MTU overhead due to the original PDU 144 encapsulation. The IPv4/GTP interworking mechanism in the scope of 145 phase 1 is also fully functional. This mechanism will be further 146 tested as the POC progresses and a native SRv6-based UPF is 147 developed. 149 4. Open Air Interface 151 Open Air Interface (OAI) is an open-source software 152 that implements the 153 3GPP stack. OAI is composed of two major projects: OAI-RAN and OAI- 154 CN. 156 o OAI-RAN implements the 4G LTE and 5G Radio Access Network. Both 157 the gNB as well as the UE are implemented. 158 o OAI-Core Network implements the 4G LTE Evolved Packet Core (EPC) 159 and 5G Core Network. 161 The scope of this PoC is to extend the OAI-RAN and OAI-CN components 162 to support natively SRv6 on the N3 and N9 interfaces, and have 163 SRv6-supported gNBs and UPFs. 165 4.1. PoC phases 167 The primary goal of this POC is to show SRv6 as a data plane 168 replacement for GTP on both N3 and N9 interfaces. The POC also aims 169 to demonstrate a smooth migration path during deployment and 170 transition period from IPv4-GTP and IPv6-GTP to an end to end SRv6 171 data plane. 173 The PoC functions within the existing OAI model. OAI currently 174 doesn't provide support for S5/S8 interface. The implementation 175 instead provides an integrated SGW and PGW S/PGW module and therefore 176 there is no GTP tunnel between these two entities. This limitation 177 has an impact on the POC strategy and its implementation phases. 179 This PoC is divided into several phases: 181 1.- N3 via SRv6 GW VNFs and no impact on 3GPP control plane. 183 1.1.- Mobile Core Migration from IPv4-GTP to SRv6 184 1.2.- Mixed IPv4-GTP/IPv6-GTP Mobile Core Over SRv6 186 2.- N3 via SRv6 eNB and S/PGW integrated modules and no impact on 187 3GPP control plane. 189 2.1.- Mobile Core Migration from IPv4-GTP to SRv6 190 2.2.- Mixed IPv4-GTP/IPv6-GTP Mobile Core Over SRv6 192 3.- N3 via SRv6 support of ID-LOC architecture 194 Important notes: 196 - The above phases and solution strategy can easily be extended to 197 the N9 interface. However, although the N9 interface is well 198 within the scope of this PoC, the effort required to changes the 199 OAI code base to support S5/S8 and separate SGW and PGW modules 200 will push the project well beyond the timeline of this PoC and as 201 such are not currently part of the PoC. 202 - Support for service programming, TE, QoS, entropy, and other 203 enhanced features are also within the scope of this PoC, but will 204 also fall beyond the time line of this project and are not 205 currently considered in this PoC. 206 - The above items can be pulled back into the project based on demand 207 and assistance from others. 209 4.1.1. Phase 1: Mobile Core Migration from IPv4-GTP to SRv6 211 Phase one of this POC focuses on demonstrating a smooth migration 212 path from the existing mobile core networks with IPv4 GTP based user 213 plane to SRv6 user plane with absolutely no impact on 3GPP control 214 plane. The idea is to employ SRv6 gateways between mobile core 215 equipment such as eNB, SGW, and PGW, intercept GTP traffic, and carry 216 UE's payload through SRv6 newtwork by encoding GTP information into 217 the SIDs. 219 In this POC as it was mentioned earlier we use OAI open source 220 software. OAI implements gNB as an stand alone entitiy, but bundles 221 MME, SGW and PGW into a single package. We employ three Linux PCs in 222 oursetup. Two of these machines run the gNB and one of the SRv6 GWs. 223 The thrid machines employs virtualisation and instantiates two 224 virtual machines. The second SRv6 gateway