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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group D. Farinacci 3 Internet-Draft lispers.net 4 Intended status: Experimental P. Pillay-Esnault 5 Expires: September 19, 2018 U. Chunduri 6 Huawei Technologies 7 March 18, 2018 9 LISP for the Mobile Network 10 draft-farinacci-lisp-mobile-network-03 12 Abstract 14 This specification describes how the LISP architecture and protocols 15 can be used in a LTE/5G mobile network to support session survivable 16 EID mobility. A recommendation is provided to SDOs on how to 17 integrate LISP into the mobile network. 19 Status of This Memo 21 This Internet-Draft is submitted in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF). Note that other groups may also distribute 26 working documents as Internet-Drafts. The list of current Internet- 27 Drafts is at https://datatracker.ietf.org/drafts/current/. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 This Internet-Draft will expire on September 19, 2018. 36 Copyright Notice 38 Copyright (c) 2018 IETF Trust and the persons identified as the 39 document authors. All rights reserved. 41 This document is subject to BCP 78 and the IETF Trust's Legal 42 Provisions Relating to IETF Documents 43 (https://trustee.ietf.org/license-info) in effect on the date of 44 publication of this document. Please review these documents 45 carefully, as they describe your rights and restrictions with respect 46 to this document. Code Components extracted from this document must 47 include Simplified BSD License text as described in Section 4.e of 48 the Trust Legal Provisions and are provided without warranty as 49 described in the Simplified BSD License. 51 Table of Contents 53 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 54 2. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 4 55 3. Design Overview . . . . . . . . . . . . . . . . . . . . . . . 6 56 4. Addressing and Routing . . . . . . . . . . . . . . . . . . . 13 57 5. gNB/eNodeB LISP Functionality . . . . . . . . . . . . . . . . 13 58 6. UPF/pGW LISP Functionality . . . . . . . . . . . . . . . . . 14 59 7. Compatible Data-Plane using GTP . . . . . . . . . . . . . . . 14 60 8. Roaming and Packet Loss . . . . . . . . . . . . . . . . . . . 15 61 9. Mobile Network LISP Mapping System . . . . . . . . . . . . . 15 62 10. LISP Over the 5G N3/N6/N9 Interfaces . . . . . . . . . . . . 15 63 11. Multicast Considerations . . . . . . . . . . . . . . . . . . 17 64 12. Security Considerations . . . . . . . . . . . . . . . . . . . 18 65 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 66 14. SDO Recommendations . . . . . . . . . . . . . . . . . . . . . 18 67 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 68 15.1. Normative References . . . . . . . . . . . . . . . . . . 18 69 15.2. Informative References . . . . . . . . . . . . . . . . . 19 70 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 22 71 Appendix B. Document Change Log . . . . . . . . . . . . . . . . 23 72 B.1. Changes to draft-farinacci-lisp-mobile-network-03.txt . . 23 73 B.2. Changes to draft-farinacci-lisp-mobile-network-02.txt . . 23 74 B.3. Changes to draft-farinacci-lisp-mobile-network-01.txt . . 23 75 B.4. Changes to draft-farinacci-lisp-mobile-network-00.txt . . 23 76 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23 78 1. Introduction 80 The LISP architecture and protocols [RFC6830] introduces two new 81 numbering spaces, Endpoint Identifiers (EIDs) and Routing Locators 82 (RLOCs) which provide an architecture to build overlays on top of the 83 underlying Internet. Mapping EIDs to RLOC-sets is accomplished with 84 a Mapping Database System. By using a level of indirection for 85 routing and addressing, separating an address identifier from its 86 location can allow flexible and scalable mobility. By assigning EIDs 87 to mobile devices and RLOCs to the network nodes that support such 88 mobile devices, LISP can provide seamless mobility. 90 For a reading audience unfamiliar with LISP, a brief tutorial level 91 document is available at [I-D.ietf-lisp-introduction]. 93 This specification will describe how LISP can be used to provide 94 layer-3 mobility within and across an LTE [LTE401-3GPP] [LTE402-3GPP] 95 and 5G [ARCH5G-3GPP] [PROC5G-3GPP] mobile network. 97 The following are the design requirements: 99 1. Layer-3 address mobility is provided within a mobile network RAN 100 supported by a UPF/pGW region (intra-UPF/pGW) as well as across 101 UPF/pGW regions (inter-UPF/pGW). 103 2. UE nodes can get layer-3 address mobility when roaming off the 104 mobile network to support Fixed Mobile Convergence [FMC]. 106 3. Transport layer session survivability exists while roaming 107 within, across, and off of the mobile network. 109 4. No address management is required when UEs roam. EID addresses 110 are assigned to UEs at subscription time. EIDs can be reassigned 111 when UE ownership changes. 113 5. The design will make efficient use of radio resources thereby not 114 adding extra headers to packets that traverse the RAN. 116 6. The design can support IPv4 unicast and multicast packet delivery 117 and will support IPv6 unicast and multicast packet delivery. 