idnits 2.17.1 draft-ietf-lisp-rfc6830bis-31.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 (March 5, 2020) is 1511 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 1753, but no explicit reference was found in the text == Unused Reference: 'RFC7835' is defined on line 1760, but no explicit reference was found in the text == Unused Reference: 'RFC8111' is defined on line 1778, but no explicit reference was found in the text == Outdated reference: A later version (-14) exists of draft-ietf-lisp-6834bis-06 == Outdated reference: A later version (-31) exists of draft-ietf-lisp-rfc6833bis-27 ** Obsolete normative reference: RFC 6830 (Obsoleted by RFC 9300, RFC 9301) ** Downref: Normative reference to an Experimental RFC: RFC 6831 ** Downref: Normative reference to an Experimental RFC: RFC 8378 == Outdated reference: A later version (-15) exists of draft-ietf-lisp-introduction-13 == Outdated reference: A later version (-12) exists of draft-ietf-lisp-vpn-05 Summary: 3 errors (**), 0 flaws (~~), 8 warnings (==), 1 comment (--).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 lispers.net 4 Obsoletes: 6830 (if approved) V. Fuller 5 Intended status: Standards Track vaf.net Internet Consulting 6 Expires: September 6, 2020 D. Meyer 7 1-4-5.net 8 D. Lewis 9 Cisco Systems 10 A. Cabellos (Ed.) 11 UPC/BarcelonaTech 12 March 5, 2020 14 The Locator/ID Separation Protocol (LISP) 15 draft-ietf-lisp-rfc6830bis-31 17 Abstract 19 This document describes the Data-Plane protocol for the Locator/ID 20 Separation Protocol (LISP). LISP defines two namespaces, End-point 21 Identifiers (EIDs) that identify end-hosts and Routing Locators 22 (RLOCs) that identify network attachment points. With this, LISP 23 effectively separates control from data, and allows routers to create 24 overlay networks. LISP-capable routers exchange encapsulated packets 25 according to EID-to-RLOC mappings stored in a local Map-Cache. 27 LISP requires no change to either host protocol stacks or to underlay 28 routers and offers Traffic Engineering, multihoming and mobility, 29 among other features. 31 This document obsoletes RFC 6830. 33 Status of This Memo 35 This Internet-Draft is submitted in full conformance with the 36 provisions of BCP 78 and BCP 79. 38 Internet-Drafts are working documents of the Internet Engineering 39 Task Force (IETF). Note that other groups may also distribute 40 working documents as Internet-Drafts. The list of current Internet- 41 Drafts is at https://datatracker.ietf.org/drafts/current/. 43 Internet-Drafts are draft documents valid for a maximum of six months 44 and may be updated, replaced, or obsoleted by other documents at any 45 time. It is inappropriate to use Internet-Drafts as reference 46 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on September 6, 2020. 50 Copyright Notice 52 Copyright (c) 2020 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents 57 (https://trustee.ietf.org/license-info) in effect on the date of 58 publication of this document. Please review these documents 59 carefully, as they describe your rights and restrictions with respect 60 to this document. Code Components extracted from this document must 61 include Simplified BSD License text as described in Section 4.e of 62 the Trust Legal Provisions and are provided without warranty as 63 described in the Simplified BSD License. 65 Table of Contents 67 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 68 1.1. Scope of Applicability . . . . . . . . . . . . . . . . . 4 69 2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 4 70 3. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 5 71 4. Basic Overview . . . . . . . . . . . . . . . . . . . . . . . 8 72 4.1. Packet Flow Sequence . . . . . . . . . . . . . . . . . . 10 73 5. LISP Encapsulation Details . . . . . . . . . . . . . . . . . 12 74 5.1. LISP IPv4-in-IPv4 Header Format . . . . . . . . . . . . . 13 75 5.2. LISP IPv6-in-IPv6 Header Format . . . . . . . . . . . . . 14 76 5.3. Tunnel Header Field Descriptions . . . . . . . . . . . . 15 77 6. LISP EID-to-RLOC Map-Cache . . . . . . . . . . . . . . . . . 19 78 7. Dealing with Large Encapsulated Packets . . . . . . . . . . . 20 79 7.1. A Stateless Solution to MTU Handling . . . . . . . . . . 20 80 7.2. A Stateful Solution to MTU Handling . . . . . . . . . . . 21 81 8. Using Virtualization and Segmentation with LISP . . . . . . . 22 82 9. Routing Locator Selection . . . . . . . . . . . . . . . . . . 22 83 10. Routing Locator Reachability . . . . . . . . . . . . . . . . 24 84 10.1. Echo Nonce Algorithm . . . . . . . . . . . . . . . . . . 26 85 11. EID Reachability within a LISP Site . . . . . . . . . . . . . 27 86 12. Routing Locator Hashing . . . . . . . . . . . . . . . . . . . 27 87 13. Changing the Contents of EID-to-RLOC Mappings . . . . . . . . 28 88 13.1. Locator-Status-Bits . . . . . . . . . . . . . . . . . . 