idnits 2.17.1 draft-ietf-lisp-rfc6830bis-26.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (November 4, 2018) is 1999 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Unused Reference: 'RFC7833' is defined on line 1754, but no explicit reference was found in the text == Outdated reference: A later version (-14) exists of draft-ietf-lisp-6834bis-02 == Outdated reference: A later version (-31) exists of draft-ietf-lisp-rfc6833bis-19 == Outdated reference: A later version (-15) exists of draft-ietf-lisp-introduction-13 == Outdated reference: A later version (-12) exists of draft-ietf-lisp-vpn-02 Summary: 0 errors (**), 0 flaws (~~), 6 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group D. Farinacci 3 Internet-Draft V. Fuller 4 Obsoletes: 6830 (if approved) D. Meyer 5 Intended status: Standards Track D. Lewis 6 Expires: May 8, 2019 Cisco Systems 7 A. Cabellos (Ed.) 8 UPC/BarcelonaTech 9 November 4, 2018 11 The Locator/ID Separation Protocol (LISP) 12 draft-ietf-lisp-rfc6830bis-26 14 Abstract 16 This document describes the Data-Plane protocol for the Locator/ID 17 Separation Protocol (LISP). LISP defines two namespaces, End-point 18 Identifiers (EIDs) that identify end-hosts and Routing Locators 19 (RLOCs) that identify network attachment points. With this, LISP 20 effectively separates control from data, and allows routers to create 21 overlay networks. LISP-capable routers exchange encapsulated packets 22 according to EID-to-RLOC mappings stored in a local Map-Cache. 24 LISP requires no change to either host protocol stacks or to underlay 25 routers and offers Traffic Engineering, multihoming and mobility, 26 among other features. 28 This document obsoletes RFC 6830. 30 Status of This Memo 32 This Internet-Draft is submitted in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF). Note that other groups may also distribute 37 working documents as Internet-Drafts. The list of current Internet- 38 Drafts is at https://datatracker.ietf.org/drafts/current/. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 This Internet-Draft will expire on May 8, 2019. 47 Copyright Notice 49 Copyright (c) 2018 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (https://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 65 1.1. Scope of Applicability . . . . . . . . . . . . . . . . . 4 66 2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 4 67 3. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 5 68 4. Basic Overview . . . . . . . . . . . . . . . . . . . . . . . 9 69 4.1. Packet Flow Sequence . . . . . . . . . . . . . . . . . . 11 70 5. LISP Encapsulation Details . . . . . . . . . . . . . . . . . 13 71 5.1. LISP IPv4-in-IPv4 Header Format . . . . . . . . . . . . . 13 72 5.2. LISP IPv6-in-IPv6 Header Format . . . . . . . . . . . . . 14 73 5.3. Tunnel Header Field Descriptions . . . . . . . . . . . . 15 74 6. LISP EID-to-RLOC Map-Cache . . . . . . . . . . . . . . . . . 20 75 7. Dealing with Large Encapsulated Packets . . . . . . . . . . . 20 76 7.1. A Stateless Solution to MTU Handling . . . . . . . . . . 21 77 7.2. A Stateful Solution to MTU Handling . . . . . . . . . . . 22 78 8. Using Virtualization and Segmentation with LISP . . . . . . . 22 79 9. Routing Locator Selection . . . . . . . . . . . . . . . . . . 23 80 10. Routing Locator Reachability . . . . . . . . . . . . . . . . 25 81 10.1. Echo Nonce Algorithm . . . . . . . . . . . . . . . . . . 26 82 11. EID Reachability within a LISP Site . . . . . . . . . . . . . 27 83 12. Routing Locator Hashing . . . . . . . . . . . . . . . . . . . 28 84 13. Changing the Contents of EID-to-RLOC Mappings . . . . . . . . 29 85 13.1. Database Map-Versioning . . . . . . . . . . . . . . . . 30 86 14. Multicast Considerations . . . . . . . . . . . . . . . . . . 31 87 15. Router Performance Considerations . . . . . . . . . . . . . . 31 88 16. Security Considerations . . . . . . . . . . . . . . . . . . . 32 89 17. Network Management Considerations . . . . . . . . . . . . . . 33 90 18. Changes since RFC 6830 . . . . . . . . . . . . . . . . . . . 33 91 19. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34 92 19.1. LISP UDP Port Numbers . . . . . . . . . . . . . . . . . 34 93 20. References . . . . . . . . . . . . . . . . . . . . . . . . . 34 94 20.1. Normative References . . . . . . . . . . . . . . . . . . 34 95 20.2. Informative References . . . . . . . . . . . . . . . . . 35 96 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 39 97 Appendix B. Document Change Log . . . . . . . . . . . . . . . . 40 98 B.1. Changes to draft-ietf-lisp-rfc6830bis-26 . . . . . . . . 40 99 B.2. Changes to draft-ietf-lisp-rfc6830bis-25 . . . . . . . . 40 100 B.3. Changes to draft-ietf-lisp-rfc6830bis-24 . . . . . . . . 40 101 B.4. Changes to draft-ietf-lisp-rfc6830bis-23 . . . . . . . . 40 102 B.5. Changes to draft-ietf-lisp-rfc6830bis-22 . . . . . . . . 40 103 B.6. Changes to draft-ietf-lisp-rfc6830bis-21 . . . . . . . . 40 104 B.7. Changes to draft-ietf-lisp-rfc6830bis-20 . . . . . . . . 41 105 B.8. Changes to draft-ietf-lisp-rfc6830bis-19 . . . . . . . . 41 106 B.9. Changes to draft-ietf-lisp-rfc6830bis-18 . . . . . . . . 41 107 B.10. Changes to draft-ietf-lisp-rfc6830bis-17 . . . . . . . . 41 108 B.11. Changes to draft-ietf-lisp-rfc6830bis-16 . . . . . . . . 41 109 B.12. Changes to draft-ietf-lisp-rfc6830bis-15 . . . . . . . . 41 110 B.13. Changes to draft-ietf-lisp-rfc6830bis-14 . . . . . . . . 42 111 B.14. Changes to draft-ietf-lisp-rfc6830bis-13 . . . . . . . . 42 112 B.15. Changes to draft-ietf-lisp-rfc6830bis-12 . . . . . . . . 42 113 B.16. Changes to draft-ietf-lisp-rfc6830bis-11 . . . . . . . . 42 114 B.17. Changes to draft-ietf-lisp-rfc6830bis-10 . . . . . . . . 42 115 B.18. Changes to draft-ietf-lisp-rfc6830bis-09 . . . . . . . . 43 116 B.19. Changes to draft-ietf-lisp-rfc6830bis-08 . . . . . . . . 43 117 B.20. Changes to draft-ietf-lisp-rfc6830bis-07 . . . . . . . . 43 118 B.21. Changes to draft-ietf-lisp-rfc6830bis-06 . . . . . . . . 43 119 B.22. Changes to draft-ietf-lisp-rfc6830bis-05 . . . . . . . . 44 120 B.23. Changes to draft-ietf-lisp-rfc6830bis-04 . . . . . . . . 44 121 B.24. Changes to draft-ietf-lisp-rfc6830bis-03 . . . . . . . . 44 122 B.25. Changes to draft-ietf-lisp-rfc6830bis-02 . . . . . . . . 44 123 B.26. Changes to draft-ietf-lisp-rfc6830bis-01 . . . . . . . . 44 124 B.27. Changes to draft-ietf-lisp-rfc6830bis-00 . . . . . . . . 45 125 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 45 127 1. Introduction 129 This document describes the Locator/Identifier Separation Protocol 130 (LISP). LISP is an encapsulation protocol built around the 131 fundamental idea of separating the topological location of a network 132 attachment point from the node's identity [CHIAPPA]. As a result 133 LISP creates two namespaces: Endpoint Identifiers (EIDs), that are 134 used to identify end-hosts (e.g., nodes or Virtual Machines) and 135 routable Routing Locators (RLOCs), used to identify network 136 attachment points. LISP then defines functions for mapping between 137 the two namespaces and for encapsulating traffic originated by 138 devices using non-routable EIDs for transport across a network 139 infrastructure that routes and forwards using RLOCs. LISP 140 encapsulation uses a dynamic form of tunneling where no static 141 provisioning is required or necessary. 143 LISP is an overlay protocol that separates control from Data-Plane, 144 this document specifies the Data-Plane, how LISP-capable routers 145 (Tunnel Routers) exchange packets by encapsulating them to the 146 appropriate location. Tunnel routers are equipped with a cache, 147 called Map-Cache, that contains EID-to-RLOC mappings. The Map-Cache 148 is populated using the LISP Control-Plane protocol 149 [I-D.ietf-lisp-rfc6833bis]. 151 LISP does not require changes to either host protocol stack or to 152 underlay routers. By separating the EID from the RLOC space, LISP 153 offers native Traffic Engineering, multihoming and mobility, among 154 other features. 156 Creation of LISP was initially motivated by discussions during the 157 IAB-sponsored Routing and Addressing Workshop held in Amsterdam in 158 October 2006 (see [RFC4984]). 160 This document specifies the LISP Data-Plane encapsulation and other 161 LISP forwarding node functionality while [I-D.ietf-lisp-rfc6833bis] 162 specifies the LISP control plane. LISP deployment guidelines can be 163 found in [RFC7215] and [RFC6835] describes considerations for network 164 operational management. Finally, [I-D.ietf-lisp-introduction] 165 describes the LISP architecture. 167 This document obsoletes RFC 6830. 169 1.1. Scope of Applicability 171 LISP was originally developed to address the Internet-wide route 172 scaling problem [RFC4984]. While there are a number of approaches of 173 interest for that problem, as LISP as been developed and refined, a 174 large number of other LISP uses have been found and are being used. 175 As such, the design and development of LISP has changed so as to 176 focus on these use cases. The common property of these uses is a 177 large set of cooperating entities seeking to communicate over the 178 public Internet or other large underlay IP infrastructures, while 179 keeping the addressing and topology of the cooperating entities 180 separate from the underlay and Internet topology, routing, and 181 addressing. 183 2. Requirements Notation 185 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 186 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 187 "OPTIONAL" in this document are to be interpreted as described in BCP 188 14 [RFC2119] [RFC8174] when, and only when, they appear in all 189 capitals, as shown here. 191 3. Definition of Terms 193 Address Family Identifier (AFI): AFI is a term used to describe an 194 address encoding in a packet. An address family that pertains to 195 addresses found in Data-Plane headers. See [AFN] and [RFC3232] 196 for details. An AFI value of 0 used in this specification 197 indicates an unspecified encoded address where the length of the 198 address is 0 octets following the 16-bit AFI value of 0. 200 Anycast Address: Anycast Address is a term used in this document to 201 refer to the same IPv4 or IPv6 address configured and used on 202 multiple systems at the same time. An EID or RLOC can be an 203 anycast address in each of their own address spaces. 205 Client-side: Client-side is a term used in this document to indicate 206 a connection initiation attempt by an end-system represented by an 207 EID. 209 Data-Probe: A Data-Probe is a LISP-encapsulated data packet where 210 the inner-header destination address equals the outer-header 211 destination address used to trigger a Map-Reply by a decapsulating 212 ETR. In addition, the original packet is decapsulated and 213 delivered to the destination host if the destination EID is in the 214 EID-Prefix range configured on the ETR. Otherwise, the packet is 215 discarded. A Data-Probe is used in some of the mapping database 216 designs to "probe" or request a Map-Reply from an ETR; in other 217 cases, Map-Requests are used. See each mapping database design 218 for details. When using Data-Probes, by sending Map-Requests on 219 the underlying routing system, EID-Prefixes must be advertised. 221 Egress Tunnel Router (ETR): An ETR is a router that accepts an IP 222 packet where the destination address in the "outer" IP header is 223 one of its own RLOCs. The router strips the "outer" header and 224 forwards the packet based on the next IP header found. In 225 general, an ETR receives LISP-encapsulated IP packets from the 226 Internet on one side and sends decapsulated IP packets to site 227 end-systems on the other side. ETR functionality does not have to 228 be limited to a router device. A server host can be the endpoint 229 of a LISP tunnel as well. 231 EID-to-RLOC Database: The EID-to-RLOC Database is a global 232 distributed database that contains all known EID-Prefix-to-RLOC 233 mappings. Each potential ETR typically contains a small piece of 234 the database: the EID-to-RLOC mappings for the EID-Prefixes 235 "behind" the router. These map to one of the router's own IP 236 addresses that are routable on the underlay. Note that there MAY 237 be transient conditions when the EID-Prefix for the site and 238 Locator-Set for each EID-Prefix may not be the same on all ETRs. 240 This has no negative implications, since a partial set of Locators 241 can be used. 243 EID-to-RLOC Map-Cache: The EID-to-RLOC Map-Cache is generally 244 short-lived, on-demand table in an ITR that stores, tracks, and is 245 responsible for timing out and otherwise validating EID-to-RLOC 246 mappings. This cache is distinct from the full "database" of EID- 247 to-RLOC mappings; it is dynamic, local to the ITR(s), and 248 relatively small, while the database is distributed, relatively 249 static, and much more global in scope to LISP nodes. 