119 7. The design will allow use of both the GTP [GTPv1-3GPP] 120 [GTPv2-3GPP] and LISP [I-D.ietf-lisp-rfc6830bis] data-planes 121 while using the LISP control-plane and mapping system. 123 8. The design can be used for either 4G/LTE and 5G mobile networks 124 and may be able to support interworking between the different 125 mobile networks. 127 9. The LISP architecture provides a level of indirection for routing 128 and addressing. From a mobile operator's perspective, these 129 mechanisms provide advantages and efficiencies for the URLLC, 130 FMC, and mMTC use cases. See Section 2 for definitions and 131 references of these use cases. 133 The goal of this specification is take advantage of LISP's non- 134 disruptive incremental deployment benefits. This can be achieved by 135 changing the fewest number of components in the mobile network. The 136 proposal suggests adding LISP functionality only to gNB/eNodeB and 137 UPF/pGW nodes. There are no hardware or software changes to the UE 138 devices or the RF-based RAN to realize this architecture. The LISP 139 mapping database system is deployed as an addition to the mobile 140 network and does not require any coordination with existing 141 management and provisioning systems. 143 Similar ID Oriented Networking (ION) mechanisms for the 5G 144 [ARCH5G-3GPP] [PROC5G-3GPP] mobile network are also being considered 145 in other standards organizations such as ETSI [ETSI-NGP] and ITU 146 [ITU-IMT2020]. The NGMN Alliance describes Locator/ID separation an 147 enabler to meet Key Performance Indicator Requirements [NGMN]. 149 2. Definition of Terms 151 xTR: Is a LISP node in the network that runs the LISP control-plane 152 and data-plane protocols according to [I-D.ietf-lisp-rfc6830bis] 153 and [I-D.ietf-lisp-rfc6833bis]. A formal definition of an xTR can 154 be found in [RFC6830]. In this specification, a LISP xTR is a 155 node that runs the LISP control-plane with the GTP data-plane. 157 EID: Is an Endpoint Identifier. EIDs are assigned to UEs and other 158 Internet nodes in LISP sites. A formal definition of an EID can 159 be found in [RFC6830]. 161 UE EID: A UE can be assigned an IPv4 and/or an IPv6 address either 162 statically, or dynamically as is the procedure in the mobile 163 network today. These IP addresses are known as LISP EIDs and are 164 registered to the LISP mapping system. These EIDs are used as the 165 source address in packets that the UE originates. 167 RLOC: Is an Routing Locator. RLOCs are assigned to gNB/eNodeBs and 168 UPF/pGWs and other LISP xTRs in LISP sites. A formal definition 169 of an RLOC can be found in [RFC6830]. 171 Mapping System: Is the LISP mapping database system that stores EID- 172 to-RLOC mappings. The mapping system is centralized for use and 173 distributed to scale and secure deployment. LISP Map-Register 174 messages are used to publish mappings and LISP Map-Requests 175 messages are used to lookup mappings. LISP Map-Reply messages are 176 used to return mappings. EID-records are used as lookup keys, and 177 RLOC-records are returned as a result of the lookup. Details can 178 be found in [RFC6833]. 180 LISP Control-Plane: In this specification, a LISP xTR runs the LISP 181 control-plane which originates, consumes, and processes Map- 182 Request, Map-Register, Map-Reply, and Map-Notify messages. 184 RAN: Radio Access Network where UE nodes connect to gNB/eNodeB nodes 185 via radios to get access to the Internet. 187 EPC: Evolved Packet Core [EPS-3GPP] system is the part of the mobile 188 network that allows the RAN to connect to a data packet network. 189 The EPC is a term used for the 4G/LTE mobile network. 191 NGC: Next Generation Core [EPS-3GPP] system is the part of the 5G 192 mobile network that allows the RAN to connect to a data packet 193 network. The NGC is roughly equivalent to the 4G EPC. 195 GTP: GTP [GTPv1-3GPP] [GTPv2-3GPP] is the UDP tunneling mechanism 196 used in the LTE/4G and 5G mobile network. 198 UE: User Equipment as defined by [GPRS-3GPP] which is typically a 199 mobile phone. The UE is connected to the network across the RAN 200 to gNB/eNodeB nodes. 202 eNodeB: Is the device defined by [GPRS-3GPP] which borders the RAN 203 and connects UEs to the EPC in a 4G/LTE mobile network. The 204 eNodeB nodes are termination point for a GTP tunnel and are LISP 205 xTRs. The equivalent term in the 5G mobile network is "(R)AN" and 206 "5G-NR", or simply "gNB". In this document, the two terms are 207 used interchangeably. 209 pGW: Is the PDN-Gateway as defined by [GPRS-3GPP] connects the EPC 210 in a 4G/LTE mobile network to the Internet. The pGW nodes are 211 termination point for a GTP tunnel and is a LISP xTR. The 212 equivalent user/data-plane term in the 5G mobile network is the 213 "UPF", which also has the capability to chain network functions. 214 In this document, the two terms are used interchangeably to mean 215 the border point from the EPC/NGC to the Internet. 217 URLLC: Ultra-Reliable and Low-Latency provided by the 5G mobile 218 network for the shortest path between UEs [NGMN]. 220 FMC: Fixed Mobile Convergence [FMC] is a term used that allows a UE 221 device to move to and from the mobile network. By assigning a 222 fixed EID to a UE device, LISP supports transport layer continuity 223 between the mobile network and a fixed infrastructure such as a 224 WiFi network. 