29 89 13.2. Database Map-Versioning . . . . . . . . . . . . . . . . 29 90 14. Multicast Considerations . . . . . . . . . . . . . . . . . . 30 91 15. Router Performance Considerations . . . . . . . . . . . . . . 31 92 16. Security Considerations . . . . . . . . . . . . . . . . . . . 32 93 17. Network Management Considerations . . . . . . . . . . . . . . 33 94 18. Changes since RFC 6830 . . . . . . . . . . . . . . . . . . . 33 95 19. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34 96 19.1. LISP UDP Port Numbers . . . . . . . . . . . . . . . . . 34 97 20. References . . . . . . . . . . . . . . . . . . . . . . . . . 34 98 20.1. Normative References . . . . . . . . . . . . . . . . . . 34 99 20.2. Informative References . . . . . . . . . . . . . . . . . 36 100 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 39 101 Appendix B. Document Change Log . . . . . . . . . . . . . . . . 40 102 B.1. Changes to draft-ietf-lisp-rfc6830bis-27 . . . . . . . . 40 103 B.2. Changes to draft-ietf-lisp-rfc6830bis-27 . . . . . . . . 40 104 B.3. Changes to draft-ietf-lisp-rfc6830bis-26 . . . . . . . . 40 105 B.4. Changes to draft-ietf-lisp-rfc6830bis-25 . . . . . . . . 41 106 B.5. Changes to draft-ietf-lisp-rfc6830bis-24 . . . . . . . . 41 107 B.6. Changes to draft-ietf-lisp-rfc6830bis-23 . . . . . . . . 41 108 B.7. Changes to draft-ietf-lisp-rfc6830bis-22 . . . . . . . . 41 109 B.8. Changes to draft-ietf-lisp-rfc6830bis-21 . . . . . . . . 41 110 B.9. Changes to draft-ietf-lisp-rfc6830bis-20 . . . . . . . . 41 111 B.10. Changes to draft-ietf-lisp-rfc6830bis-19 . . . . . . . . 41 112 B.11. Changes to draft-ietf-lisp-rfc6830bis-18 . . . . . . . . 42 113 B.12. Changes to draft-ietf-lisp-rfc6830bis-17 . . . . . . . . 42 114 B.13. Changes to draft-ietf-lisp-rfc6830bis-16 . . . . . . . . 42 115 B.14. Changes to draft-ietf-lisp-rfc6830bis-15 . . . . . . . . 42 116 B.15. Changes to draft-ietf-lisp-rfc6830bis-14 . . . . . . . . 42 117 B.16. Changes to draft-ietf-lisp-rfc6830bis-13 . . . . . . . . 42 118 B.17. Changes to draft-ietf-lisp-rfc6830bis-12 . . . . . . . . 43 119 B.18. Changes to draft-ietf-lisp-rfc6830bis-11 . . . . . . . . 43 120 B.19. Changes to draft-ietf-lisp-rfc6830bis-10 . . . . . . . . 43 121 B.20. Changes to draft-ietf-lisp-rfc6830bis-09 . . . . . . . . 43 122 B.21. Changes to draft-ietf-lisp-rfc6830bis-08 . . . . . . . . 44 123 B.22. Changes to draft-ietf-lisp-rfc6830bis-07 . . . . . . . . 44 124 B.23. Changes to draft-ietf-lisp-rfc6830bis-06 . . . . . . . . 44 125 B.24. Changes to draft-ietf-lisp-rfc6830bis-05 . . . . . . . . 44 126 B.25. Changes to draft-ietf-lisp-rfc6830bis-04 . . . . . . . . 45 127 B.26. Changes to draft-ietf-lisp-rfc6830bis-03 . . . . . . . . 45 128 B.27. Changes to draft-ietf-lisp-rfc6830bis-02 . . . . . . . . 45 129 B.28. Changes to draft-ietf-lisp-rfc6830bis-01 . . . . . . . . 45 130 B.29. Changes to draft-ietf-lisp-rfc6830bis-00 . . . . . . . . 45 131 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 45 133 1. Introduction 135 This document describes the Locator/Identifier Separation Protocol 136 (LISP). LISP is an encapsulation protocol built around the 137 fundamental idea of separating the topological location of a network 138 attachment point from the node's identity [CHIAPPA]. As a result 139 LISP creates two namespaces: Endpoint Identifiers (EIDs), that are 140 used to identify end-hosts (e.g., nodes or Virtual Machines) and 141 routable Routing Locators (RLOCs), used to identify network 142 attachment points. LISP then defines functions for mapping between 143 the two namespaces and for encapsulating traffic originated by 144 devices using non-routable EIDs for transport across a network 145 infrastructure that routes and forwards using RLOCs. LISP 146 encapsulation uses a dynamic form of tunneling where no static 147 provisioning is required or necessary. 149 LISP is an overlay protocol that separates control from Data-Plane, 150 this document specifies the Data-Plane as well as how LISP-capable 151 routers (Tunnel Routers) exchange packets by encapsulating them to 152 the appropriate location. Tunnel routers are equipped with a cache, 153 called Map-Cache, that contains EID-to-RLOC mappings. The Map-Cache 154 is populated using the LISP Control-Plane protocol 155 [I-D.ietf-lisp-rfc6833bis]. 157 LISP does not require changes to either the host protocol stack or to 158 underlay routers. By separating the EID from the RLOC space, LISP 159 offers native Traffic Engineering, multihoming and mobility, among 160 other features. 162 Creation of LISP was initially motivated by discussions during the 163 IAB-sponsored Routing and Addressing Workshop held in Amsterdam in 164 October 2006 (see [RFC4984]). 