runs in one of the virtual 225 machine while the other virtual machines executes the code for the 226 combinged MME, SGW, PGW. The code in SRv6 gateways is based on VPP 227 implementation in Linux Foundation. We modified this code to 228 intercept GTP packets, extract GTP information, and encode GTP 229 information into the SIDs. Given that today's mobile core don't deal 230 with multiple UPFs, the resulting SRv6 haeader doesn't require any 231 SRH to carry GTP information across the network. Therefore, in this 232 phase, the resulting SRv6 packets are simply IPv6 packets with their 233 DA set to SIDs. The following diagratm shows the POC configuration. 235 +--------------------------+ 236 | +========+| 237 +--+ \|/ | | +---+ || 238 |UE| | | | |HSS| || 239 +--+ | | | +-+-+ || 240 +--+ | | | || 241 | | | +-+-+ || 242 +-+ | | |MME| || 243 | | | +---+ || 244 | GTP<->SID | GTP<->SID | || 245 +---+---+ +-----+ +--------+ | +========+ |+------+|| 246 | USRP | | | | | | | | || ||| 247 |(Ettus +---+ gNB +-GTP--+ SRGW-1 +--SRv6-|-+ SRGW-2 +-GTP-|+ SPGW ||| 248 | B210) | ^ | | | | | | | || ||| 249 +-------+ | +-----+ +--------+ | +========+ |+--+---+|| 250 | | VM-1 | | || 251 USB | | | || 252 | +========+| 253 | VM-2 | | 254 | | | 255 +--------------------|-----+ 256 | 257 | 258 DN 260 POC Configuration 262 In this implementation, the SRGW at one end extracts relavant GTP 263 informaton(SA, DA, TEID) from GTP and encodes them into the lower 96 264 bits of SID. The SID is then copied into the DA of IPv6 header and 265 the packet is forwarded toward the SRGW at the far end. Receiving 266 the SRv6 packet, the far end SRGW recognises the SID as local and 267 executes a set of functions that extracts GTP information from the 268 SID, forms the GTP packet by adding relevant UDP and GTP headers and 269 forward this reconstructed GTP packet to its associated mobile core 270 node. 272 4.2. Activity report 274 Development started. Phase 1 has been completed. 276 5. Contributors 278 Chenchen Liu 279 Huawei Technolgies Co., Ltd. 280 Shenzhen, China 281 Email: liuchenchen1@huawei.com 283 Arun Rajagopal 284 Sprint 285 United States of America 287 Email: Arun.Rajagopal@sprint.com 289 Mark Bales 290 Sprint 291 United States of America 293 Email: Mark.Bales@sprint.com 295 Robert Butler 296 Sprint 297 United States of America 299 Email: Robert.Butler@sprint.com 301 6. Informative References 303 [I-D.filsfils-spring-srv6-network-programming] 304 Filsfils, C., Camarillo, P., Leddy, J., 305 daniel.voyer@bell.ca, d., Matsushima, S., and Z. Li, "SRv6 306 Network Programming", draft-filsfils-spring-srv6-network- 307 programming-05 (work in progress), July 2018. 309 [I-D.ietf-dmm-srv6-mobile-uplane] 310 Matsushima, S., Filsfils, C., Kohno, M., Camarillo, P., 311 daniel.voyer@bell.ca, d., and C. Perkins, "Segment Routing 312 IPv6 for Mobile User Plane", draft-ietf-dmm-srv6-mobile- 313 uplane-02 (work in progress), July 2018. 315 [TS.23501] 316 3GPP, "System Architecture for the 5G System", 3GPP TS 317 23.501 15.0.0, November 2017. 319 Authors' Addresses 321 Pablo Camarillo Garvia 322 Cisco Systems, Inc. 323 Spain 325 Email: pcamaril@cisco.com 326 Clarence Filsfils 327 Cisco Systems, Inc. 328 Belgium 330 Email: cf@cisco.com 332 Lyle T Bertz 333 Sprint 334 United States of America 336 Email: Lyle.T.Bertz@sprint.com 338 Arashmid Akhavain 339 Huawei Canada Research Centre 340 Canada 342 Email: arashmid.akhavain@huawei.com 344 Satoru Matsushima 345 SoftBank 346 Tokyo 347 Japan 349 Email: satoru.matsushima@g.softbank.co.jp 351 Daniel Voyer 352 Bell Canada 353 Canada 355 Email: daniel.voyer@bell.ca