226 mMTC: Massive Machine-Type Services [mMTC] is a term used to refer 227 to using the mobile network for large-scale deployment of Internet 228 of Things (IoT) applications. 230 3. Design Overview 232 LISP will provide layer-3 address mobility based on the procedures in 233 [I-D.ietf-lisp-eid-mobility] where the EID and RLOCs are not co- 234 located. In this design, the EID is assigned to the UE device and 235 the RLOC(s) are assigned to gNB/eNodeB nodes. So any packets going 236 to a UE are always encapsulated to the gNB/eNodeB that associates 237 with the UE. For data flow from the UE to any EIDs (or destinations 238 to non-LISP sites) that are outside of the NGC/EPC, use the RLOCs of 239 the UPF/pGW nodes so the UPF/pGW can send packets into the Internet 240 core (unencapsulated). 242 The following procedures are used to incorporate LISP in the NGC/EPC: 244 o UEs are assigned EIDs. They usually never change. They identify 245 the mobile device and are used for transport connections. If 246 privacy for EIDs is desired, refer to details in 247 [I-D.ietf-lisp-eid-anonymity]. 249 o gNB/eNodeB nodes are LISP xTRs. They have GTP, and optionally 250 LISP, tunnels to the UPF/pGW nodes. The gNB/eNodeB is the RLOC 251 for all EIDs assigned to UE devices that are attached to the gNB/ 252 eNodeB. 254 o UPF/pGW nodes are LISP xTRs. They have GTP, and optionally LISP, 255 tunnels to the gNB/eNodeB nodes. The UPF/pGW is the RLOC for all 256 traffic destined for the Internet. 258 o The LISP mapping system runs in the NGC/EPC. It maps EIDs to 259 RLOC-sets. 261 o Traffic from a UE to UE within a UPF/pGW region can be 262 encapsulated from gNB/eNodeB to another gNB/eNodeB or via the UPF/ 263 pGW, acting as an RTR [RFC6830], to provide data-plane policy. 265 o Traffic from a UE to UE across a UPF/pGW region have these options 266 for data flow: 268 1. Encapsulation by a gNB/eNodeB in one region to a gNB/eNodeB in 269 another region. 271 2. Encapsulation by a gNB/eNodeB in one region to a UPF/pGW in 272 the same region and then the UPF/pGW reencapsulates to a gNB/ 273 eNodeB in another region. 275 3. Encapsulation by a gNB/eNodeB in one region to a UPF/pGW in 276 another region and then the UPF/pGW reencapsulates to a gNB/ 277 eNodeB in its same region 279 4. Encapsulation by the gNB/eNodeB to a LISP xTR outside of the 280 mobile network. An xTR outside of the mobile network could be 281 a router in a data-center, a router at the edge of a WAN at a 282 remote branch, or a WiFi access-point, and even a gNB/eNodeB 283 in another carrier's mobile network. All these deployment 284 options are to be considered for future architectures. 286 o Note when encapsulation happens between a gNB/eNodeB and a UPF/ 287 pGW, GTP is used as the data-plane and when encapsulation between 288 two gNB/eNodeBs occur, LISP can be used as the data-plane when 289 there is no X2 interface [X2-3GPP] between the gNB/eNodeB nodes. 291 o The UPF/pGW nodes register their RLOCs for a default EID-prefix to 292 the LISP mapping system. This is done so gNB/eNodeB nodes can 293 find UPF/pGW nodes to encapsulate to. 295 o The gNB/eNodeB nodes register EIDs to the mapping system for the 296 UE nodes. The registration occurs when gNB/eNodeB nodes discover 297 the layer-3 addresses of the UEs that connect to them. The gNB/ 298 eNodeB nodes register multiple RLOCs associated with the EIDs to 299 get multi-homing and path diversity benefits from the NGC/EPC 300 network. 302 o When a UE moves off a gNB/eNodeB, the gNB/eNodeB node deregisters 303 itself as an RLOC for the EID associated with the UE. 305 o Optionally, and for further study for future architectures, the 306 gNB/eNodeB or UPF/pGW could encapsulate to an xTR that is outside 307 of the NGC/EPC network. They could encapsulate to a LISP CPE 308 router at a branch office, a LISP top-of-rack router in a data 309 center, a LISP wifi access-point, LISP border routers at a hub 310 site, and even a LISP router running in a VM or container on a 311 server. 313 The following diagram illustrates the LTE mobile network topology and 314 structure [LTE401-3GPP] [LTE402-3GPP]: 316 (--------------------------------------------) 317 ( ) 318 ( Internet ) 319 ( ) 320 (--------------------------------------------) 321 | | 322 | | 323 (---------|---------) (---------|---------) 324 ( UPF-pGW ) ( UPF-pGW ) 325 ( ) ( ) 326 ( NGC/EPC ) ( NGC/EPC ) 327 ( ) ( ) 328 ( gNB-eNB gNB-eNB ) ( gNB-eNB gNB-eNB ) 329 (---/--\-----/--\---) (---/--\-----/--\---) 330 / \ / \ / \ / \ 331 / \ / \ / \ / \ 332 / \ / \ 333 / RAN \ / RAN \ 334 / \ / \ 335 ( UE UE UE ) ( UE UE UE ) 337 LTE/5G Mobile Network Architecture 339 The following diagram illustrates how LISP is used on the mobile 340 network: 342 (1) IPv6 EIDs are assigned to UEs. 343 (2) RLOCs assigned to gNB/eNodeB nodes are [a1,a2], [b1,b2], [c1,c2], [d1,d2] 344 on their uplink interfaces. 345 (3) RLOCs assigned to UPF/pGW nodes are [p1,p2], [p3,p4]. 