166 This document specifies the LISP Data-Plane encapsulation and other 167 LISP forwarding node functionality while [I-D.ietf-lisp-rfc6833bis] 168 specifies the LISP control plane. LISP deployment guidelines can be 169 found in [RFC7215] and [RFC6835] describes considerations for network 170 operational management. Finally, [I-D.ietf-lisp-introduction] 171 describes the LISP architecture. 173 This document obsoletes RFC 6830. 175 1.1. Scope of Applicability 177 LISP was originally developed to address the Internet-wide route 178 scaling problem [RFC4984]. While there are a number of approaches of 179 interest for that problem, as LISP as been developed and refined, a 180 large number of other LISP uses have been found and are being used. 181 As such, the design and development of LISP has changed so as to 182 focus on these use cases. The common property of these uses is a 183 large set of cooperating entities seeking to communicate over the 184 public Internet or other large underlay IP infrastructures, while 185 keeping the addressing and topology of the cooperating entities 186 separate from the underlay and Internet topology, routing, and 187 addressing. 189 2. Requirements Notation 191 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 192 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 193 "OPTIONAL" in this document are to be interpreted as described in BCP 194 14 [RFC2119] [RFC8174] when, and only when, they appear in all 195 capitals, as shown here. 197 3. Definition of Terms 199 Address Family Identifier (AFI): AFI is a term used to describe an 200 address encoding in a packet. An address family that pertains to 201 addresses found in Data-Plane headers. See [AFN] and [RFC3232] 202 for details. An AFI value of 0 used in this specification 203 indicates an unspecified encoded address where the length of the 204 address is 0 octets following the 16-bit AFI value of 0. 206 Anycast Address: Anycast Address refers to the same IPv4 or IPv6 207 address configured and used on multiple systems at the same time. 208 An EID or RLOC can be an anycast address in each of their own 209 address spaces. 211 Client-side: Client-side is a term used in this document to indicate 212 a connection initiation attempt by an end-system represented by an 213 EID. 215 Egress Tunnel Router (ETR): An ETR is a router that accepts an IP 216 packet where the destination address in the "outer" IP header is 217 one of its own RLOCs. The router strips the "outer" header and 218 forwards the packet based on the next IP header found. In 219 general, an ETR receives LISP-encapsulated IP packets from the 220 Internet on one side and sends decapsulated IP packets to site 221 end-systems on the other side. ETR functionality does not have to 222 be limited to a router device. A server host can be the endpoint 223 of a LISP tunnel as well. 225 EID-to-RLOC Database: The EID-to-RLOC Database is a distributed 226 database that contains all known EID-Prefix-to-RLOC mappings. 227 Each potential ETR typically contains a small piece of the 228 database: the EID-to-RLOC mappings for the EID-Prefixes "behind" 229 the router. These map to one of the router's own IP addresses 230 that are routable on the underlay. Note that there MAY be 231 transient conditions when the EID-Prefix for the LISP site and 232 Locator-Set for each EID-Prefix may not be the same on all ETRs. 233 This has no negative implications, since a partial set of Locators 234 can be used. 236 EID-to-RLOC Map-Cache: The EID-to-RLOC Map-Cache is generally 237 short-lived, on-demand table in an ITR that stores, tracks, and is 238 responsible for timing out and otherwise validating EID-to-RLOC 239 mappings. This cache is distinct from the full "database" of EID- 240 to-RLOC mappings; it is dynamic, local to the ITR(s), and 241 relatively small, while the database is distributed, relatively 242 static, and much more widely scoped to LISP nodes. 244 EID-Prefix: An EID-Prefix is a power-of-two block of EIDs that are 245 allocated to a site by an address allocation authority. EID- 246 Prefixes are associated with a set of RLOC addresses. EID-Prefix 247 allocations can be broken up into smaller blocks when an RLOC set 248 is to be associated with the larger EID-Prefix block. 250 End-System: An end-system is an IPv4 or IPv6 device that originates 251 packets with a single IPv4 or IPv6 header. The end-system 252 supplies an EID value for the destination address field of the IP 253 header when communicating outside of its routing domain. An end- 254 system can be a host computer, a switch or router device, or any 255 network appliance. 