251 EID-Prefix: An EID-Prefix is a power-of-two block of EIDs that are 252 allocated to a site by an address allocation authority. EID- 253 Prefixes are associated with a set of RLOC addresses. EID-Prefix 254 allocations can be broken up into smaller blocks when an RLOC set 255 is to be associated with the larger EID-Prefix block. 257 End-System: An end-system is an IPv4 or IPv6 device that originates 258 packets with a single IPv4 or IPv6 header. The end-system 259 supplies an EID value for the destination address field of the IP 260 header when communicating outside of its routing domain. An end- 261 system can be a host computer, a switch or router device, or any 262 network appliance. 264 Endpoint ID (EID): An EID is a 32-bit (for IPv4) or 128-bit (for 265 IPv6) value used in the source and destination address fields of 266 the first (most inner) LISP header of a packet. The host obtains 267 a destination EID the same way it obtains a destination address 268 today, for example, through a Domain Name System (DNS) [RFC1034] 269 lookup or Session Initiation Protocol (SIP) [RFC3261] exchange. 270 The source EID is obtained via existing mechanisms used to set a 271 host's "local" IP address. An EID used on the public Internet 272 MUST have the same properties as any other IP address used in that 273 manner; this means, among other things, that it MUST be globally 274 unique. An EID is allocated to a host from an EID-Prefix block 275 associated with the site where the host is located. An EID can be 276 used by a host to refer to other hosts. Note that EID blocks MAY 277 be assigned in a hierarchical manner, independent of the network 278 topology, to facilitate scaling of the mapping database. In 279 addition, an EID block assigned to a site MAY have site-local 280 structure (subnetting) for routing within the site; this structure 281 is not visible to the underlay routing system. In theory, the bit 282 string that represents an EID for one device can represent an RLOC 283 for a different device. When used in discussions with other 284 Locator/ID separation proposals, a LISP EID will be called an 285 "LEID". Throughout this document, any references to "EID" refer 286 to an LEID. 288 Ingress Tunnel Router (ITR): An ITR is a router that resides in a 289 LISP site. Packets sent by sources inside of the LISP site to 290 destinations outside of the site are candidates for encapsulation 291 by the ITR. The ITR treats the IP destination address as an EID 292 and performs an EID-to-RLOC mapping lookup. The router then 293 prepends an "outer" IP header with one of its routable RLOCs (in 294 the RLOC space) in the source address field and the result of the 295 mapping lookup in the destination address field. Note that this 296 destination RLOC may be an intermediate, proxy device that has 297 better knowledge of the EID-to-RLOC mapping closer to the 298 destination EID. In general, an ITR receives IP packets from site 299 end-systems on one side and sends LISP-encapsulated IP packets 300 toward the Internet on the other side. 302 Specifically, when a service provider prepends a LISP header for 303 Traffic Engineering purposes, the router that does this is also 304 regarded as an ITR. The outer RLOC the ISP ITR uses can be based 305 on the outer destination address (the originating ITR's supplied 306 RLOC) or the inner destination address (the originating host's 307 supplied EID). 309 LISP Header: LISP header is a term used in this document to refer 310 to the outer IPv4 or IPv6 header, a UDP header, and a LISP- 311 specific 8-octet header that follow the UDP header and that an ITR 312 prepends or an ETR strips. 314 LISP Router: A LISP router is a router that performs the functions 315 of any or all of the following: ITR, ETR, RTR, Proxy-ITR (PITR), 316 or Proxy-ETR (PETR). 318 LISP Site: LISP site is a set of routers in an edge network that are 319 under a single technical administration. LISP routers that reside 320 in the edge network are the demarcation points to separate the 321 edge network from the core network. 323 Locator-Status-Bits (LSBs): Locator-Status-Bits are present in the 324 LISP header. They are used by ITRs to inform ETRs about the up/ 325 down status of all ETRs at the local site. These bits are used as 326 a hint to convey up/down router status and not path reachability 327 status. The LSBs can be verified by use of one of the Locator 328 reachability algorithms described in Section 10. An ETR MUST 329 rate-limit the action it takes when it detects changes in the 330 Locator-Status-Bits. 332 Negative Mapping Entry: A negative mapping entry, also known as a 333 negative cache entry, is an EID-to-RLOC entry where an EID-Prefix 334 is advertised or stored with no RLOCs. That is, the Locator-Set 335 for the EID-to-RLOC entry is empty, one with an encoded Locator 336 count of 0. This type of entry could be used to describe a prefix 337 from a non-LISP site, which is explicitly not in the mapping 338 database. There are a set of well-defined actions that are 339 encoded in a Negative Map-Reply. 341 Proxy-ETR (PETR): A PETR is defined and described in [RFC6832]. A 342 PETR acts like an ETR but does so on behalf of LISP sites that 343 send packets to destinations at non-LISP sites. 345 Proxy-ITR (PITR): A PITR is defined and described in [RFC6832]. A 346 PITR acts like an ITR but does so on behalf of non-LISP sites that 347 send packets to destinations at LISP sites. 349 Recursive Tunneling: Recursive Tunneling occurs when a packet has 350 more than one LISP IP header. Additional layers of tunneling MAY 351 be employed to implement Traffic Engineering or other re-routing 352 as needed. When this is done, an additional "outer" LISP header 353 is added, and the original RLOCs are preserved in the "inner" 354 header. 356 Re-Encapsulating Tunneling Router (RTR): An RTR acts like an ETR to 357 remove a LISP header, then acts as an ITR to prepend a new LISP 358 header. This is known as Re-encapsulating Tunneling. Doing this 359 allows a packet to be re-routed by the RTR without adding the 360 overhead of additional tunnel headers. When using multiple 361 mapping database systems, care must be taken to not create re- 362 encapsulation loops through misconfiguration. 364 Route-Returnability: Route-returnability is an assumption that the 365 underlying routing system will deliver packets to the destination. 366 When combined with a nonce that is provided by a sender and 367 returned by a receiver, this limits off-path data insertion. A 368 route-returnability check is verified when a message is sent with 369 a nonce, another message is returned with the same nonce, and the 370 destination of the original message appears as the source of the 371 returned message. 373 Routing Locator (RLOC): An RLOC is an IPv4 [RFC0791] or IPv6 374 [RFC8200] address of an Egress Tunnel Router (ETR). An RLOC is 375 the output of an EID-to-RLOC mapping lookup. An EID maps to zero 376 or more RLOCs. Typically, RLOCs are numbered from blocks that are 377 assigned to a site at each point to which it attaches to the 378 underlay network; where the topology is defined by the 379 connectivity of provider networks. Multiple RLOCs can be assigned 380 to the same ETR device or to multiple ETR devices at a site. 382 Server-side: Server-side is a term used in this document to indicate 383 that a connection initiation attempt is being accepted for a 384 destination EID. 386 TE-ETR: A TE-ETR is an ETR that is deployed in a service provider 387 network that strips an outer LISP header for Traffic Engineering 388 purposes. 390 TE-ITR: A TE-ITR is an ITR that is deployed in a service provider 391 network that prepends an additional LISP header for Traffic 392 Engineering purposes. 394 xTR: An xTR is a reference to an ITR or ETR when direction of data 395 flow is not part of the context description. "xTR" refers to the 396 router that is the tunnel endpoint and is used synonymously with 397 the term "Tunnel Router". For example, "An xTR can be located at 398 the Customer Edge (CE) router" indicates both ITR and ETR 399 functionality at the CE router. 401 4. Basic Overview 403 One key concept of LISP is that end-systems operate the same way they 404 do today. The IP addresses that hosts use for tracking sockets and 405 connections, and for sending and receiving packets, do not change. 406 In LISP terminology, these IP addresses are called Endpoint 407 Identifiers (EIDs). 409 Routers continue to forward packets based on IP destination 410 addresses. When a packet is LISP encapsulated, these addresses are 411 referred to as Routing Locators (RLOCs). Most routers along a path 412 between two hosts will not change; they continue to perform routing/ 413 forwarding lookups on the destination addresses. For routers between 414 the source host and the ITR as well as routers from the ETR to the 415 destination host, the destination address is an EID. For the routers 416 between the ITR and the ETR, the destination address is an RLOC. 418 Another key LISP concept is the "Tunnel Router". A Tunnel Router 419 prepends LISP headers on host-originated packets and strips them 420 prior to final delivery to their destination. The IP addresses in 421 this "outer header" are RLOCs. During end-to-end packet exchange 422 between two Internet hosts, an ITR prepends a new LISP header to each 423 packet, and an ETR strips the new header. The ITR performs EID-to- 424 RLOC lookups to determine the routing path to the ETR, which has the 425 RLOC as one of its IP addresses. 427 Some basic rules governing LISP are: 429 o End-systems only send to addresses that are EIDs. EIDs are 430 typically IP addresses assigned to hosts (other types of EID are 431 supported by LISP, see [RFC8060] for further information). End- 432 systems don't know that addresses are EIDs versus RLOCs but assume 433 that packets get to their intended destinations. In a system 434 where LISP is deployed, LISP routers intercept EID-addressed 435 packets and assist in delivering them across the network core 436 where EIDs cannot be routed. The procedure a host uses to send IP 437 packets does not change. 439 o LISP routers mostly deal with Routing Locator addresses. See 440 details in Section 4.1 to clarify what is meant by "mostly". 442 o RLOCs are always IP addresses assigned to routers, preferably 443 topologically oriented addresses from provider CIDR (Classless 444 Inter-Domain Routing) blocks. 446 o When a router originates packets, it MAY use as a source address 447 either an EID or RLOC. When acting as a host (e.g., when 448 terminating a transport session such as Secure SHell (SSH), 449 TELNET, or the Simple Network Management Protocol (SNMP)), it MAY 450 use an EID that is explicitly assigned for that purpose. An EID 451 that identifies the router as a host MUST NOT be used as an RLOC; 452 an EID is only routable within the scope of a site. A typical BGP 453 configuration might demonstrate this "hybrid" EID/RLOC usage where 454 a router could use its "host-like" EID to terminate iBGP sessions 455 to other routers in a site while at the same time using RLOCs to 456 terminate eBGP sessions to routers outside the site. 458 o Packets with EIDs in them are not expected to be delivered end-to- 459 end in the absence of an EID-to-RLOC mapping operation. They are 460 expected to be used locally for intra-site communication or to be 461 encapsulated for inter-site communication. 463 o EIDs MAY also be structured (subnetted) in a manner suitable for 464 local routing within an Autonomous System (AS). 