346 (4) RLOCs can be IPv4 or IPv6 addresses or mixed RLOC-sets. 348 (--------------------------------------------) 349 ( ) 350 ( Internet ) 351 ( ) 352 (--------------------------------------------) 353 | | 354 | | 355 (---------|---------) (---------|---------) 356 ( UPF-pGW ) ( UPF-pGW ) 357 ( p1 p2 ) ( p3 p4 ) 358 ( ) ( ) 359 ( NGC/EPC ) ( NGC/EPC ) 360 ( ) ( ) 361 ( a1 a2 b1 b2 ) ( c1 c2 d1 d2 ) 362 ( gNB-eNB gNB-eNB ) ( gNB-eNB gNB-eNB ) 363 (---/--\-----/--\---) (---/--\-----/--\---) 364 / \ / \ / \ / \ 365 / \ / \ / \ / \ 366 / \ / \ 367 / RAN \ / RAN \ 368 / \ / \ 369 ( UE UE UE ) ( UE UE UE ) 370 EIDs: a::1 b::1 c::1 x::1 y::1 z::1 372 Mobile Network with EID/RLOC Assignment 374 The following table lists the EID-to-RLOC entries that reside in the LISP 375 Mapping System when the above UEs are are attached to the 4 gNB/eNodeBs: 377 EID-Record RLOC-Record Commentary Footnote 378 0::/0 [p1,p2,p3 p4] gNB/eNodeBs encap to p1-p4 for Internet (1) 379 destinations which are non-EIDs 381 a::1/128 [a1,a2] UPF/pGWs load-split traffic to [a1,a2] for (2) 382 UE a::1 and it can move to [b1,b2] 384 b::1/128 [a1,a2] gNB/eNodeB tracks both UEs a::1 and b::1, (3) 385 it can do local routing between the UEs 387 c::1/128 [b1,b2] UE c::1 can roam to [c1,c2] or [d1,d2], (4) 388 may use UPF/pGW [p1,p2] after move 390 x::1/128 [c1,c2] UE x::1 can talk directly to UE y::1, (5) 391 gNB/eNodeBs encap to each other 393 y::1/128 [d1,d2] UE can talk to Internet when [d1,d2], (6) 394 encap to UPF/pGW [p3,p4] or use backup [p1,p2] 396 z::1/128 [d1,d2] UE z::1 can talk to a::1 directly (7) 397 where [d1,d2] encaps to [a1,a2] 399 (1) For packets that flow from UE nodes to destinations that are not 400 in LISP sites, the gNB/eNodeB node use one of the RLOCs p1, p2, p3, 401 or p4 as the destination address in the outer encapsulated header. 402 Encapsulated packets are then routed by the NGC/EPC core to the UPF/ 403 pGW nodes. In turn, the UPF/pGW nodes, then route packets into the 404 Internet core. 406 (2) Packets that arrive to UPF/pGW nodes from the Internet destined 407 to UE nodes are encapsulated to one of the gNB/eNodeB RLOCs a1, a2, 408 b1, b2. When UE, with EID a::1 is attached to the leftmost gNB/ 409 eNodeB, the EID a::1 is registered to the mapping system with RLOCs 410 a1 and a2. When UE with EID c::1 is attached to the rightmost gNB/ 411 eNodeB (in the left region), the EID c::1 is registered to the 412 mapping system with RLOCs b1 and b2. 414 (3) If UE with EID a::1 and UE with EID b::1 are attached to the same 415 gNB/eNodeB node, the gNB/eNodeB node tracks what radio interface to 416 use to route packets from one UE to the other. 418 (4) If UE with EID c::1 roams away from gNB/eNodeB with RLOCs b1 and 419 b2, to the gNB/eNodeB with RLOCs c1 and c2 (in the rightmost region), 420 packets destined toward the Internet, can use any UPF/pGW. Any 421 packets that flow back from the Internet can use any UPF/pGW. In 422 either case, the UPF/pGW is informed by the mapping system that the 423 UE with EID c::1 has new RLOCs and should now encapsulate to either 424 RLOC c1 or c2. 426 (5) When UE with EID x::1 is attached to gNB/eNodeB with RLOCs c1 and 427 c2 and UE with EID y::1 is attached to gNB/eNodeB with RLOCs d1 and 428 d2, they can talk directly, on the shortest path to each gNB/eNodeB, 429 when each encapsulate packets to each other's RLOCs. 431 (6) When packets from UE with EID y::1 are destined for the Internet, 432 the gNB/eNodeB with RLOCs d1 and d2 that the UE is attached to can 433 use any exit UPF/pGWs RLOCs p1, p2, p3, or p4. 435 (7) UE with EID z::1 can talk directory to UE with EID a::1 by each 436 gNB/eNodeB they are attached to encapsulsates to each other's RLOCs. 437 In case (5), the two gNB/eNodeB's were in the same region. In this 438 case, the gNB/eNodeBs are in different regions. 440 The following abbreviated diagram shows a topology that illustrates 441 how a UE roams with LISP across UPF/pGW regions: 443 (--------------------------------------------) 444 ( ) 445 ( Internet ) 446 ( ) 447 (--------------------------------------------) 448 | | 449 | | 450 (---------|---------) (---------|---------) 451 ( UPF-pGW ) ( UPF-pGW ) 452 ( p1 p2 ) ( p3 p4 ) 453 ( ) ( ) 454 ( NGC/EPC ) ( NGC/EPC ) 455 ( ) ( ) 456 ( a1 a2 b1 b2 ) ( c1 c2 d1 d2 ) 457 ( gNB-eNB gNB-eNB ) ( gNB-eNB gNB-eNB ) 458 (---/--\-----/--\---) (---/--\-----/--\---) 459 / \ / \ / \ / \ 460 / \ / \ / \ / \ 461 / \ / \ 462 / RAN \ / RAN \ 463 / \ / \ 464 ( UE ------------------------------> UE ) 465 a::1 a::1 467 UE EID Mobility 469 The contents of the LISP mapping database before UE moves: 471 EID-Record RLOC-Record Commentary 472 0::/0 [p1,p2,p3,p4] gNB/eNodeB [a1,a2] encaps to p1-p4 for Internet 473 destinations when a::1 on gNB/eNodeB [a1,a2] 475 a::1/128 [a1,a2] Before UE moves to other UPF/pGW region 477 The contents of the LISP mapping database after UE moves: 479 EID-Record RLOC-Record Commentary 480 0::/0 [p1,p2,p3,p4] gNB/eNodeB [d1,d2] encaps to p1-p4 for Internet 481 destinations when a::1 moves to gNB/eNodeB 482 [d1,d2] 484 a::1/128 [d1,d2] After UE moves to new UPF/pGW region 485 4. Addressing and Routing 487 UE based EID addresses will be IPv6 addresses. It will be determined 488 at a future time what length the IPv6 prefix will be to cover all UEs 489 in a mobile network. This coarse IPv6 prefix is called