257 Endpoint ID (EID): An EID is a 32-bit (for IPv4) or 128-bit (for 258 IPv6) value that identifies a host. EIDs are generally only found 259 in the source and destination address fields of the first (most 260 inner) LISP header of a packet. The host obtains a destination 261 EID the same way it obtains a destination address today, for 262 example, through a Domain Name System (DNS) [RFC1034] lookup or 263 Session Initiation Protocol (SIP) [RFC3261] exchange. The source 264 EID is obtained via existing mechanisms used to set a host's 265 "local" IP address. An EID used on the public Internet MUST have 266 the same properties as any other IP address used in that manner; 267 this means, among other things, that it MUST be unique. An EID is 268 allocated to a host from an EID-Prefix block associated with the 269 site where the host is located. An EID can be used by a host to 270 refer to other hosts. Note that EID blocks MAY be assigned in a 271 hierarchical manner, independent of the network topology, to 272 facilitate scaling of the mapping database. In addition, an EID 273 block assigned to a site MAY have site-local structure 274 (subnetting) for routing within the site; this structure is not 275 visible to the underlay routing system. In theory, the bit string 276 that represents an EID for one device can represent an RLOC for a 277 different device. When used in discussions with other Locator/ID 278 separation proposals, a LISP EID will be called an "LEID". 279 Throughout this document, any references to "EID" refer to an 280 LEID. 282 Ingress Tunnel Router (ITR): An ITR is a router that resides in a 283 LISP site. Packets sent by sources inside of the LISP site to 284 destinations outside of the site are candidates for encapsulation 285 by the ITR. The ITR treats the IP destination address as an EID 286 and performs an EID-to-RLOC mapping lookup. The router then 287 prepends an "outer" IP header with one of its routable RLOCs (in 288 the RLOC space) in the source address field and the result of the 289 mapping lookup in the destination address field. Note that this 290 destination RLOC may be an intermediate, proxy device that has 291 better knowledge of the EID-to-RLOC mapping closer to the 292 destination EID. In general, an ITR receives IP packets from site 293 end-systems on one side and sends LISP-encapsulated IP packets 294 toward the Internet on the other side. 296 LISP Header: LISP header is a term used in this document to refer 297 to the outer IPv4 or IPv6 header, a UDP header, and a LISP- 298 specific 8-octet header that follow the UDP header and that an ITR 299 prepends or an ETR strips. 301 LISP Router: A LISP router is a router that performs the functions 302 of any or all of the following: ITR, ETR, RTR, Proxy-ITR (PITR), 303 or Proxy-ETR (PETR). 305 LISP Site: LISP site is a set of routers in an edge network that are 306 under a single technical administration. LISP routers that reside 307 in the edge network are the demarcation points to separate the 308 edge network from the core network. 310 Locator-Status-Bits (LSBs): Locator-Status-Bits are present in the 311 LISP header. They are used by ITRs to inform ETRs about the up/ 312 down status of all ETRs at the local site. These bits are used as 313 a hint to convey up/down router status and not path reachability 314 status. The LSBs can be verified by use of one of the Locator 315 reachability algorithms described in Section 10. An ETR MUST 316 rate-limit the action it takes when it detects changes in the 317 Locator-Status-Bits. 319 Proxy-ETR (PETR): A PETR is defined and described in [RFC6832]. A 320 PETR acts like an ETR but does so on behalf of LISP sites that 321 send packets to destinations at non-LISP sites. 323 Proxy-ITR (PITR): A PITR is defined and described in [RFC6832]. A 324 PITR acts like an ITR but does so on behalf of non-LISP sites that 325 send packets to destinations at LISP sites. 327 Recursive Tunneling: Recursive Tunneling occurs when a packet has 328 more than one LISP IP header. Additional layers of tunneling MAY 329 be employed to implement Traffic Engineering or other re-routing 330 as needed. When this is done, an additional "outer" LISP header 331 is added, and the original RLOCs are preserved in the "inner" 332 header. 334 Re-Encapsulating Tunneling Router (RTR): An RTR acts like an ETR to 335 remove a LISP header, then acts as an ITR to prepend a new LISP 336 header. This is known as Re-encapsulating Tunneling. Doing this 337 allows a packet to be re-routed by the RTR without adding the 338 overhead of additional tunnel headers. When using multiple 339 mapping database systems, care must be taken to not create re- 340 encapsulation loops through misconfiguration. 342 Route-Returnability: Route-returnability is an assumption that the 343 underlying routing system will deliver packets to the destination. 344 When combined with a nonce that is provided by a sender and 345 returned by a receiver, this limits off-path data insertion. A 346 route-returnability check is verified when a message is sent with 347 a nonce, another message is returned with the same nonce, and the 348 destination of the original message appears as the source of the 349 returned message. 