466 An additional LISP header MAY be prepended to packets by a TE-ITR 467 when re-routing of the path for a packet is desired. A potential 468 use-case for this would be an ISP router that needs to perform 469 Traffic Engineering for packets flowing through its network. In such 470 a situation, termed "Recursive Tunneling", an ISP transit acts as an 471 additional ITR, and the destination RLOC it uses for the new 472 prepended header would be either a TE-ETR within the ISP (along an 473 intra-ISP traffic engineered path) or a TE-ETR within another ISP (an 474 inter-ISP traffic engineered path, where an agreement to build such a 475 path exists). 477 In order to avoid excessive packet overhead as well as possible 478 encapsulation loops, this document recommends that a maximum of two 479 LISP headers can be prepended to a packet. For initial LISP 480 deployments, it is assumed that two headers is sufficient, where the 481 first prepended header is used at a site for Location/Identity 482 separation and the second prepended header is used inside a service 483 provider for Traffic Engineering purposes. 485 Tunnel Routers can be placed fairly flexibly in a multi-AS topology. 486 For example, the ITR for a particular end-to-end packet exchange 487 might be the first-hop or default router within a site for the source 488 host. Similarly, the ETR might be the last-hop router directly 489 connected to the destination host. Another example, perhaps for a 490 VPN service outsourced to an ISP by a site, the ITR could be the 491 site's border router at the service provider attachment point. 492 Mixing and matching of site-operated, ISP-operated, and other Tunnel 493 Routers is allowed for maximum flexibility. 495 4.1. Packet Flow Sequence 497 This section provides an example of the unicast packet flow, 498 including also Control-Plane information as specified in 499 [I-D.ietf-lisp-rfc6833bis]. The example also assumes the following 500 conditions: 502 o Source host "host1.abc.example.com" is sending a packet to 503 "host2.xyz.example.com", exactly what host1 would do if the site 504 was not using LISP. 506 o Each site is multihomed, so each Tunnel Router has an address 507 (RLOC) assigned from the service provider address block for each 508 provider to which that particular Tunnel Router is attached. 510 o The ITR(s) and ETR(s) are directly connected to the source and 511 destination, respectively, but the source and destination can be 512 located anywhere in the LISP site. 514 o A Map-Request is sent for an external destination when the 515 destination is not found in the forwarding table or matches a 516 default route. Map-Requests are sent to the mapping database 517 system by using the LISP Control-Plane protocol documented in 518 [I-D.ietf-lisp-rfc6833bis]. 520 o Map-Replies are sent on the underlying routing system topology 521 using the [I-D.ietf-lisp-rfc6833bis] Control-Plane protocol. 523 Client host1.abc.example.com wants to communicate with server 524 host2.xyz.example.com: 526 1. host1.abc.example.com wants to open a TCP connection to 527 host2.xyz.example.com. It does a DNS lookup on 528 host2.xyz.example.com. An A/AAAA record is returned. This 529 address is the destination EID. The locally assigned address of 530 host1.abc.example.com is used as the source EID. An IPv4 or IPv6 531 packet is built and forwarded through the LISP site as a normal 532 IP packet until it reaches a LISP ITR. 534 2. The LISP ITR must be able to map the destination EID to an RLOC 535 of one of the ETRs at the destination site. The specific method 536 used to do this is not described in this example. See 537 [I-D.ietf-lisp-rfc6833bis] for further information. 539 3. The ITR sends a LISP Map-Request as specified in 540 [I-D.ietf-lisp-rfc6833bis]. Map-Requests SHOULD be rate-limited. 542 4. The mapping system helps forwarding the Map-Request to the 543 corresponding ETR. When the Map-Request arrives at one of the 544 ETRs at the destination site, it will process the packet as a 545 control message. 547 5. The ETR looks at the destination EID of the Map-Request and 548 matches it against the prefixes in the ETR's configured EID-to- 549 RLOC mapping database. This is the list of EID-Prefixes the ETR 550 is supporting for the site it resides in. If there is no match, 551 the Map-Request is dropped. Otherwise, a LISP Map-Reply is 552 returned to the ITR. 554 6. The ITR receives the Map-Reply message, parses the message (to 555 check for format validity), and stores the mapping information 556 from the packet. This information is stored in the ITR's EID-to- 557 RLOC Map-Cache. Note that the Map-Cache is an on-demand cache. 558 An ITR will manage its Map-Cache in such a way that optimizes for 559 its resource constraints. 561 7. Subsequent packets from host1.abc.example.com to 562 host2.xyz.example.com will have a LISP header prepended by the 563 ITR using the appropriate RLOC as the LISP header destination 564 address learned from the ETR. Note that the packet MAY be sent 565 to a different ETR than the one that returned the Map-Reply due 566 to the source site's hashing policy or the destination site's 567 Locator-Set policy. 569 8. The ETR receives these packets directly (since the destination 570 address is one of its assigned IP addresses), checks the validity 571 of the addresses, strips the LISP header, and forwards packets to 572 the attached destination host. 574 9. In order to defer the need for a mapping lookup in the reverse 575 direction, an ETR can OPTIONALLY create a cache entry that maps 576 the source EID (inner-header source IP address) to the source 577 RLOC (outer-header source IP address) in a received LISP packet. 578 Such a cache entry is termed a "glean mapping" and only contains 579 a single RLOC for the EID in question. More complete information 580 about additional RLOCs SHOULD be verified by sending a LISP Map- 581 Request for that EID. Both the ITR and the ETR MAY also 582 influence the decision the other makes in selecting an RLOC. 584 5. LISP Encapsulation Details 586 Since additional tunnel headers are prepended, the packet becomes 587 larger and can exceed the MTU of any link traversed from the ITR to 588 the ETR. It is RECOMMENDED in IPv4 that packets do not get 589 fragmented as they are encapsulated by the ITR. Instead, the packet 590 is dropped and an ICMP Unreachable/Fragmentation-Needed message is 591 returned to the source. 593 In the case when fragmentation is needed, this specification 594 RECOMMENDS that implementations provide support for one of the 595 proposed fragmentation and reassembly schemes. Two existing schemes 596 are detailed in Section 7. 598 Since IPv4 or IPv6 addresses can be either EIDs or RLOCs, the LISP 599 architecture supports IPv4 EIDs with IPv6 RLOCs (where the inner 600 header is in IPv4 packet format and the outer header is in IPv6 601 packet format) or IPv6 EIDs with IPv4 RLOCs (where the inner header 602 is in IPv6 packet format and the outer header is in IPv4 packet 603 format). The next sub-sections illustrate packet formats for the 604 homogeneous case (IPv4-in-IPv4 and IPv6-in-IPv6), but all 4 605 combinations MUST be supported. Additional types of EIDs are defined 606 in [RFC8060]. 608 As LISP uses UDP encapsulation to carry traffic between xTRs across 609 the Internet, implementors should be aware of the provisions of 610 [RFC8085], especially those given in section 3.1.11 on congestion 611 control for UDP tunneling. 613 Implementors are encouraged to consider UDP checksum usage guidelines 614 in section 3.4 of [RFC8085] when it is desirable to protect UDP and 615 LISP headers against corruption. 617 5.1. LISP IPv4-in-IPv4 Header Format 618 0 1 2 3 619 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 620 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 621 / |Version| IHL | DSCP |ECN| Total Length | 622 / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 623 | | Identification |Flags| Fragment Offset | 624 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 625 OH | Time to Live | Protocol = 17 | Header Checksum | 626 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 627 | | Source Routing Locator | 628 \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 629 \ | Destination Routing Locator | 630 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 631 / | Source Port = xxxx | Dest Port = 4341 | 632 UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 633 \ | UDP Length | UDP Checksum | 634 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 635 L |N|L|E|V|I|R|K|K| Nonce/Map-Version | 636 I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 637 S / | Instance ID/Locator-Status-Bits | 638 P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 639 / |Version| IHL | DSCP |ECN| Total Length | 640 / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 641 | | Identification |Flags| Fragment Offset | 642 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 643 IH | Time to Live | Protocol | Header Checksum | 644 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 645 | | Source EID | 646 \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 647 \ | Destination EID | 648 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 650 IHL = IP-Header-Length 652 5.2. LISP IPv6-in-IPv6 Header Format 654 0 1 2 3 655 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 656 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 657 / |Version| DSCP |ECN| Flow Label | 658 / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 659 | | Payload Length | Next Header=17| Hop Limit | 660 v +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 661 | | 662 O + + 663 u | | 664 t + Source Routing Locator + 665 e | | 666 r + + 667 | | 668 H +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 669 d | | 670 r + + 671 | | 672 ^ + Destination Routing Locator + 673 | | | 674 \ + + 675 \ | | 676 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 677 / | Source Port = xxxx | Dest Port = 4341 | 678 UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 679 \ | UDP Length | UDP Checksum | 680 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 681 L |N|L|E|V|I|R|K|K| Nonce/Map-Version | 682 I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 683 S / | Instance ID/Locator-Status-Bits | 684 P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 685 / |Version| DSCP |ECN| Flow Label | 686 / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 687 / | Payload Length | Next Header | Hop Limit | 688 v +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 689 | | 690 I + + 691 n | | 692 n + Source EID + 693 e | | 694 r + + 695 | | 696 H +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 697 d | | 698 r + + 699 | | 700 ^ + Destination EID + 701 \ | | 702 \ + + 703 \ | | 704 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 706 5.3. Tunnel Header Field Descriptions 708 Inner Header (IH): The inner header is the header on the 709 datagram received from the originating host [RFC0791] [RFC8200] 710 [RFC2474]. The source and destination IP addresses are EIDs. 712 Outer Header: (OH) The outer header is a new header prepended by an 713 ITR. The address fields contain RLOCs obtained from the ingress 714 router's EID-to-RLOC Cache. The IP protocol number is "UDP (17)" 715 from [RFC0768]. The setting of the Don't Fragment (DF) bit 716 'Flags' field is according to rules listed in Sections 7.1 and 717 7.2. 719 UDP Header: The UDP header contains an ITR selected source port when 720 encapsulating a packet. See Section 12 for details on the hash 721 algorithm used to select a source port based on the 5-tuple of the 722 inner header. The destination port MUST be set to the well-known 723 IANA-assigned port value 4341. 725 UDP Checksum: The 'UDP Checksum' field SHOULD be transmitted as zero 726 by an ITR for either IPv4 [RFC0768] and IPv6 encapsulation 727 [RFC6935] [RFC6936]. When a packet with a zero UDP checksum is 728 received by an ETR, the ETR MUST accept the packet for 729 decapsulation. When an ITR transmits a non-zero value for the UDP 730 checksum, it MUST send a correctly computed value in this field. 731 When an ETR receives a packet with a non-zero UDP checksum, it MAY 732 choose to verify the checksum value. If it chooses to perform 733 such verification, and the verification fails, the packet MUST be 734 silently dropped. If the ETR chooses not to perform the 735 verification, or performs the verification successfully, the 736 packet MUST be accepted for decapsulation. The handling of UDP 737 zero checksums over IPv6 for all tunneling protocols, including 738 LISP, is subject to the applicability statement in [RFC6936]. 