an EID-prefix 490 where more-specific EID-prefixes will be allocated out of it for each 491 UPF/pGW node. Each UPF/pGW node is responsible for advertising the 492 more-specific EID-prefix into the Internet routing system so they can 493 attract packets from non-EIDs nodes to UE EIDs. 495 An RLOC address will either be an IPv4 or IPv6 address depending on 496 the support for single or dual-stack address-family in the NGC/EPC 497 network. An RLOC-set in the mapping system can have a mixed address- 498 family locator set. There is no requirement for the NGC/EPC to 499 change to support one address-family or the other. And there is no 500 requirement for the NGC/EPC network to support IPv4 multicast or IPv6 501 multicast. The LISP overlay will support both. 503 The only requirement for RLOC addresses is that they are routable in 504 the NGC/EPC and the Internet core network. 506 The requirements of the LISP and GTP data-plane overlay is to support 507 a layer-3 overlay network only. There is no architectural 508 requirement to support layer-2 overlays. However, operators may want 509 to provide a layer-2 LAN service over their mobile network. Details 510 about how LISP supports layer-2 overlays can be found in 511 [I-D.ietf-lisp-eid-mobility]. 513 5. gNB/eNodeB LISP Functionality 515 The gNB/eNodeB node runs as a LISP xTR for control-plane 516 functionality and runs GTP for data-plane functionality. Optionally, 517 the LISP data-plane can be used to establish dynamic tunnels from one 518 gNB/eNodeB node to another gNB/eNodeB node. 520 The gNB/eNodeB LISP xTR will follow the procedures of 521 [I-D.ietf-lisp-eid-mobility] to discover UE based EIDs, track them by 522 monitoring liveness, registering them when appear, and deregistering 523 them when they move away. Since the gNB/eNodeB node is an xTR, it is 524 acting as a layer-3 router and the GTP tunnel from the gNB/eNodeB 525 node to the UPF/pGW node is realizing a layer-3 overlay. This will 526 provide scaling benefits since broadcast and link-local multicast 527 packets won't have to travel across the NGC/EPC to the UPF/pGW node. 529 A day in the life of a UE originated packet: 531 1. The UE node originates an IP packet over the RAN. 533 2. The gNB/eNodeB receives the packet, extracts the source address 534 from the packet, learns the UE based EID, stores its RAN location 535 locally and registers the EID to the mapping system. 537 3. The gNB/eNodeB extracts the destination address, looks up the 538 address in the mapping system. The lookup returns the RLOC of a 539 UPF/pGW node if the destination is not an EID or an RLOC gNB/ 540 eNodeB node if the destination is a UE based EID. 542 4. The gNB/eNodeB node encapsulates the packet to the RLOC using GTP 543 or optionally the LISP data-plane. 545 It is important to note that in [I-D.ietf-lisp-eid-mobility], EID 546 discovery occurs when a LISP xTR receives an IP or ARP/ND packet. 547 However, if there are other methods to discover the EID of a device, 548 like in UE call setup, the learning and registration referenced in 549 Paragraph 2 can happen before any packet is sent. 551 6. UPF/pGW LISP Functionality 553 The UPF/pGW node runs as a LISP xTR for control-plane functionality 554 and runs GTP for data-plane functionality. Optionally, the LISP 555 data-plane can be used to establish dynamic tunnels from one UPF/pGW 556 node to another UPF/pGW or gNB/eNodeB node. 558 The UPF/pGW LISP xTR does not follow the EID mobility procedures of 559 [I-D.ietf-lisp-eid-mobility] since it is not responsible for 560 discovering UE based EIDs. A UPF/pGW LISP xTR simply follows the 561 procedures of a PxTR in [RFC6830] and for interworking to non-EID 562 sites in [RFC6832]. 564 A day in the life of a UPF/pGW received packet: 566 1. The UPF/pGW node receives a IP packet from the Internet core. 568 2. The UPF/pGW node extracts the destination address from the packet 569 and looks it up in the LISP mapping system. The lookup returns 570 an RLOC of a gNB/eNodeB node. Optionally, the RLOC could be 571 another UPF/pGW node. 573 3. The UPF/pGW node encapsulates the packet to the RLOC using GTP or 574 optionally the LISP data-plane. 576 7. Compatible Data-Plane using GTP 578 Since GTP is a UDP based encapsulating tunnel protocol, it has the 579 same benefits as LISP encapsulation. At this time, there appears to 580 be no urgent need to not continue to use GTP for tunnels between a 581 gNB/eNodeB nodes and between a gNB/eNodeB node and a UPF/pGW node. 583 There are differences between GTP tunneling and LISP tunneling. GTP 584 tunnels are setup at call initiation time. LISP tunnels are 585 dynamically encapsulating, used on demand, and don't need setup or 586 teardown. The two tunneling mechanisms are a hard state versus soft 587 state tradeoff. 589 This specification recommends for early phases of deployment, to use 590 GTP as the data-plane so a transition for it to use the LISP control- 591 plane can be achieved more easily. At later phases, the LISP data- 592 plane may be considered so a more dynamic way of using tunnels can be 593 achieved to support URLLC. 