351 Routing Locator (RLOC): An RLOC is an IPv4 [RFC0791] or IPv6 352 [RFC8200] address of an Egress Tunnel Router (ETR). An RLOC is 353 the output of an EID-to-RLOC mapping lookup. An EID maps to zero 354 or more RLOCs. Typically, RLOCs are numbered from blocks that are 355 assigned to a site at each point to which it attaches to the 356 underlay network; where the topology is defined by the 357 connectivity of provider networks. Multiple RLOCs can be assigned 358 to the same ETR device or to multiple ETR devices at a site. 360 Server-side: Server-side is a term used in this document to indicate 361 that a connection initiation attempt is being accepted for a 362 destination EID. 364 xTR: An xTR is a reference to an ITR or ETR when direction of data 365 flow is not part of the context description. "xTR" refers to the 366 router that is the tunnel endpoint and is used synonymously with 367 the term "Tunnel Router". For example, "An xTR can be located at 368 the Customer Edge (CE) router" indicates both ITR and ETR 369 functionality at the CE router. 371 4. Basic Overview 373 One key concept of LISP is that end-systems operate the same way they 374 do today. The IP addresses that hosts use for tracking sockets and 375 connections, and for sending and receiving packets, do not change. 376 In LISP terminology, these IP addresses are called Endpoint 377 Identifiers (EIDs). 379 Routers continue to forward packets based on IP destination 380 addresses. When a packet is LISP encapsulated, these addresses are 381 referred to as Routing Locators (RLOCs). Most routers along a path 382 between two hosts will not change; they continue to perform routing/ 383 forwarding lookups on the destination addresses. For routers between 384 the source host and the ITR as well as routers from the ETR to the 385 destination host, the destination address is an EID. For the routers 386 between the ITR and the ETR, the destination address is an RLOC. 388 Another key LISP concept is the "Tunnel Router". A Tunnel Router 389 prepends LISP headers on host-originated packets and strips them 390 prior to final delivery to their destination. The IP addresses in 391 this "outer header" are RLOCs. During end-to-end packet exchange 392 between two Internet hosts, an ITR prepends a new LISP header to each 393 packet, and an ETR strips the new header. The ITR performs EID-to- 394 RLOC lookups to determine the routing path to the ETR, which has the 395 RLOC as one of its IP addresses. 397 Some basic rules governing LISP are: 399 o End-systems only send to addresses that are EIDs. EIDs are 400 typically IP addresses assigned to hosts (other types of EID are 401 supported by LISP, see [RFC8060] for further information). End- 402 systems don't know that addresses are EIDs versus RLOCs but assume 403 that packets get to their intended destinations. In a system 404 where LISP is deployed, LISP routers intercept EID-addressed 405 packets and assist in delivering them across the network core 406 where EIDs cannot be routed. The procedure a host uses to send IP 407 packets does not change. 409 o LISP routers mostly deal with Routing Locator addresses. See 410 details in Section 4.1 to clarify what is meant by "mostly". 412 o RLOCs are always IP addresses assigned to routers, preferably 413 topologically oriented addresses from provider CIDR (Classless 414 Inter-Domain Routing) blocks. 416 o When a router originates packets, it MAY use as a source address 417 either an EID or RLOC. When acting as a host (e.g., when 418 terminating a transport session such as Secure SHell (SSH), 419 TELNET, or the Simple Network Management Protocol (SNMP)), it MAY 420 use an EID that is explicitly assigned for that purpose. An EID 421 that identifies the router as a host MUST NOT be used as an RLOC; 422 an EID is only routable within the scope of a site. A typical BGP 423 configuration might demonstrate this "hybrid" EID/RLOC usage where 424 a router could use its "host-like" EID to terminate iBGP sessions 425 to other routers in a site while at the same time using RLOCs to 426 terminate eBGP sessions to routers outside the site. 428 o Packets with EIDs in them are not expected to be delivered end-to- 429 end in the absence of an EID-to-RLOC mapping operation. They are 430 expected to be used locally for intra-site communication or to be 431 encapsulated for inter-site communication. 433 o EIDs MAY also be structured (subnetted) in a manner suitable for 434 local routing within an Autonomous System (AS). 436 An additional LISP header MAY be prepended to packets by a TE-ITR 437 when re-routing of the path for a packet is desired. A potential 438 use-case for this would be an ISP router that needs to perform 439 Traffic Engineering for packets flowing through its network. In such 440 a situation, termed "Recursive Tunneling", an ISP transit acts as an 441 additional ITR, and the destination RLOC it uses for the new 442 prepended header would be either a TE-ETR within the ISP (along an 443 intra-ISP traffic engineered path) or a TE-ETR within another ISP (an 444 inter-ISP traffic engineered path, where an agreement to build such a 445 path exists). 