740 UDP Length: The 'UDP Length' field is set for an IPv4-encapsulated 741 packet to be the sum of the inner-header IPv4 Total Length plus 742 the UDP and LISP header lengths. For an IPv6-encapsulated packet, 743 the 'UDP Length' field is the sum of the inner-header IPv6 Payload 744 Length, the size of the IPv6 header (40 octets), and the size of 745 the UDP and LISP headers. 747 N: The N-bit is the nonce-present bit. When this bit is set to 1, 748 the low-order 24 bits of the first 32 bits of the LISP header 749 contain a Nonce. See Section 10.1 for details. Both N- and 750 V-bits MUST NOT be set in the same packet. If they are, a 751 decapsulating ETR MUST treat the 'Nonce/Map-Version' field as 752 having a Nonce value present. 754 L: The L-bit is the 'Locator-Status-Bits' field enabled bit. When 755 this bit is set to 1, the Locator-Status-Bits in the second 756 32 bits of the LISP header are in use. 758 x 1 x x 0 x x x 759 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 760 |N|L|E|V|I|R|K|K| Nonce/Map-Version | 761 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 762 | Locator-Status-Bits | 763 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 765 E: The E-bit is the echo-nonce-request bit. This bit MUST be ignored 766 and has no meaning when the N-bit is set to 0. When the N-bit is 767 set to 1 and this bit is set to 1, an ITR is requesting that the 768 nonce value in the 'Nonce' field be echoed back in LISP- 769 encapsulated packets when the ITR is also an ETR. See 770 Section 10.1 for details. 772 V: The V-bit is the Map-Version present bit. When this bit is set to 773 1, the N-bit MUST be 0. Refer to Section 13.1 for more details. 774 This bit indicates that the LISP header is encoded in this 775 case as: 777 0 x 0 1 x x x x 778 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 779 |N|L|E|V|I|R|K|K| Source Map-Version | Dest Map-Version | 780 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 781 | Instance ID/Locator-Status-Bits | 782 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 784 I: The I-bit is the Instance ID bit. See Section 8 for more details. 785 When this bit is set to 1, the 'Locator-Status-Bits' field is 786 reduced to 8 bits and the high-order 24 bits are used as an 787 Instance ID. If the L-bit is set to 0, then the low-order 8 bits 788 are transmitted as zero and ignored on receipt. The format of the 789 LISP header would look like this: 791 x x x x 1 x x x 792 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 793 |N|L|E|V|I|R|K|K| Nonce/Map-Version | 794 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 795 | Instance ID | LSBs | 796 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 798 R: The R-bit is a Reserved and unassigned bit for future use. It 799 MUST be set to 0 on transmit and MUST be ignored on receipt. 801 KK: The KK-bits are a 2-bit field used when encapsulated packets are 802 encrypted. The field is set to 00 when the packet is not 803 encrypted. See [RFC8061] for further information. 805 LISP Nonce: The LISP 'Nonce' field is a 24-bit value that is 806 randomly generated by an ITR when the N-bit is set to 1. Nonce 807 generation algorithms are an implementation matter but are 808 required to generate different nonces when sending to different 809 RLOCs. However, the same nonce can be used for a period of time 810 when encapsulating to the same ETR. The nonce is also used when 811 the E-bit is set to request the nonce value to be echoed by the 812 other side when packets are returned. When the E-bit is clear but 813 the N-bit is set, a remote ITR is either echoing a previously 814 requested echo-nonce or providing a random nonce. See 815 Section 10.1 for more details. 817 LISP Locator-Status-Bits (LSBs): When the L-bit is also set, the 818 'Locator-Status-Bits' field in the LISP header is set by an ITR to 819 indicate to an ETR the up/down status of the Locators in the 820 source site. Each RLOC in a Map-Reply is assigned an ordinal 821 value from 0 to n-1 (when there are n RLOCs in a mapping entry). 822 The Locator-Status-Bits are numbered from 0 to n-1 from the least 823 significant bit of the field. The field is 32 bits when the I-bit 824 is set to 0 and is 8 bits when the I-bit is set to 1. When a 825 Locator-Status-Bit is set to 1, the ITR is indicating to the ETR 826 that the RLOC associated with the bit ordinal has up status. See 827 Section 10 for details on how an ITR can determine the status of 828 the ETRs at the same site. When a site has multiple EID-Prefixes 829 that result in multiple mappings (where each could have a 830 different Locator-Set), the Locator-Status-Bits setting in an 831 encapsulated packet MUST reflect the mapping for the EID-Prefix 832 that the inner-header source EID address matches. If the LSB for 833 an anycast Locator is set to 1, then there is at least one RLOC 834 with that address, and the ETR is considered 'up'. 836 When doing ITR/PITR encapsulation: 838 o The outer-header 'Time to Live' field (or 'Hop Limit' field, in 839 the case of IPv6) SHOULD be copied from the inner-header 'Time to 840 Live' field. 842 o The outer-header 'Differentiated Services Code Point' (DSCP) field 843 (or the 'Traffic Class' field, in the case of IPv6) SHOULD be 844 copied from the inner-header DSCP field ('Traffic Class' field, in 845 the case of IPv6) to the outer-header. 847 o The 'Explicit Congestion Notification' (ECN) field (bits 6 and 7 848 of the IPv6 'Traffic Class' field) requires special treatment in 849 order to avoid discarding indications of congestion [RFC6040]. 850 ITR encapsulation MUST copy the 2-bit 'ECN' field from the inner 851 header to the outer header. Re-encapsulation MUST copy the 2-bit 852 'ECN' field from the stripped outer header to the new outer 853 header. 855 When doing ETR/PETR decapsulation: 857 o The inner-header 'Time to Live' field (or 'Hop Limit' field, in 858 the case of IPv6) MUST be copied from the outer-header 'Time to 859 Live' field, when the Time to Live value of the outer header is 860 less than the Time to Live value of the inner header. Failing to 861 perform this check can cause the Time to Live of the inner header 862 to increment across encapsulation/decapsulation cycles. This 863 check is also performed when doing initial encapsulation, when a 864 packet comes to an ITR or PITR destined for a LISP site. 866 o The outer-header 'Differentiated Services Code Point' (DSCP) field 867 (or the 'Traffic Class' field, in the case of IPv6) SHOULD be 868 copied from the outer-header DSCP field ('Traffic Class' field, in 869 the case of IPv6) to the inner-header. 871 o The 'Explicit Congestion Notification' (ECN) field (bits 6 and 7 872 of the IPv6 'Traffic Class' field) requires special treatment in 873 order to avoid discarding indications of congestion [RFC6040]. If 874 the 'ECN' field contains a congestion indication codepoint (the 875 value is '11', the Congestion Experienced (CE) codepoint), then 876 ETR decapsulation MUST copy the 2-bit 'ECN' field from the 877 stripped outer header to the surviving inner header that is used 878 to forward the packet beyond the ETR. These requirements preserve 879 CE indications when a packet that uses ECN traverses a LISP tunnel 880 and becomes marked with a CE indication due to congestion between 881 the tunnel endpoints. Implementations exist that copy the 'ECN' 882 field from the outer header to the inner header even though 883 [RFC6040] does not recommend this behavior. It is RECOMMENDED 884 that implementations change to support the behavior in [RFC6040]. 886 Note that if an ETR/PETR is also an ITR/PITR and chooses to re- 887 encapsulate after decapsulating, the net effect of this is that the 888 new outer header will carry the same Time to Live as the old outer 889 header minus 1. 891 Copying the Time to Live (TTL) serves two purposes: first, it 892 preserves the distance the host intended the packet to travel; 893 second, and more importantly, it provides for suppression of looping 894 packets in the event there is a loop of concatenated tunnels due to 895 misconfiguration. 897 The Explicit Congestion Notification ('ECN') field occupies bits 6 898 and 7 of both the IPv4 'Type of Service' field and the IPv6 'Traffic 899 Class' field [RFC6040]. The 'ECN' field requires special treatment 900 in order to avoid discarding indications of congestion [RFC6040]. An 901 ITR/PITR encapsulation MUST copy the 2-bit 'ECN' field from the inner 902 header to the outer header. Re-encapsulation MUST copy the 2-bit 903 'ECN' field from the stripped outer header to the new outer header. 904 If the 'ECN' field contains a congestion indication codepoint (the 905 value is '11', the Congestion Experienced (CE) codepoint), then ETR/ 906 PETR decapsulation MUST copy the 2-bit 'ECN' field from the stripped 907 outer header to the surviving inner header that is used to forward 908 the packet beyond the ETR. These requirements preserve CE 909 indications when a packet that uses ECN traverses a LISP tunnel and 910 becomes marked with a CE indication due to congestion between the 911 tunnel endpoints. 913 6. LISP EID-to-RLOC Map-Cache 915 ITRs and PITRs maintain an on-demand cache, referred as LISP EID-to- 916 RLOC Map-Cache, that contains mappings from EID-prefixes to locator 917 sets. The cache is used to encapsulate packets from the EID space to 918 the corresponding RLOC network attachment point. 920 When an ITR/PITR receives a packet from inside of the LISP site to 921 destinations outside of the site a longest-prefix match lookup of the 922 EID is done to the Map-Cache. 924 When the lookup succeeds, the Locator-Set retrieved from the Map- 925 Cache is used to send the packet to the EID's topological location. 927 If the lookup fails, the ITR/PITR needs to retrieve the mapping using 928 the LISP Control-Plane protocol [I-D.ietf-lisp-rfc6833bis]. The 929 mapping is then stored in the local Map-Cache to forward subsequent 930 packets addressed to the same EID-prefix. 932 The Map-Cache is a local cache of mappings, entries are expired based 933 on the associated Time to live. In addition, entries can be updated 934 with more current information, see Section 13 for further information 935 on this. Finally, the Map-Cache also contains reachability 936 information about EIDs and RLOCs, and uses LISP reachability 937 information mechanisms to determine the reachability of RLOCs, see 938 Section 10 for the specific mechanisms. 940 7. Dealing with Large Encapsulated Packets 942 This section proposes two mechanisms to deal with packets that exceed 943 the path MTU between the ITR and ETR. 945 It is left to the implementor to decide if the stateless or stateful 946 mechanism SHOULD be implemented. Both or neither can be used, since 947 it is a local decision in the ITR regarding how to deal with MTU 948 issues, and sites can interoperate with differing mechanisms. 950 Both stateless and stateful mechanisms also apply to Re-encapsulating 951 and Recursive Tunneling, so any actions below referring to an ITR 952 also apply to a TE-ITR. 954 7.1. A Stateless Solution to MTU Handling 956 An ITR stateless solution to handle MTU issues is described as 957 follows: 959 1. Define H to be the size, in octets, of the outer header an ITR 960 prepends to a packet. This includes the UDP and LISP header 961 lengths. 963 2. Define L to be the size, in octets, of the maximum-sized packet 964 an ITR can send to an ETR without the need for the ITR or any 965 intermediate routers to fragment the packet. 967 3. Define an architectural constant S for the maximum size of a 968 packet, in octets, an ITR MUST receive from the source so the 969 effective MTU can be met. That is, L = S + H. 971 When an ITR receives a packet from a site-facing interface and adds H 972 octets worth of encapsulation to yield a packet size greater than L 973 octets (meaning the received packet size was greater than S octets 974 from the source), it resolves the MTU issue by first splitting the 975 original packet into 2 equal-sized fragments. A LISP header is then 976 prepended to each fragment. The size of the encapsulated fragments 977 is then (S/2 + H), which is less than the ITR's estimate of the path 978 MTU between the ITR and its correspondent ETR. 980 When an ETR receives encapsulated fragments, it treats them as two 981 individually encapsulated packets. It strips the LISP headers and 982 then forwards each fragment to the destination host of the 983 destination site. The two fragments are reassembled at the 984 destination host into the single IP datagram that was originated by 985 the source host. Note that reassembly can happen at the ETR if the 986 encapsulated packet was fragmented at or after the ITR. 988 This behavior MUST be performed by the ITR only when the source host 989 originates a packet with the 'DF' field of the IP header set to 0. 