595 This specification recommends the use of procedures from 596 [I-D.ietf-lisp-eid-mobility] and NOT the use of LISP-MN 597 [I-D.ietf-lisp-mn]. Using LISP-MN states that a LISP xTR reside on 598 the mobile UE. This is to be avoided so extra encapsulation header 599 overhead is NOT sent on the RAN. The LISP data-plane or control- 600 plane will not run on the UE. 602 8. Roaming and Packet Loss 604 Using LISP for the data-plane has some advantages in terms of 605 providing near-zero packet loss. In the current mobile network, 606 packets are queued on the gNB/eNodeB node the UE is roaming to or 607 rerouted on the gNB/eNodeB node the UE has left. In the LISP 608 architecture, packets can be sent to multiple "roamed-from" and 609 "roamed-to" nodes while the UE is moving or is off the RAN. See 610 mechanisms in [I-D.ietf-lisp-predictive-rlocs] for details. 612 9. Mobile Network LISP Mapping System 614 The LISP mapping system stores and maintains EID-to-RLOC mappings. 615 There are two mapping database transport systems that are available 616 for scale, LISP-ALT [RFC6836] and LISP-DDT [RFC8111]. The mapping 617 system will store EIDs assigned to UE nodes and the associated RLOCs 618 assigned to gNB/eNodeB nodes and UPF/pGW nodes. The RLOC addresses 619 are routable addresses by the NGC/EPC network. 621 This specification recommends the use of LISP-DDT. 623 10. LISP Over the 5G N3/N6/N9 Interfaces 625 So far in this specification we have described how LISP runs on the 626 gNB and UPF nodes in the mobile network. In the 5G architecture 627 [ARCH5G-3GPP] definition, some key components are Access and Mobility 628 Management Function (AMF) and the Session Management Function (SMF). 629 These two components provide control plane functionality to off-load 630 session anchoring by distributing state and packet flow among 631 multiple nodes in the NGC. These functions can be deployed in Branch 632 Point Uplink Classifier (BP/ULCL) in data-plane nodes. 634 Here is an illustration where a B/ULCL-UPF node would appear in the 635 mobile network: 637 (--------------------------------------------) 638 ( Internet ) 639 +-> (--------------------------------------------) 640 | | 641 N6 | 642 | (---------|---------) 643 +-> ( UPF ) <-+ 644 NGC ( [p1,p2] ) | 645 ( ) N9 646 +-> ( BP/ULCL ) | 647 | ( UPF [p3,p4] ) <-+ 648 N3 ( ) 649 | ( [a1] [a2] ) 650 +-> ( gNB gNB ) 651 (---/--\-----/--\---) 652 / \ / \ 653 / \ 654 / RAN \ 655 / \ 656 ( UE UE UE ) 657 a::1 a::2 a::3 659 The BP/ULCL-UPF node is configured as an LISP RTR and uses the 660 Traffic Engineering features of LISP specified in [I-D.ietf-lisp-te]. 661 In LISP-TE an Explicit Locator Path (ELP) can be stored in the RLOC- 662 record for any given EID thereby allowing packet flow from a UE to 663 the Internet to traverse through the BP/UCLC-UPF node. A UE 664 originated packet is encapsulated by the gNB to the BP/ULCL-UPF which 665 decapsulates and reencapsulates to the UPF at the Internet border. 666 This allows LISP to run over the 5G N3 and N9 interface with one 667 mapping entry. And if the ELP contained an xTR outside of the mobile 668 network, LISP could also run over the N6 interface. 670 The contents of the LISP mapping database: 672 EID-Record RLOC-Record Commentary 673 0::/0 [ELP{a1,p3,p1}, 4 RLOC-records, 2 with paths through the BP-UPF 674 ELP{a1,p4,p2}, and 2 directly to the border UPF from UEs 675 p1, p2] connected to gNB with RLOC a1 677 a::1/128 [a1,a2] The UPF or BP-UPF can encap directly for UE with 678 EID a::1 to either gNB with optimized latency 680 a::2/128 [ELP{p1,p3,a2}, The UPF can encap to either RLOC p3 or p4 to 681 ELP{p1,p4,a2}] forward traffic through the BP-UPF on its way 682 toward gNB with RLOC a1 684 a::3/128 [ELP{p1,p3,a2}, The UPF can encap to the BP-UPF or directly 685 a2] to gNB with RLOC a2 to reach UE with EID a::3 687 11. Multicast Considerations 689 Since the mobile network runs the LISP control-plane, and the mapping 690 system is available to support EIDs for unicast packet flow, it can 691 also support multicast packet flow. Support for multicast can be 692 provided by the LISP/GTP overlay with no changes to the NGC/EPC 693 network. 695 Multicast (S-EID,G) entries can be stored and maintained in the same 696 mapping database that is used to store UE based EIDs. Both Internet 697 connected nodes, as well as UE nodes, can source multicast packets. 698 The protocol procedures from [I-D.ietf-lisp-signal-free-multicast] 699 are followed to make multicast delivery available. Both multicast 700 packet flow and UE mobility can occur at the same time. 702 A day in the life of a 1-to-many multicast packet: 704 1. A UE node joins an (S,G) multicast flow by using IGMPv2 or 705 IGMPv3. 707 2. The gNB/eNodeB node records which UE on the RAN should get 708 packets sourced by S and destined for group G. 710 3. The gNB/eNodeB node registers the (S,G) entry to the mapping 711 system with its RLOC according to the receiver site procedures in 712 [I-D.ietf-lisp-signal-free-multicast]. The gNB/eNodeB does this 713 to show interest in joining the multicast flow. 715 4. When other UE nodes join the same (S,G), their associated gNB/ 716 eNodeB nodes will follow the procedures in steps 1 through 3. 718 5. The (S,G) entry stored in the mapping database has an RLOC-set 719 which contains a replication list of all the gNB/eNodeB RLOCs 720 that registered. 