447 In order to avoid excessive packet overhead as well as possible 448 encapsulation loops, this document recommends that a maximum of two 449 LISP headers can be prepended to a packet. For initial LISP 450 deployments, it is assumed that two headers is sufficient, where the 451 first prepended header is used at a site for Location/Identity 452 separation and the second prepended header is used inside a service 453 provider for Traffic Engineering purposes. 455 Tunnel Routers can be placed fairly flexibly in a multi-AS topology. 456 For example, the ITR for a particular end-to-end packet exchange 457 might be the first-hop or default router within a site for the source 458 host. Similarly, the ETR might be the last-hop router directly 459 connected to the destination host. Another example, perhaps for a 460 VPN service outsourced to an ISP by a site, the ITR could be the 461 site's border router at the service provider attachment point. 462 Mixing and matching of site-operated, ISP-operated, and other Tunnel 463 Routers is allowed for maximum flexibility. 465 4.1. Packet Flow Sequence 467 This section provides an example of the unicast packet flow, 468 including also Control-Plane information as specified in 469 [I-D.ietf-lisp-rfc6833bis]. The example also assumes the following 470 conditions: 472 o Source host "host1.abc.example.com" is sending a packet to 473 "host2.xyz.example.com", exactly what host1 would do if the site 474 was not using LISP. 476 o Each site is multihomed, so each Tunnel Router has an address 477 (RLOC) assigned from the service provider address block for each 478 provider to which that particular Tunnel Router is attached. 480 o The ITR(s) and ETR(s) are directly connected to the source and 481 destination, respectively, but the source and destination can be 482 located anywhere in the LISP site. 484 o A Map-Request is sent for an external destination when the 485 destination is not found in the forwarding table or matches a 486 default route. Map-Requests are sent to the mapping database 487 system by using the LISP Control-Plane protocol documented in 488 [I-D.ietf-lisp-rfc6833bis]. 490 o Map-Replies are sent on the underlying routing system topology 491 using the [I-D.ietf-lisp-rfc6833bis] Control-Plane protocol. 493 Client host1.abc.example.com wants to communicate with server 494 host2.xyz.example.com: 496 1. host1.abc.example.com wants to open a TCP connection to 497 host2.xyz.example.com. It does a DNS lookup on 498 host2.xyz.example.com. An A/AAAA record is returned. This 499 address is the destination EID. The locally assigned address of 500 host1.abc.example.com is used as the source EID. An IPv4 or IPv6 501 packet is built and forwarded through the LISP site as a normal 502 IP packet until it reaches a LISP ITR. 504 2. The LISP ITR must be able to map the destination EID to an RLOC 505 of one of the ETRs at the destination site. A method to do this 506 is to send a LISP Map-Request, as specified in 507 [I-D.ietf-lisp-rfc6833bis]. 509 3. The mapping system helps forwarding the Map-Request to the 510 corresponding ETR. When the Map-Request arrives at one of the 511 ETRs at the destination site, it will process the packet as a 512 control message. 514 4. The ETR looks at the destination EID of the Map-Request and 515 matches it against the prefixes in the ETR's configured EID-to- 516 RLOC mapping database. This is the list of EID-Prefixes the ETR 517 is supporting for the site it resides in. If there is no match, 518 the Map-Request is dropped. Otherwise, a LISP Map-Reply is 519 returned to the ITR. 521 5. The ITR receives the Map-Reply message, parses the message, and 522 stores the mapping information from the packet. This information 523 is stored in the ITR's EID-to-RLOC Map-Cache. Note that the Map- 524 Cache is an on-demand cache. An ITR will manage its Map-Cache in 525 such a way that optimizes for its resource constraints. 527 6. Subsequent packets from host1.abc.example.com to 528 host2.xyz.example.com will have a LISP header prepended by the 529 ITR using the appropriate RLOC as the LISP header destination 530 address learned from the ETR. Note that the packet MAY be sent 531 to a different ETR than the one that returned the Map-Reply due 532 to the source site's hashing policy or the destination site's 533 Locator-Set policy. 