990 When the 'DF' field of the IP header is set to 1, or the packet is an 991 IPv6 packet originated by the source host, the ITR will drop the 992 packet when the size is greater than L and send an ICMPv4 ICMP 993 Unreachable/Fragmentation-Needed or ICMPv6 "Packet Too Big" message 994 to the source with a value of S, where S is (L - H). 996 When the outer-header encapsulation uses an IPv4 header, an 997 implementation SHOULD set the DF bit to 1 so ETR fragment reassembly 998 can be avoided. An implementation MAY set the DF bit in such headers 999 to 0 if it has good reason to believe there are unresolvable path MTU 1000 issues between the sending ITR and the receiving ETR. 1002 This specification RECOMMENDS that L be defined as 1500. 1004 7.2. A Stateful Solution to MTU Handling 1006 An ITR stateful solution to handle MTU issues is described as follows 1007 and was first introduced in [OPENLISP]: 1009 1. The ITR will keep state of the effective MTU for each Locator per 1010 Map-Cache entry. The effective MTU is what the core network can 1011 deliver along the path between the ITR and ETR. 1013 2. When an IPv6-encapsulated packet, or an IPv4-encapsulated packet 1014 with the DF bit set to 1, exceeds what the core network can 1015 deliver, one of the intermediate routers on the path will send an 1016 ICMPv6 "Packet Too Big" message or an ICMPv4 Unreachable/ 1017 Fragmentation-Needed to the ITR, respectively. The ITR will 1018 parse the ICMP message to determine which Locator is affected by 1019 the effective MTU change and then record the new effective MTU 1020 value in the Map-Cache entry. 1022 3. When a packet is received by the ITR from a source inside of the 1023 site and the size of the packet is greater than the effective MTU 1024 stored with the Map-Cache entry associated with the destination 1025 EID the packet is for, the ITR will send an ICMPv4 ICMP 1026 Unreachable/Fragmentation-Needed or ICMPv6 "Packet Too Big" 1027 message back to the source. The packet size advertised by the 1028 ITR in the ICMP message is the effective MTU minus the LISP 1029 encapsulation length. 1031 Even though this mechanism is stateful, it has advantages over the 1032 stateless IP fragmentation mechanism, by not involving the 1033 destination host with reassembly of ITR fragmented packets. 1035 8. Using Virtualization and Segmentation with LISP 1037 There are several cases where segregation is needed at the EID level. 1038 For instance, this is the case for deployments containing overlapping 1039 addresses, traffic isolation policies or multi-tenant virtualization. 1040 For these and other scenarios where segregation is needed, Instance 1041 IDs are used. 1043 An Instance ID can be carried in a LISP-encapsulated packet. An ITR 1044 that prepends a LISP header will copy a 24-bit value used by the LISP 1045 router to uniquely identify the address space. The value is copied 1046 to the 'Instance ID' field of the LISP header, and the I-bit is set 1047 to 1. 1049 When an ETR decapsulates a packet, the Instance ID from the LISP 1050 header is used as a table identifier to locate the forwarding table 1051 to use for the inner destination EID lookup. 1053 For example, an 802.1Q VLAN tag or VPN identifier could be used as a 1054 24-bit Instance ID. See [I-D.ietf-lisp-vpn] for LISP VPN use-case 1055 details. 1057 The Instance ID that is stored in the mapping database when LISP-DDT 1058 [RFC8111] is used is 32 bits in length. That means the Control-Plane 1059 can store more instances than a given Data-Plane can use. Multiple 1060 Data-Planes can use the same 32-bit space as long as the low-order 24 1061 bits don't overlap among xTRs. 1063 9. Routing Locator Selection 1065 The Map-Cache contains the state used by ITRs and PITRs to 1066 encapsulate packets. When an ITR/PITR receives a packet from inside 1067 the LISP site to a destination outside of the site a longest-prefix 1068 match lookup of the EID is done to the Map-Cache (see Section 6). 1069 The lookup returns a single Locator-Set containing a list of RLOCs 1070 corresponding to the EID's topological location. Each RLOC in the 1071 Locator-Set is associated with a 'Priority' and 'Weight', this 1072 information is used to select the RLOC to encapsulate. 1074 The RLOC with the lowest 'Priority' is selected. An RLOC with 1075 'Priority' 255 means that MUST NOT be used for forwarding. When 1076 multiple RLOC have the same 'Priority' then the 'Weight' states how 1077 to load balance traffic among them. The value of the 'Weight' 1078 represents the relative weight of the total packets that match the 1079 maping entry. 1081 The following are different scenarios for choosing RLOCs and the 1082 controls that are available: 1084 o The server-side returns one RLOC. The client-side can only use 1085 one RLOC. The server-side has complete control of the selection. 1087 o The server-side returns a list of RLOCs where a subset of the list 1088 has the same best Priority. The client can only use the subset 1089 list according to the weighting assigned by the server-side. In 1090 this case, the server-side controls both the subset list and load- 1091 splitting across its members. The client-side can use RLOCs 1092 outside of the subset list if it determines that the subset list 1093 is unreachable (unless RLOCs are set to a Priority of 255). Some 1094 sharing of control exists: the server-side determines the 1095 destination RLOC list and load distribution while the client-side 1096 has the option of using alternatives to this list if RLOCs in the 1097 list are unreachable. 1099 o The server-side sets a Weight of zero for the RLOC subset list. 1100 In this case, the client-side can choose how the traffic load is 1101 spread across the subset list. Control is shared by the server- 1102 side determining the list and the client-side determining load 1103 distribution. Again, the client can use alternative RLOCs if the 1104 server-provided list of RLOCs is unreachable. 1106 o Either side (more likely the server-side ETR) decides not to send 1107 a Map-Request. For example, if the server-side ETR does not send 1108 Map-Requests, it gleans RLOCs from the client-side ITR, giving the 1109 client-side ITR responsibility for bidirectional RLOC reachability 1110 and preferability. Server-side ETR gleaning of the client-side 1111 ITR RLOC is done by caching the inner-header source EID and the 1112 outer-header source RLOC of received packets. The client-side ITR 1113 controls how traffic is returned and can alternate using an outer- 1114 header source RLOC, which then can be added to the list the 1115 server-side ETR uses to return traffic. Since no Priority or 1116 Weights are provided using this method, the server-side ETR MUST 1117 assume that each client-side ITR RLOC uses the same best Priority 1118 with a Weight of zero. In addition, since EID-Prefix encoding 1119 cannot be conveyed in data packets, the EID-to-RLOC Cache on 1120 Tunnel Routers can grow to be very large. 1122 Instead of using the Map-Cache or mapping system, RLOC information 1123 MAY be gleaned from received tunneled packets or Map-Request 1124 messages. A "gleaned" Map-Cache entry, one learned from the source 1125 RLOC of a received encapsulated packet, is only stored and used for a 1126 few seconds, pending verification. Verification is performed by 1127 sending a Map-Request to the source EID (the inner-header IP source 1128 address) of the received encapsulated packet. A reply to this 1129 "verifying Map-Request" is used to fully populate the Map-Cache entry 1130 for the "gleaned" EID and is stored and used for the time indicated 1131 from the 'TTL' field of a received Map-Reply. When a verified Map- 1132 Cache entry is stored, data gleaning no longer occurs for subsequent 1133 packets that have a source EID that matches the EID-Prefix of the 1134 verified entry. This "gleaning" mechanism is OPTIONAL, refer to 1135 Section 16 for security issues regarding this mechanism. 1137 RLOCs that appear in EID-to-RLOC Map-Reply messages are assumed to be 1138 reachable when the R-bit [I-D.ietf-lisp-rfc6833bis] for the Locator 1139 record is set to 1. When the R-bit is set to 0, an ITR or PITR MUST 1140 NOT encapsulate to the RLOC. Neither the information contained in a 1141 Map-Reply nor that stored in the mapping database system provides 1142 reachability information for RLOCs. Note that reachability is not 1143 part of the mapping system and is determined using one or more of the 1144 Routing Locator reachability algorithms described in the next 1145 section. 1147 10. Routing Locator Reachability 1149 Several Data-Plane mechanisms for determining RLOC reachability are 1150 currently defined. Please note that additional Control-Plane based 1151 reachability mechanisms are defined in [I-D.ietf-lisp-rfc6833bis]. 1153 1. An ETR MAY examine the Locator-Status-Bits in the LISP header of 1154 an encapsulated data packet received from an ITR. If the ETR is 1155 also acting as an ITR and has traffic to return to the original 1156 ITR site, it can use this status information to help select an 1157 RLOC. 1159 2. When an ETR receives an encapsulated packet from an ITR, the 1160 source RLOC from the outer header of the packet is likely to be 1161 reachable. 1163 3. An ITR/ETR pair can use the 'Echo-Noncing' Locator reachability 1164 algorithms described in this section. 1166 When determining Locator up/down reachability by examining the 1167 Locator-Status-Bits from the LISP-encapsulated data packet, an ETR 1168 will receive up-to-date status from an encapsulating ITR about 1169 reachability for all ETRs at the site. CE-based ITRs at the source 1170 site can determine reachability relative to each other using the site 1171 IGP as follows: 1173 o Under normal circumstances, each ITR will advertise a default 1174 route into the site IGP. 1176 o If an ITR fails or if the upstream link to its PE fails, its 1177 default route will either time out or be withdrawn. 1179 Each ITR can thus observe the presence or lack of a default route 1180 originated by the others to determine the Locator-Status-Bits it sets 1181 for them. 1183 When ITRs at the site are not deployed in CE routers, the IGP can 1184 still be used to determine the reachability of Locators, provided 1185 they are injected into the IGP. This is typically done when a /32 1186 address is configured on a loopback interface. 1188 RLOCs listed in a Map-Reply are numbered with ordinals 0 to n-1. The 1189 Locator-Status-Bits in a LISP-encapsulated packet are numbered from 0 1190 to n-1 starting with the least significant bit. For example, if an 1191 RLOC listed in the 3rd position of the Map-Reply goes down (ordinal 1192 value 2), then all ITRs at the site will clear the 3rd least 1193 significant bit (xxxx x0xx) of the 'Locator-Status-Bits' field for 1194 the packets they encapsulate. 1196 When an ETR decapsulates a packet, it will check for any change in 1197 the 'Locator-Status-Bits' field. When a bit goes from 1 to 0, the 1198 ETR, if acting also as an ITR, will refrain from encapsulating 1199 packets to an RLOC that is indicated as down. It will only resume 1200 using that RLOC if the corresponding Locator-Status-Bit returns to a 1201 value of 1. Locator-Status-Bits are associated with a Locator-Set 1202 per EID-Prefix. Therefore, when a Locator becomes unreachable, the 1203 Locator-Status-Bit that corresponds to that Locator's position in the 1204 list returned by the last Map-Reply will be set to zero for that 1205 particular EID-Prefix. Refer to Section 16 for security related 1206 issues regarding Locator-Status-Bits. 1208 If an ITR encapsulates a packet to an ETR and the packet is received 1209 and decapsulated by the ETR, it is implied but not confirmed by the 1210 ITR that the ETR's RLOC is reachable. In most cases, the ETR can 1211 also reach the ITR but cannot assume this to be true, due to the 1212 possibility of path asymmetry. In the presence of unidirectional 1213 traffic flow from an ITR to an ETR, the ITR SHOULD NOT use the lack 1214 of return traffic as an indication that the ETR is unreachable. 