722 6. A multicast packet from source S to destination group G arrives 723 at the UPF/pGW. The UPF/pGW node looks up (S,G), gets returned 724 the replication list of all joined gNB/eNodeB nodes and 725 replicates the multicast packet by encapsulating the packet to 726 each of them. 728 7. Each gNB/eNodeB node decapsulates the packet and delivers the 729 multicast packet to one or more IGMP-joined UEs on the RAN. 731 12. Security Considerations 733 For control-plane authentication and authorization procedures, this 734 specification recommends the mechanisms in 735 [I-D.ietf-lisp-rfc6833bis], LISP-SEC [I-D.ietf-lisp-sec] AND LISP- 736 ECDSA [I-D.farinacci-lisp-ecdsa-auth]. 738 For data-plane privacy procedures, this specification recommends the 739 mechanisms in [RFC8061] When the LISP data-plane is used. otherwise, 740 the NGC/EPC must provide data-plane encryption support. 742 13. IANA Considerations 744 There are no specific requests for IANA. 746 14. SDO Recommendations 748 The authors request other Standards Development Organizations to 749 consider LISP as a technology for device mobility. It is recommended 750 to start with this specification as a basis for design and develop 751 more deployment details in the appropriate Standards Organizations. 752 The authors are willing to facilitate this activity. 754 15. References 756 15.1. Normative References 758 [RFC1700] Reynolds, J. and J. Postel, "Assigned Numbers", RFC 1700, 759 DOI 10.17487/RFC1700, October 1994, 760 . 762 [RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The 763 Locator/ID Separation Protocol (LISP)", RFC 6830, 764 DOI 10.17487/RFC6830, January 2013, 765 . 767 [RFC6832] Lewis, D., Meyer, D., Farinacci, D., and V. Fuller, 768 "Interworking between Locator/ID Separation Protocol 769 (LISP) and Non-LISP Sites", RFC 6832, 770 DOI 10.17487/RFC6832, January 2013, 771 . 773 [RFC6833] Fuller, V. and D. Farinacci, "Locator/ID Separation 774 Protocol (LISP) Map-Server Interface", RFC 6833, 775 DOI 10.17487/RFC6833, January 2013, 776 . 778 [RFC6836] Fuller, V., Farinacci, D., Meyer, D., and D. Lewis, 779 "Locator/ID Separation Protocol Alternative Logical 780 Topology (LISP+ALT)", RFC 6836, DOI 10.17487/RFC6836, 781 January 2013, . 783 [RFC8060] Farinacci, D., Meyer, D., and J. Snijders, "LISP Canonical 784 Address Format (LCAF)", RFC 8060, DOI 10.17487/RFC8060, 785 February 2017, . 787 [RFC8061] Farinacci, D. and B. Weis, "Locator/ID Separation Protocol 788 (LISP) Data-Plane Confidentiality", RFC 8061, 789 DOI 10.17487/RFC8061, February 2017, 790 . 792 [RFC8111] Fuller, V., Lewis, D., Ermagan, V., Jain, A., and A. 793 Smirnov, "Locator/ID Separation Protocol Delegated 794 Database Tree (LISP-DDT)", RFC 8111, DOI 10.17487/RFC8111, 795 May 2017, . 797 15.2. Informative References 799 [ARCH5G-3GPP] 800 3GPP, "System Architecture for the 5G System", TS.23.501 801 https://portal.3gpp.org/desktopmodules/Specifications/ 802 SpecificationDetails.aspx?specificationId=3144, December 803 2016. 805 [EPS-3GPP] 806 3GPP, "Non-Access-Stratum (NAS) Protocol for Evolved 807 Packet System (EPS); Stage 3", TS.23.501 808 https://portal.3gpp.org/desktopmodules/specifications/ 809 specificationdetails.aspx?specificationid=1072, December 810 2017. 812 [ETSI-NGP] 813 ETSI-NGP, "NGP Evolved Architecture for mobility using 814 Identity Oriented Networks", NGP-004, version 0.0.3 815 https://portal.etsi.org/webapp/WorkProgram/ 816 Report_WorkItem.asp?WKI_ID=50531, May 2017. 818 [FMC] ipv6.com, "FIXED MOBILE CONVERGENCE", 819 https://www.ipv6.com/mobile/fixed-mobile-convergence/, 820 November 2006. 822 [GPRS-3GPP] 823 3GPP, "General Packet Radio Service (GPRS) for Evolved 824 Universal Terrestrial Radio Access Network (E-UTRAN) 825 Access", TS23.401 Release 8 826 https://portal.3gpp.org/desktopmodules/specifications/ 827 specificationdetails.aspx?specificationid=849, January 828 2015. 830 [GTPv1-3GPP] 831 3GPP, "General Packet Radio System (GPRS) Tunnelling 832 Protocol User Plane (GTPv1-U)", TS.29.281 833 https://portal.3gpp.org/desktopmodules/Specifications/ 834 SpecificationDetails.aspx?specificationId=1699, January 835 2015. 837 [GTPv2-3GPP] 838 3GPP, "3GPP Evolved Packet System (EPS); Evolved General 839 Packet Radio Service (GPRS) Tunnelling Protocol for 840 Control plane (GTPv2-C); Stage 3", TS.29.274 841 https://portal.3gpp.org/desktopmodules/Specifications/ 842 SpecificationDetails.aspx?specificationId=1692, January 843 2015. 845 [I-D.farinacci-lisp-ecdsa-auth] 846 Farinacci, D. and E. Nordmark, "LISP Control-Plane ECDSA 847 Authentication and Authorization", draft-farinacci-lisp- 848 ecdsa-auth-01 (work in progress), October 2017. 850 [I-D.ietf-lisp-eid-anonymity] 851 Farinacci, D., Pillay-Esnault, P., and W. Haddad, "LISP 852 EID Anonymity", draft-ietf-lisp-eid-anonymity-01 (work in 853 progress), October 2017. 855 [I-D.ietf-lisp-eid-mobility] 856 Portoles-Comeras, M., Ashtaputre, V., Moreno, V., Maino, 857 F., and D. Farinacci, "LISP L2/L3 EID Mobility Using a 858 Unified Control Plane", draft-ietf-lisp-eid-mobility-01 859 (work in progress), November 2017. 