535 7. The ETR receives these packets directly (since the destination 536 address is one of its assigned IP addresses), checks the validity 537 of the addresses, strips the LISP header, and forwards packets to 538 the attached destination host. 540 8. In order to defer the need for a mapping lookup in the reverse 541 direction, an ETR can OPTIONALLY create a cache entry that maps 542 the source EID (inner-header source IP address) to the source 543 RLOC (outer-header source IP address) in a received LISP packet. 544 Such a cache entry is termed a "glean mapping" and only contains 545 a single RLOC for the EID in question. More complete information 546 about additional RLOCs SHOULD be verified by sending a LISP Map- 547 Request for that EID. Both the ITR and the ETR MAY also 548 influence the decision the other makes in selecting an RLOC. 550 5. LISP Encapsulation Details 552 Since additional tunnel headers are prepended, the packet becomes 553 larger and can exceed the MTU of any link traversed from the ITR to 554 the ETR. It is RECOMMENDED in IPv4 that packets do not get 555 fragmented as they are encapsulated by the ITR. Instead, the packet 556 is dropped and an ICMP Unreachable/Fragmentation-Needed message is 557 returned to the source. 559 In the case when fragmentation is needed, this specification 560 RECOMMENDS that implementations provide support for one of the 561 proposed fragmentation and reassembly schemes. Two existing schemes 562 are detailed in Section 7. 564 Since IPv4 or IPv6 addresses can be either EIDs or RLOCs, the LISP 565 architecture supports IPv4 EIDs with IPv6 RLOCs (where the inner 566 header is in IPv4 packet format and the outer header is in IPv6 567 packet format) or IPv6 EIDs with IPv4 RLOCs (where the inner header 568 is in IPv6 packet format and the outer header is in IPv4 packet 569 format). The next sub-sections illustrate packet formats for the 570 homogeneous case (IPv4-in-IPv4 and IPv6-in-IPv6), but all 4 571 combinations MUST be supported. Additional types of EIDs are defined 572 in [RFC8060]. 574 As LISP uses UDP encapsulation to carry traffic between xTRs across 575 the Internet, implementors should be aware of the provisions of 576 [RFC8085], especially those given in section 3.1.11 on congestion 577 control for UDP tunneling. 579 Implementors are encouraged to consider UDP checksum usage guidelines 580 in section 3.4 of [RFC8085] when it is desirable to protect UDP and 581 LISP headers against corruption. 583 5.1. LISP IPv4-in-IPv4 Header Format 585 0 1 2 3 586 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 1 587 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 588 / |Version| IHL | DSCP |ECN| Total Length | 589 / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 590 | | Identification |Flags| Fragment Offset | 591 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 592 OH | Time to Live | Protocol = 17 | Header Checksum | 593 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 594 | | Source Routing Locator | 595 \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 596 \ | Destination Routing Locator | 597 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 598 / | Source Port = xxxx | Dest Port = 4341 | 599 UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 600 \ | UDP Length | UDP Checksum | 601 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 602 L |N|L|E|V|I|R|K|K| Nonce/Map-Version | 603 I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 604 S / | Instance ID/Locator-Status-Bits | 605 P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 606 / |Version| IHL | DSCP |ECN| Total Length | 607 / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 608 | | Identification |Flags| Fragment Offset | 609 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 610 IH | Time to Live | Protocol | Header Checksum | 611 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 612 | | Source EID | 613 \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 614 \ | Destination EID | 615 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 617 IHL = IP-Header-Length 619 5.2. LISP IPv6-in-IPv6 Header Format 621 0 1 2 3 622 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 1 623 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 624 / |Version| DSCP |ECN| Flow Label | 625 / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 626 | | Payload Length | Next Header=17| Hop Limit | 627 v +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 628 | | 629 O + + 630 u | | 631 t + Source Routing Locator + 632 e | | 633 r + + 634 | | 635 H +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 636 d | | 637 r + + 638 | | 639 ^ + Destination Routing Locator + 640 | | | 641 \ + + 642 \ | | 643 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 644 / | Source Port = xxxx | Dest Port = 4341 | 645 UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 646 \ | UDP Length | UDP Checksum | 647 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 648 L |N|L|E|V|I|R|K|K| Nonce/Map-Version | 649 I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 