1215 Instead, it MUST use an alternate mechanism to determine 1216 reachability. 1218 The security considerations of Section 16 related with data-plane 1219 reachability applies to the data-plane RLOC reachability mechanisms 1220 described in this section. 1222 10.1. Echo Nonce Algorithm 1224 When data flows bidirectionally between Locators from different 1225 sites, a Data-Plane mechanism called "nonce echoing" can be used to 1226 determine reachability between an ITR and ETR. When an ITR wants to 1227 solicit a nonce echo, it sets the N- and E-bits and places a 24-bit 1228 nonce [RFC4086] in the LISP header of the next encapsulated data 1229 packet. 1231 When this packet is received by the ETR, the encapsulated packet is 1232 forwarded as normal. When the ETR is an xTR (co-located as an ITR), 1233 it next sends a data packet to the ITR (when it is an xTR co-located 1234 as an ETR), it includes the nonce received earlier with the N-bit set 1235 and E-bit cleared. The ITR sees this "echoed nonce" and knows that 1236 the path to and from the ETR is up. 1238 The ITR will set the E-bit and N-bit for every packet it sends while 1239 in the echo-nonce-request state. The time the ITR waits to process 1240 the echoed nonce before it determines the path is unreachable is 1241 variable and is a choice left for the implementation. 1243 If the ITR is receiving packets from the ETR but does not see the 1244 nonce echoed while being in the echo-nonce-request state, then the 1245 path to the ETR is unreachable. This decision MAY be overridden by 1246 other Locator reachability algorithms. Once the ITR determines that 1247 the path to the ETR is down, it can switch to another Locator for 1248 that EID-Prefix. 1250 Note that "ITR" and "ETR" are relative terms here. Both devices MUST 1251 be implementing both ITR and ETR functionality for the echo nonce 1252 mechanism to operate. 1254 The ITR and ETR MAY both go into the echo-nonce-request state at the 1255 same time. The number of packets sent or the time during which echo 1256 nonce requests are sent is an implementation-specific setting. 1257 However, when an ITR is in the echo-nonce-request state, it can echo 1258 the ETR's nonce in the next set of packets that it encapsulates and 1259 subsequently continue sending echo-nonce-request packets. 1261 This mechanism does not completely solve the forward path 1262 reachability problem, as traffic may be unidirectional. That is, the 1263 ETR receiving traffic at a site MAY not be the same device as an ITR 1264 that transmits traffic from that site, or the site-to-site traffic is 1265 unidirectional so there is no ITR returning traffic. 1267 The echo-nonce algorithm is bilateral. That is, if one side sets the 1268 E-bit and the other side is not enabled for echo-noncing, then the 1269 echoing of the nonce does not occur and the requesting side may 1270 erroneously consider the Locator unreachable. An ITR SHOULD only set 1271 the E-bit in an encapsulated data packet when it knows the ETR is 1272 enabled for echo-noncing. This is conveyed by the E-bit in the RLOC- 1273 probe Map-Reply message. 1275 11. EID Reachability within a LISP Site 1277 A site MAY be multihomed using two or more ETRs. The hosts and 1278 infrastructure within a site will be addressed using one or more EID- 1279 Prefixes that are mapped to the RLOCs of the relevant ETRs in the 1280 mapping system. One possible failure mode is for an ETR to lose 1281 reachability to one or more of the EID-Prefixes within its own site. 1282 When this occurs when the ETR sends Map-Replies, it can clear the 1283 R-bit associated with its own Locator. And when the ETR is also an 1284 ITR, it can clear its Locator-Status-Bit in the encapsulation data 1285 header. 1287 It is recognized that there are no simple solutions to the site 1288 partitioning problem because it is hard to know which part of the 1289 EID-Prefix range is partitioned and which Locators can reach any sub- 1290 ranges of the EID-Prefixes. Note that this is not a new problem 1291 introduced by the LISP architecture. The problem exists today when a 1292 multihomed site uses BGP to advertise its reachability upstream. 1294 12. Routing Locator Hashing 1296 When an ETR provides an EID-to-RLOC mapping in a Map-Reply message 1297 that is stored in the Map-Cache of a requesting ITR, the Locator-Set 1298 for the EID-Prefix MAY contain different Priority and Weight values 1299 for each locator address. When more than one best Priority Locator 1300 exists, the ITR can decide how to load-share traffic against the 1301 corresponding Locators. 1303 The following hash algorithm MAY be used by an ITR to select a 1304 Locator for a packet destined to an EID for the EID-to-RLOC mapping: 1306 1. Either a source and destination address hash or the traditional 1307 5-tuple hash can be used. The traditional 5-tuple hash includes 1308 the source and destination addresses; source and destination TCP, 1309 UDP, or Stream Control Transmission Protocol (SCTP) port numbers; 1310 and the IP protocol number field or IPv6 next-protocol fields of 1311 a packet that a host originates from within a LISP site. When a 1312 packet is not a TCP, UDP, or SCTP packet, the source and 1313 destination addresses only from the header are used to compute 1314 the hash. 1316 2. Take the hash value and divide it by the number of Locators 1317 stored in the Locator-Set for the EID-to-RLOC mapping. 1319 3. The remainder will yield a value of 0 to "number of Locators 1320 minus 1". Use the remainder to select the Locator in the 1321 Locator-Set. 1323 The specific hash algorithm the ITR uses for load-sharing is out of 1324 scope for this document and does not prevent interoperability. 1326 Note that when a packet is LISP encapsulated, the source port number 1327 in the outer UDP header needs to be set. Selecting a hashed value 1328 allows core routers that are attached to Link Aggregation Groups 1329 (LAGs) to load-split the encapsulated packets across member links of 1330 such LAGs. Otherwise, core routers would see a single flow, since 1331 packets have a source address of the ITR, for packets that are 1332 originated by different EIDs at the source site. A suggested setting 1333 for the source port number computed by an ITR is a 5-tuple hash 1334 function on the inner header, as described above. The source port 1335 SHOULD be the same for all packets belonging to the same flow. 1337 Many core router implementations use a 5-tuple hash to decide how to 1338 balance packet load across members of a LAG. The 5-tuple hash 1339 includes the source and destination addresses of the packet and the 1340 source and destination ports when the protocol number in the packet 1341 is TCP or UDP. For this reason, UDP encoding is used for LISP 1342 encapsulation. 1344 13. Changing the Contents of EID-to-RLOC Mappings 1346 Since the LISP architecture uses a caching scheme to retrieve and 1347 store EID-to-RLOC mappings, the only way an ITR can get a more up-to- 1348 date mapping is to re-request the mapping. However, the ITRs do not 1349 know when the mappings change, and the ETRs do not keep track of 1350 which ITRs requested its mappings. For scalability reasons, it is 1351 desirable to maintain this approach but need to provide a way for 1352 ETRs to change their mappings and inform the sites that are currently 1353 communicating with the ETR site using such mappings. 1355 This section defines a Data-Plane mechanism for updating EID-to-RLOC 1356 mappings. Additionally, the Solicit-Map Request (SMR) Control-Plane 1357 updating mechanism is specified in [I-D.ietf-lisp-rfc6833bis]. 1359 When adding a new Locator record in lexicographic order to the end of 1360 a Locator-Set, it is easy to update mappings. We assume that new 1361 mappings will maintain the same Locator ordering as the old mapping 1362 but will just have new Locators appended to the end of the list. So, 1363 some ITRs can have a new mapping while other ITRs have only an old 1364 mapping that is used until they time out. When an ITR has only an 1365 old mapping but detects bits set in the Locator-Status-Bits that 1366 correspond to Locators beyond the list it has cached, it simply 1367 ignores them. However, this can only happen for locator addresses 1368 that are lexicographically greater than the locator addresses in the 1369 existing Locator-Set. 1371 When a Locator record is inserted in the middle of a Locator-Set, to 1372 maintain lexicographic order, SMR procedure 1373 [I-D.ietf-lisp-rfc6833bis] is used to inform ITRs and PITRs of the 1374 new Locator-Status-Bit mappings. 1376 When a Locator record is removed from a Locator-Set, ITRs that have 1377 the mapping cached will not use the removed Locator because the xTRs 1378 will set the Locator-Status-Bit to 0. So, even if the Locator is in 1379 the list, it will not be used. For new mapping requests, the xTRs 1380 can set the Locator AFI to 0 (indicating an unspecified address), as 1381 well as setting the corresponding Locator-Status-Bit to 0. This 1382 forces ITRs with old or new mappings to avoid using the removed 1383 Locator. 1385 If many changes occur to a mapping over a long period of time, one 1386 will find empty record slots in the middle of the Locator-Set and new 1387 records appended to the Locator-Set. At some point, it would be 1388 useful to compact the Locator-Set so the Locator-Status-Bit settings 1389 can be efficiently packed. 1391 We propose here a Data-Plane mechanism (Map-Versioning specified in 1392 [I-D.ietf-lisp-6834bis]) to update the contents of EID-to-RLOC 1393 mappings. Please note that in addition the Solicit-Map Request 1394 (specified in [I-D.ietf-lisp-rfc6833bis]) is a Control-Plane 1395 mechanisms that can be used to update EID-to-RLOC mappings. 1397 13.1. Database Map-Versioning 1399 When there is unidirectional packet flow between an ITR and ETR, and 1400 the EID-to-RLOC mappings change on the ETR, it needs to inform the 1401 ITR so encapsulation to a removed Locator can stop and can instead be 1402 started to a new Locator in the Locator-Set. 1404 An ETR, when it sends Map-Reply messages, conveys its own Map-Version 1405 Number. This is known as the Destination Map-Version Number. ITRs 1406 include the Destination Map-Version Number in packets they 1407 encapsulate to the site. When an ETR decapsulates a packet and 1408 detects that the Destination Map-Version Number is less than the 1409 current version for its mapping, the SMR procedure described in 1410 [I-D.ietf-lisp-rfc6833bis] occurs. 1412 An ITR, when it encapsulates packets to ETRs, can convey its own Map- 1413 Version Number. This is known as the Source Map-Version Number. 1414 When an ETR decapsulates a packet and detects that the Source Map- 1415 Version Number is greater than the last Map-Version Number sent in a 1416 Map-Reply from the ITR's site, the ETR will send a Map-Request to one 1417 of the ETRs for the source site. 1419 A Map-Version Number is used as a sequence number per EID-Prefix, so 1420 values that are greater are considered to be more recent. A value of 1421 0 for the Source Map-Version Number or the Destination Map-Version 1422 Number conveys no versioning information, and an ITR does no 1423 comparison with previously received Map-Version Numbers. 1425 A Map-Version Number can be included in Map-Register messages as 1426 well. This is a good way for the Map-Server to assure that all ETRs 1427 for a site registering to it will be synchronized according to Map- 1428 Version Number. 1430 See [I-D.ietf-lisp-6834bis] for a more detailed analysis and 1431 description of Database Map-Versioning. 1433 14. Multicast Considerations 1435 A multicast group address, as defined in the original Internet 1436 architecture, is an identifier of a grouping of topologically 1437 independent receiver host locations. The address encoding itself 1438 does not determine the location of the receiver(s). The multicast 1439 routing protocol, and the network-based state the protocol creates, 1440 determine where the receivers are located. 