861 [I-D.ietf-lisp-introduction] 862 Cabellos-Aparicio, A. and D. Saucez, "An Architectural 863 Introduction to the Locator/ID Separation Protocol 864 (LISP)", draft-ietf-lisp-introduction-13 (work in 865 progress), April 2015. 867 [I-D.ietf-lisp-mn] 868 Farinacci, D., Lewis, D., Meyer, D., and C. White, "LISP 869 Mobile Node", draft-ietf-lisp-mn-01 (work in progress), 870 October 2017. 872 [I-D.ietf-lisp-predictive-rlocs] 873 Farinacci, D. and P. Pillay-Esnault, "LISP Predictive 874 RLOCs", draft-ietf-lisp-predictive-rlocs-01 (work in 875 progress), November 2017. 877 [I-D.ietf-lisp-rfc6830bis] 878 Farinacci, D., Fuller, V., Meyer, D., Lewis, D., and A. 879 Cabellos-Aparicio, "The Locator/ID Separation Protocol 880 (LISP)", draft-ietf-lisp-rfc6830bis-11 (work in progress), 881 March 2018. 883 [I-D.ietf-lisp-rfc6833bis] 884 Fuller, V., Farinacci, D., and A. Cabellos-Aparicio, 885 "Locator/ID Separation Protocol (LISP) Control-Plane", 886 draft-ietf-lisp-rfc6833bis-08 (work in progress), March 887 2018. 889 [I-D.ietf-lisp-sec] 890 Maino, F., Ermagan, V., Cabellos-Aparicio, A., and D. 891 Saucez, "LISP-Security (LISP-SEC)", draft-ietf-lisp-sec-14 892 (work in progress), October 2017. 894 [I-D.ietf-lisp-signal-free-multicast] 895 Moreno, V. and D. Farinacci, "Signal-Free LISP Multicast", 896 draft-ietf-lisp-signal-free-multicast-09 (work in 897 progress), March 2018. 899 [I-D.ietf-lisp-te] 900 Farinacci, D., Kowal, M., and P. Lahiri, "LISP Traffic 901 Engineering Use-Cases", draft-ietf-lisp-te-01 (work in 902 progress), October 2017. 904 [ITU-IMT2020] 905 ITU-FG, "Focus Group on IMT-2020", 906 https://www.itu.int/dms_pubrec/itu-r/rec/m/R-REC- 907 M.687-2-199702-I!!PDF-E.pdf. 909 [LTE401-3GPP] 910 3GPP, "General Packet Radio Service (GPRS) enhancements 911 for Evolved Universal Terrestrial Radio Access Network 912 (E-UTRAN) access", TS.23.401 913 https://portal.3gpp.org/desktopmodules/Specifications/ 914 SpecificationDetails.aspx?specificationId=849, January 915 2015. 917 [LTE402-3GPP] 918 3GPP, "Architecture enhancements for non-3GPP accesses", 919 TS.23.402 920 https://portal.3gpp.org/desktopmodules/Specifications/ 921 SpecificationDetails.aspx?specificationId=850, January 922 2015. 924 [mMTC] NGMN Alliance, "NGMN KPIs and Deployment Scenarios for 925 Consideration for IMT2020", https://www.ngmn.org/uploads/ 926 media/151204_NGMN_KPIs_and_Deployment_Scenarios_for_Consid 927 eration_for_IMT_2020_-_LS_Annex_V1_approved.pdf, December 928 2015. 930 [NGMN] NGMN Alliance, "5G End-to-End Architecture Framework", 931 NGMN https://www.ngmn.org/uploads/ 932 media/170511_NGMN_E2EArchFramework_v0.6.5.pdf, March 2016. 934 [PROC5G-3GPP] 935 3GPP, "Procedures for the 5G System", TS.23.502 936 https://portal.3gpp.org/desktopmodules/Specifications/ 937 SpecificationDetails.aspx?specificationId=3145, December 938 2016. 940 [X2-3GPP] 3GPP, "Evolved Universal Terrestrial Radio Access Network 941 (E-UTRAN); X2 Application Protocol (X2AP)", TS.36.423 942 https://portal.3gpp.org/desktopmodules/Specifications/ 943 SpecificationDetails.aspx?specificationId=2452, June 2017. 945 Appendix A. Acknowledgments 947 The authors would like to thank Gerry Foster and Peter Ashwood Smith 948 for their expertise with 3GPP mobile networks and for their early 949 review and contributions. The authors would also like to thank Fabio 950 Maino, Malcolm Smith, and Marc Portoles for their expertise in both 951 5G and LISP as well as for their early review comments. 953 The authors would like to give a special thank you to Ryosuke 954 Kurebayashi from NTT Docomo and Kalyani Bogineni from Verizon for 955 their operational and practical commentary. 957 Appendix B. Document Change Log 959 B.1. Changes to draft-farinacci-lisp-mobile-network-03.txt 961 o Posted March 2018. 963 o Make the spec more 5G user-friendly. That is, the design has 964 always worked for either 4G or 5G but we make it more clear about 965 5G by using some basic 5G node terminlogy. 967 o Add a section how LISP can work on the N3, N6, and N9 5G spec 968 interfaces. 970 o Describe how LISP-TE can allow BP-UPF offload functionality. 972 B.2. Changes to draft-farinacci-lisp-mobile-network-02.txt 974 o Posted mid September 2017. 976 o Editorial fixes from draft -01. 978 B.3. Changes to draft-farinacci-lisp-mobile-network-01.txt 980 o Posted September 2017. 982 o Explain each EID case illustrated in the "Mobile Network with EID/ 983 RLOC Assignment" diagram. 985 o Make a reference to mMTC as a 3GPP use-case for 5G. 987 o Add to the requirements section how mobile operators believe that 988 using Locator/ID separation mechanisms provide for more efficient 989 mobile netwowks. 991 o Indicate that L2-overlays is not recommended by this specification 992 as the LISP mobile network architeture but how operators may want 993 to deploy a layer-2 overlay service. 995 B.4. Changes to draft-farinacci-lisp-mobile-network-00.txt 997 o Initial draft posted August 2017. 999 Authors' Addresses 1000 Dino Farinacci 1001 lispers.net 1002 San Jose, CA 1003 USA 1005 Email: farinacci@gmail.com 1007 Padma Pillay-Esnault 1008 Huawei Technologies 1009 Santa Clara, CA 1010 USA 1012 Email: padma@huawei.com 1014 Uma Chunduri 1015 Huawei Technologies 1016 Santa Clara, CA 1017 USA 1019 Email: uma.chunduri@huawei.com