1442 In the context of LISP, a multicast group address is both an EID and 1443 a Routing Locator. Therefore, no specific semantic or action needs 1444 to be taken for a destination address, as it would appear in an IP 1445 header. Therefore, a group address that appears in an inner IP 1446 header built by a source host will be used as the destination EID. 1447 The outer IP header (the destination Routing Locator address), 1448 prepended by a LISP router, can use the same group address as the 1449 destination Routing Locator, use a multicast or unicast Routing 1450 Locator obtained from a Mapping System lookup, or use other means to 1451 determine the group address mapping. 1453 With respect to the source Routing Locator address, the ITR prepends 1454 its own IP address as the source address of the outer IP header. 1455 Just like it would if the destination EID was a unicast address. 1456 This source Routing Locator address, like any other Routing Locator 1457 address, MUST be routable on the underlay. 1459 There are two approaches for LISP-Multicast, one that uses native 1460 multicast routing in the underlay with no support from the Mapping 1461 System and the other that uses only unicast routing in the underlay 1462 with support from the Mapping System. See [RFC6831] and [RFC8378], 1463 respectively, for details. Details for LISP-Multicast and 1464 interworking with non-LISP sites are described in [RFC6831] and 1465 [RFC6832]. 1467 15. Router Performance Considerations 1469 LISP is designed to be very "hardware-based forwarding friendly". A 1470 few implementation techniques can be used to incrementally implement 1471 LISP: 1473 o When a tunnel-encapsulated packet is received by an ETR, the outer 1474 destination address may not be the address of the router. This 1475 makes it challenging for the control plane to get packets from the 1476 hardware. This may be mitigated by creating special Forwarding 1477 Information Base (FIB) entries for the EID-Prefixes of EIDs served 1478 by the ETR (those for which the router provides an RLOC 1479 translation). These FIB entries are marked with a flag indicating 1480 that Control-Plane processing SHOULD be performed. The forwarding 1481 logic of testing for particular IP protocol number values is not 1482 necessary. There are a few proven cases where no changes to 1483 existing deployed hardware were needed to support the LISP Data- 1484 Plane. 1486 o On an ITR, prepending a new IP header consists of adding more 1487 octets to a MAC rewrite string and prepending the string as part 1488 of the outgoing encapsulation procedure. Routers that support 1489 Generic Routing Encapsulation (GRE) tunneling [RFC2784] or 6to4 1490 tunneling [RFC3056] may already support this action. 1492 o A packet's source address or interface the packet was received on 1493 can be used to select VRF (Virtual Routing/Forwarding). The VRF's 1494 routing table can be used to find EID-to-RLOC mappings. 1496 For performance issues related to Map-Cache management, see 1497 Section 16. 1499 16. Security Considerations 1501 A complete LISP threat analysis can be found in [RFC7835]. In what 1502 follows we highlight security considerations that apply when LISP is 1503 deployed in environments such as those specified in Section 1.1. 1505 The optional mechanisms of gleaning is offered to directly obtain a 1506 mapping from the LISP encapsulated packets. Specifically, an xTR can 1507 learn the EID-to-RLOC mapping by inspecting the source RLOC and 1508 source EID of an encapsulated packet, and insert this new mapping 1509 into its Map-Cache. An off-path attacker can spoof the source EID 1510 address to divert the traffic sent to the victim's spoofed EID. If 1511 the attacker spoofs the source RLOC, it can mount a DoS attack by 1512 redirecting traffic to the spoofed victim's RLOC, potentially 1513 overloading it. 1515 The LISP Data-Plane defines several mechanisms to monitor RLOC Data- 1516 Plane reachability, in this context Locator-Status Bits, Nonce- 1517 Present and Echo-Nonce bits of the LISP encapsulation header can be 1518 manipulated by an attacker to mount a DoS attack. An off-path 1519 attacker able to spoof the RLOC and/or nonce of a victim's xTR can 1520 manipulate such mechanisms to declare false information about the 1521 RLOC's reachability status. 1523 As an exmple of such attacks an off-path attacker can exploit the 1524 echo-nonce mechanism by sending data packets to an ITR with a random 1525 nonce from an ETR's spoofed RLOC. Note the attacker must guess a 1526 valid nonce the ITR is requesting to be echoed within a small window 1527 of time. The goal is to convince the ITR that the ETR's RLOC is 1528 reachable even when it may not be reachable. If the attack is 1529 successful, the ITR believes the wrong reachability status of the 1530 ETR's RLOC until RLOC-probing detects the correct status. This time 1531 frame is on the order of 10s of seconds. This specific attack can be 1532 mitigated by preventing RLOC spoofing in the network by deploying 1533 uRPF BCP 38 [RFC2827]. In addition and in order to exploit this 1534 vulnerability, the off-path attacker must send echo-nonce packets at 1535 high rate. If the nonces have never been requested by the ITR, it 1536 can protect itself from erroneious reachability attacks. 1538 Map-Versioning is a Data-Plane mechanism used to signal a peering xTR 1539 that a local EID-to-RLOC mapping has been updated, so that the 1540 peering xTR uses LISP Control-Plane signaling message to retrieve a 1541 fresh mapping. This can be used by an attacker to forge the map- 1542 versioning field of a LISP encapsulated header and force an excessive 1543 amount of signaling between xTRs that may overload them. 1545 Most of the attack vectors can be mitigated with careful deployment 1546 and configuration, information learned opportunistically (such as LSB 1547 or gleaning) SHOULD be verified with other reachability mechanisms. 1548 In addition, systematic rate-limitation and filtering is an effective 1549 technique to mitigate attacks that aim to overload the Control-Plane. 1551 17. Network Management Considerations 1553 Considerations for network management tools exist so the LISP 1554 protocol suite can be operationally managed. These mechanisms can be 1555 found in [RFC7052] and [RFC6835]. 1557 18. Changes since RFC 6830 1559 For implementation considerations, the following changes have been 1560 made to this document since RFC 6830 was published: 1562 o It is no longer mandated that a maximum number of 2 LISP headers 1563 be prepended to a packet. If there is a application need for more 1564 than 2 LISP headers, an implementation can support more. However, 1565 it is RECOMMENDED that a maximum of two LISP headers can be 1566 prepended to a packet. 1568 o The 3 reserved flag bits in the LISP header have been allocated 1569 for [RFC8061]. The low-order 2 bits of the 3-bit field (now named 1570 the KK bits) are used as a key identifier. The 1 remaining bit is 1571 still documented as reserved and unassigned. 1573 o Data-Plane gleaning for creating map-cache entries has been made 1574 optional. Any ITR implementations that depend on or assume the 1575 remote ETR is gleaning should not do so. This does not create any 1576 interoperability problems since the control-plane map-cache 1577 population procedures are unilateral and are the typical method 1578 for map-cache population. 1580 o The bulk of the changes to this document which reduces its length 1581 are due to moving the LISP control-plane messaging and procedures 1582 to [I-D.ietf-lisp-rfc6833bis]. 1584 19. IANA Considerations 1586 This section provides guidance to the Internet Assigned Numbers 1587 Authority (IANA) regarding registration of values related to this 1588 Data-Plane LISP specification, in accordance with BCP 26 [RFC8126]. 1590 19.1. LISP UDP Port Numbers 1592 The IANA registry has allocated UDP port number 4341 for the LISP 1593 Data-Plane. IANA has updated the description for UDP port 4341 as 1594 follows: 1596 lisp-data 4341 udp LISP Data Packets 1598 20. References 1600 20.1. Normative References 1602 [I-D.ietf-lisp-6834bis] 1603 Iannone, L., Saucez, D., and O. Bonaventure, "Locator/ID 1604 Separation Protocol (LISP) Map-Versioning", draft-ietf- 1605 lisp-6834bis-02 (work in progress), September 2018. 1607 [I-D.ietf-lisp-rfc6833bis] 1608 Fuller, V., Farinacci, D., and A. Cabellos-Aparicio, 1609 "Locator/ID Separation Protocol (LISP) Control-Plane", 1610 draft-ietf-lisp-rfc6833bis-19 (work in progress), October 1611 2018. 1613 [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, 1614 DOI 10.17487/RFC0768, August 1980, 1615 . 1617 [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, 1618 DOI 10.17487/RFC0791, September 1981, 1619 . 1621 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1622 Requirement Levels", BCP 14, RFC 2119, 1623 DOI 10.17487/RFC2119, March 1997, 1624 . 1626 [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, 1627 "Definition of the Differentiated Services Field (DS 1628 Field) in the IPv4 and IPv6 Headers", RFC 2474, 1629 DOI 10.17487/RFC2474, December 1998, 1630 . 1632 [RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering: 1633 Defeating Denial of Service Attacks which employ IP Source 1634 Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827, 1635 May 2000, . 1637 [RFC6040] Briscoe, B., "Tunnelling of Explicit Congestion 1638 Notification", RFC 6040, DOI 10.17487/RFC6040, November 1639 2010, . 1641 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1642 Writing an IANA Considerations Section in RFCs", BCP 26, 1643 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1644 . 1646 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1647 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1648 May 2017, . 1650 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1651 (IPv6) Specification", STD 86, RFC 8200, 1652 DOI 10.17487/RFC8200, July 2017, 1653 . 1655 20.2. Informative References 1657 [AFN] IANA, "Address Family Numbers", August 2016, 1658 . 1660 [CHIAPPA] Chiappa, J., "Endpoints and Endpoint names: A Proposed", 1661 1999, 1662 . 1664 [I-D.ietf-lisp-introduction] 1665 Cabellos-Aparicio, A. and D. Saucez, "An Architectural 1666 Introduction to the Locator/ID Separation Protocol 1667 (LISP)", draft-ietf-lisp-introduction-13 (work in 1668 progress), April 2015. 1670 [I-D.ietf-lisp-vpn] 1671 Moreno, V. and D. Farinacci, "LISP Virtual Private 1672 Networks (VPNs)", draft-ietf-lisp-vpn-02 (work in 1673 progress), May 2018. 1675 [OPENLISP] 1676 Iannone, L., Saucez, D., and O. Bonaventure, "OpenLISP 1677 Implementation Report", Work in Progress, July 2008. 1679 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 1680 STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, 1681 . 1683 [RFC1918] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G., 1684 and E. Lear, "Address Allocation for Private Internets", 1685 BCP 5, RFC 1918, DOI 10.17487/RFC1918, February 1996, 1686 . 1688 [RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. 1689 Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, 1690 DOI 10.17487/RFC2784, March 2000, 1691 . 1693 [RFC3056] Carpenter, B. and K. Moore, "Connection of IPv6 Domains 1694 via IPv4 Clouds", RFC 3056, DOI 10.17487/RFC3056, February 1695 2001, . 1697 [RFC3232] Reynolds, J., Ed., "Assigned Numbers: RFC 1700 is Replaced 1698 by an On-line Database", RFC 3232, DOI 10.17487/RFC3232, 1699 January 2002, . 1701 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, 1702 A., Peterson, J., Sparks, R., Handley, M., and E. 1703 Schooler, "SIP: Session Initiation Protocol", RFC 3261, 1704 DOI 10.17487/RFC3261, June 2002, 1705 . 1707 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 1708 "Randomness Requirements for Security", BCP 106, RFC 4086, 1709 DOI 10.17487/RFC4086, June 2005, 1710 . 1712 [RFC4984] Meyer, D., Ed., Zhang, L., Ed., and K. Fall, Ed., "Report 1713 from the IAB Workshop on Routing and Addressing", 1714 RFC 4984, DOI 10.17487/RFC4984, September 2007, 1715 . 1717 [RFC6831] Farinacci, D., Meyer, D., Zwiebel, J., and S. Venaas, "The 1718 Locator/ID Separation Protocol (LISP) for Multicast 1719 Environments", RFC 6831, DOI 10.17487/RFC6831, January 1720 2013, . 1722 [RFC6832] Lewis, D., Meyer, D., Farinacci, D., and V. Fuller, 1723 "Interworking between Locator/ID Separation Protocol 1724 (LISP) and Non-LISP Sites", RFC 6832, 1725 DOI 10.17487/RFC6832, January 2013, 1726 . 1728 [RFC6835] Farinacci, D. and D. Meyer, "The Locator/ID Separation 1729 Protocol Internet Groper (LIG)", RFC 6835, 1730 DOI 10.17487/RFC6835, January 2013, 1731 . 1733 [RFC6935] Eubanks, M., Chimento, P., and M. Westerlund, "IPv6 and 1734 UDP Checksums for Tunneled Packets", RFC 6935, 1735 DOI 10.17487/RFC6935, April 2013, 1736 . 1738 [RFC6936] Fairhurst, G. and M. Westerlund, "Applicability Statement 1739 for the Use of IPv6 UDP Datagrams with Zero Checksums", 1740 RFC 6936, DOI 10.17487/RFC6936, April 2013, 1741 . 1743 [RFC7052] Schudel, G., Jain, A., and V. Moreno, "Locator/ID 1744 Separation Protocol (LISP) MIB", RFC 7052, 1745 DOI 10.17487/RFC7052, October 2013, 1746 . 1748 [RFC7215] Jakab, L., Cabellos-Aparicio, A., Coras, F., Domingo- 1749 Pascual, J., and D. Lewis, "Locator/Identifier Separation 1750 Protocol (LISP) Network Element Deployment 1751 Considerations", RFC 7215, DOI 10.17487/RFC7215, April 1752 2014, . 1754 [RFC7833] Howlett, J., Hartman, S., and A. Perez-Mendez, Ed., "A 1755 RADIUS Attribute, Binding, Profiles, Name Identifier 1756 Format, and Confirmation Methods for the Security 1757 Assertion Markup Language (SAML)", RFC 7833, 1758 DOI 10.17487/RFC7833, May 2016, 1759 . 1761 [RFC7835] Saucez, D., Iannone, L., and O. Bonaventure, "Locator/ID 1762 Separation Protocol (LISP) Threat Analysis", RFC 7835, 1763 DOI 10.17487/RFC7835, April 2016, 1764 . 1766 [RFC8060] Farinacci, D., Meyer, D., and J. Snijders, "LISP Canonical 1767 Address Format (LCAF)", RFC 8060, DOI 10.17487/RFC8060, 1768 February 2017, . 1770 [RFC8061] Farinacci, D. and B. Weis, "Locator/ID Separation Protocol 1771 (LISP) Data-Plane Confidentiality", RFC 8061, 1772 DOI 10.17487/RFC8061, February 2017, 1773 . 1775 [RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage 1776 Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085, 1777 March 2017, . 1779 [RFC8111] Fuller, V., Lewis, D., Ermagan, V., Jain, A., and A. 1780 Smirnov, "Locator/ID Separation Protocol Delegated 1781 Database Tree (LISP-DDT)", RFC 8111, DOI 10.17487/RFC8111, 1782 May 2017, . 1784 [RFC8378] Moreno, V. and D. Farinacci, "Signal-Free Locator/ID 1785 Separation Protocol (LISP) Multicast", RFC 8378, 1786 DOI 10.17487/RFC8378, May 2018, 1787 . 1789 Appendix A. Acknowledgments 1791 An initial thank you goes to Dave Oran for planting the seeds for the 1792 initial ideas for LISP. His consultation continues to provide value 1793 to the LISP authors. 1795 A special and appreciative thank you goes to Noel Chiappa for 1796 providing architectural impetus over the past decades on separation 1797 of location and identity, as well as detailed reviews of the LISP 1798 architecture and documents, coupled with enthusiasm for making LISP a 1799 practical and incremental transition for the Internet. 1801 The original authors would like to gratefully acknowledge many people 1802 who have contributed discussions and ideas to the making of this 1803 proposal. They include Scott Brim, Andrew Partan, John Zwiebel, 1804 Jason Schiller, Lixia Zhang, Dorian Kim, Peter Schoenmaker, Vijay 1805 Gill, Geoff Huston, David Conrad, Mark Handley, Ron Bonica, Ted 1806 Seely, Mark Townsley, Chris Morrow, Brian Weis, Dave McGrew, Peter 1807 Lothberg, Dave Thaler, Eliot Lear, Shane Amante, Ved Kafle, Olivier 1808 Bonaventure, Luigi Iannone, Robin Whittle, Brian Carpenter, Joel 1809 Halpern, Terry Manderson, Roger Jorgensen, Ran Atkinson, Stig Venaas, 1810 Iljitsch van Beijnum, Roland Bless, Dana Blair, Bill Lynch, Marc 1811 Woolward, Damien Saucez, Damian Lezama, Attilla De Groot, Parantap 1812 Lahiri, David Black, Roque Gagliano, Isidor Kouvelas, Jesper Skriver, 1813 Fred Templin, Margaret Wasserman, Sam Hartman, Michael Hofling, Pedro 1814 Marques, Jari Arkko, Gregg Schudel, Srinivas Subramanian, Amit Jain, 1815 Xu Xiaohu, Dhirendra Trivedi, Yakov Rekhter, John Scudder, John 1816 Drake, Dimitri Papadimitriou, Ross Callon, Selina Heimlich, Job 1817 Snijders, Vina Ermagan, Fabio Maino, Victor Moreno, Chris White, 1818 Clarence Filsfils, Alia Atlas, Florin Coras and Alberto Rodriguez. 1820 This work originated in the Routing Research Group (RRG) of the IRTF. 1821 An individual submission was converted into the IETF LISP working 1822 group document that became this RFC. 1824 The LISP working group would like to give a special thanks to Jari 1825 Arkko, the Internet Area AD at the time that the set of LISP 1826 documents were being prepared for IESG last call, and for his 1827 meticulous reviews and detailed commentaries on the 7 working group 1828 last call documents progressing toward standards-track RFCs. 1830 The current authors would like to give a sincere thank you to the 1831 people who help put LISP on standards track in the IETF. They 1832 include Joel Halpern, Luigi Iannone, Deborah Brungard, Fabio Maino, 1833 Scott Bradner, Kyle Rose, Takeshi Takahashi, Sarah Banks, Pete 1834 Resnick, Colin Perkins, Mirja Kuhlewind, Francis Dupont, Benjamin 1835 Kaduk, Eric Rescorla, Alvaro Retana, Alexey Melnikov, Alissa Cooper, 1836 Suresh Krishnan, Alberto Rodriguez-Natal, Vina Ermagen, Mohamed 1837 Boucadair, Brian Trammell, Sabrina Tanamal, and John Drake. The 1838 contributions they offered greatly added to the security, scale, and 1839 robustness of the LISP architecture and protocols. 1841 Appendix B. Document Change Log 1843 [RFC Editor: Please delete this section on publication as RFC.] 1845 B.1. Changes to draft-ietf-lisp-rfc6830bis-26 1847 o Posted late October 2018. 1849 o Changed description about "reserved" bits to state "reserved and 1850 unassigned". 1852 B.2. Changes to draft-ietf-lisp-rfc6830bis-25 1854 o Posted mid October 2018. 1856 o Added more to the Security Considerations section with discussion 1857 about echo-nonce attacks. 1859 B.3. Changes to draft-ietf-lisp-rfc6830bis-24 1861 o Posted mid October 2018. 1863 o Final editorial changes for Eric and Ben. 1865 B.4. Changes to draft-ietf-lisp-rfc6830bis-23 1867 o Posted early October 2018. 1869 o Added an applicability statement in section 1 to address security 1870 concerns from Telechat. 1872 B.5. Changes to draft-ietf-lisp-rfc6830bis-22 1874 o Posted early October 2018. 1876 o Changes to reflect comments post Telechat. 1878 B.6. Changes to draft-ietf-lisp-rfc6830bis-21 1880 o Posted late-September 2018. 1882 o Changes to reflect comments from Sep 27th Telechat. 1884 B.7. Changes to draft-ietf-lisp-rfc6830bis-20 1886 o Posted late-September 2018. 1888 o Fix old reference to RFC3168, changed to RFC6040. 1890 B.8. Changes to draft-ietf-lisp-rfc6830bis-19 1892 o Posted late-September 2018. 1894 o More editorial changes. 1896 B.9. Changes to draft-ietf-lisp-rfc6830bis-18 1898 o Posted mid-September 2018. 1900 o Changes to reflect comments from Secdir review (Mirja). 1902 B.10. Changes to draft-ietf-lisp-rfc6830bis-17 1904 o Posted September 2018. 1906 o Indicate in the "Changes since RFC 6830" section why the document 1907 has been shortened in length. 1909 o Make reference to RFC 8085 about UDP congestion control. 1911 o More editorial changes from multiple IESG reviews. 1913 B.11. Changes to draft-ietf-lisp-rfc6830bis-16 1915 o Posted late August 2018. 1917 o Distinguish the message type names between ICMP for IPv4 and ICMP 1918 for IPv6 for handling MTU issues. 1920 B.12. Changes to draft-ietf-lisp-rfc6830bis-15 1922 o Posted August 2018. 1924 o Final editorial changes before RFC submission for Proposed 1925 Standard. 1927 o Added section "Changes since RFC 6830" so implementers are 1928 informed of any changes since the last RFC publication. 1930 B.13. Changes to draft-ietf-lisp-rfc6830bis-14 1932 o Posted July 2018 IETF week. 1934 o Put obsolete of RFC 6830 in Intro section in addition to abstract. 1936 B.14. Changes to draft-ietf-lisp-rfc6830bis-13 1938 o Posted March IETF Week 2018. 1940 o Clarified that a new nonce is required per RLOC. 1942 o Removed 'Clock Sweep' section. This text must be placed in a new 1943 OAM document. 1945 o Some references changed from normative to informative 1947 B.15. Changes to draft-ietf-lisp-rfc6830bis-12 1949 o Posted July 2018. 1951 o Fixed Luigi editorial comments to ready draft for RFC status. 1953 B.16. Changes to draft-ietf-lisp-rfc6830bis-11 1955 o Posted March 2018. 1957 o Removed sections 16, 17 and 18 (Mobility, Deployment and 1958 Traceroute considerations). This text must be placed in a new OAM 1959 document. 1961 B.17. Changes to draft-ietf-lisp-rfc6830bis-10 1963 o Posted March 2018. 1965 o Updated section 'Router Locator Selection' stating that the Data- 1966 Plane MUST follow what's stored in the Map-Cache (priorities and 1967 weights). 1969 o Section 'Routing Locator Reachability': Removed bullet point 2 1970 (ICMP Network/Host Unreachable),3 (hints from BGP),4 (ICMP Port 1971 Unreachable),5 (receive a Map-Reply as a response) and RLOC 1972 probing 1974 o Removed 'Solicit-Map Request'. 1976 B.18. Changes to draft-ietf-lisp-rfc6830bis-09 1978 o Posted January 2018. 1980 o Add more details in section 5.3 about DSCP processing during 1981 encapsulation and decapsulation. 1983 o Added clarity to definitions in the Definition of Terms section 1984 from various commenters. 1986 o Removed PA and PI definitions from Definition of Terms section. 1988 o More editorial changes. 1990 o Removed 4342 from IANA section and move to RFC6833 IANA section. 1992 B.19. Changes to draft-ietf-lisp-rfc6830bis-08 1994 o Posted January 2018. 1996 o Remove references to research work for any protocol mechanisms. 1998 o Document scanned to make sure it is RFC 2119 compliant. 2000 o Made changes to reflect comments from document WG shepherd Luigi 2001 Iannone. 2003 o Ran IDNITs on the document. 2005 B.20. Changes to draft-ietf-lisp-rfc6830bis-07 2007 o Posted November 2017. 2009 o Rephrase how Instance-IDs are used and don't refer to [RFC1918] 2010 addresses. 2012 B.21. Changes to draft-ietf-lisp-rfc6830bis-06 2014 o Posted October 2017. 2016 o Put RTR definition before it is used. 2018 o Rename references that are now working group drafts. 2020 o Remove "EIDs MUST NOT be used as used by a host to refer to other 2021 hosts. Note that EID blocks MAY LISP RLOCs". 2023 o Indicate what address-family can appear in data packets. 2025 o ETRs may, rather than will, be the ones to send Map-Replies. 2027 o Recommend, rather than mandate, max encapsulation headers to 2. 2029 o Reference VPN draft when introducing Instance-ID. 2031 o Indicate that SMRs can be sent when ITR/ETR are in the same node. 2033 o Clarify when private addresses can be used. 2035 B.22. Changes to draft-ietf-lisp-rfc6830bis-05 2037 o Posted August 2017. 2039 o Make it clear that a Re-encapsulating Tunnel Router is an RTR. 2041 B.23. Changes to draft-ietf-lisp-rfc6830bis-04 2043 o Posted July 2017. 2045 o Changed reference of IPv6 RFC2460 to RFC8200. 2047 o Indicate that the applicability statement for UDP zero checksums 2048 over IPv6 adheres to RFC6936. 2050 B.24. Changes to draft-ietf-lisp-rfc6830bis-03 2052 o Posted May 2017. 2054 o Move the control-plane related codepoints in the IANA 2055 Considerations section to RFC6833bis. 2057 B.25. Changes to draft-ietf-lisp-rfc6830bis-02 2059 o Posted April 2017. 2061 o Reflect some editorial comments from Damien Sausez. 2063 B.26. Changes to draft-ietf-lisp-rfc6830bis-01 2065 o Posted March 2017. 2067 o Include references to new RFCs published. 2069 o Change references from RFC6833 to RFC6833bis. 2071 o Clarified LCAF text in the IANA section. 2073 o Remove references to "experimental". 2075 B.27. Changes to draft-ietf-lisp-rfc6830bis-00 2077 o Posted December 2016. 2079 o Created working group document from draft-farinacci-lisp 2080 -rfc6830-00 individual submission. No other changes made. 2082 Authors' Addresses 2084 Dino Farinacci 2085 Cisco Systems 2086 Tasman Drive 2087 San Jose, CA 95134 2088 USA 2090 EMail: farinacci@gmail.com 2092 Vince Fuller 2093 Cisco Systems 2094 Tasman Drive 2095 San Jose, CA 95134 2096 USA 2098 EMail: vince.fuller@gmail.com 2100 Dave Meyer 2101 Cisco Systems 2102 170 Tasman Drive 2103 San Jose, CA 2104 USA 2106 EMail: dmm@1-4-5.net 2108 Darrel Lewis 2109 Cisco Systems 2110 170 Tasman Drive 2111 San Jose, CA 2112 USA 2114 EMail: darlewis@cisco.com 2115 Albert Cabellos 2116 UPC/BarcelonaTech 2117 Campus Nord, C. Jordi Girona 1-3 2118 Barcelona, Catalunya 2119 Spain 2121 EMail: acabello@ac.upc.edu