650 S / | Instance ID/Locator-Status-Bits | 651 P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 652 / |Version| DSCP |ECN| Flow Label | 653 / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 654 / | Payload Length | Next Header | Hop Limit | 655 v +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 656 | | 657 I + + 658 n | | 659 n + Source EID + 660 e | | 661 r + + 662 | | 663 H +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 664 d | | 665 r + + 666 | | 668 ^ + Destination EID + 669 \ | | 670 \ + + 671 \ | | 672 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 674 5.3. Tunnel Header Field Descriptions 676 Inner Header (IH): The inner header is the header on the 677 datagram received from the originating host [RFC0791] [RFC8200] 678 [RFC2474]. The source and destination IP addresses are EIDs. 680 Outer Header: (OH) The outer header is a new header prepended by an 681 ITR. The address fields contain RLOCs obtained from the ingress 682 router's EID-to-RLOC Cache. The IP protocol number is "UDP (17)" 683 from [RFC0768]. The setting of the Don't Fragment (DF) bit 684 'Flags' field is according to rules listed in Sections 7.1 and 685 7.2. 687 UDP Header: The UDP header contains an ITR selected source port when 688 encapsulating a packet. See Section 12 for details on the hash 689 algorithm used to select a source port based on the 5-tuple of the 690 inner header. The destination port MUST be set to the well-known 691 IANA-assigned port value 4341. 693 UDP Checksum: The 'UDP Checksum' field SHOULD be transmitted as zero 694 by an ITR for either IPv4 [RFC0768] and IPv6 encapsulation 695 [RFC6935] [RFC6936]. When a packet with a zero UDP checksum is 696 received by an ETR, the ETR MUST accept the packet for 697 decapsulation. When an ITR transmits a non-zero value for the UDP 698 checksum, it MUST send a correctly computed value in this field. 699 When an ETR receives a packet with a non-zero UDP checksum, it MAY 700 choose to verify the checksum value. If it chooses to perform 701 such verification, and the verification fails, the packet MUST be 702 silently dropped. If the ETR chooses not to perform the 703 verification, or performs the verification successfully, the 704 packet MUST be accepted for decapsulation. The handling of UDP 705 zero checksums over IPv6 for all tunneling protocols, including 706 LISP, is subject to the applicability statement in [RFC6936]. 708 UDP Length: The 'UDP Length' field is set for an IPv4-encapsulated 709 packet to be the sum of the inner-header IPv4 Total Length plus 710 the UDP and LISP header lengths. For an IPv6-encapsulated packet, 711 the 'UDP Length' field is the sum of the inner-header IPv6 Payload 712 Length, the size of the IPv6 header (40 octets), and the size of 713 the UDP and LISP headers. 715 N: The N-bit is the nonce-present bit. When this bit is set to 1, 716 the low-order 24 bits of the first 32 bits of the LISP header 717 contain a Nonce. See Section 10.1 for details. Both N- and 718 V-bits MUST NOT be set in the same packet. If they are, a 719 decapsulating ETR MUST treat the 'Nonce/Map-Version' field as 720 having a Nonce value present. 722 L: The L-bit is the 'Locator-Status-Bits' field enabled bit. When 723 this bit is set to 1, the Locator-Status-Bits in the second 724 32 bits of the LISP header are in use. 726 x 1 x x 0 x x x 727 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 728 |N|L|E|V|I|R|K|K| Nonce/Map-Version | 729 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 730 | Locator-Status-Bits | 731 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 733 E: The E-bit is the echo-nonce-request bit. This bit MUST be ignored 734 and has no meaning when the N-bit is set to 0. When the N-bit is 735 set to 1 and this bit is set to 1, an ITR is requesting that the 736 nonce value in the 'Nonce' field be echoed back in LISP- 737 encapsulated packets when the ITR is also an ETR. See 738 Section 10.1 for details. 740 V: The V-bit is the Map-Version present bit. When this bit is set to 741 1, the N-bit MUST be 0. Refer to Section 13.2 for more details. 742 This bit indicates that the LISP header is encoded in this 743 case as: 745 0 x 0 1 x x x x 746 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 747 |N|L|E|V|I|R|K|K| Source Map-Version | Dest Map-Version | 748 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 749 | Instance ID/Locator-Status-Bits | 750 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 752 I: The I-bit is the Instance ID bit. See Section 8 for more details. 753 When this bit is set to 1, the 'Locator-Status-Bits' field is 754 reduced to 8 bits and the high-order 24 bits are used as an 755 Instance ID. If the L-bit is set to 0, then the low-order 8 bits 756 are transmitted as zero and ignored on receipt. The format of the 757 LISP header would look like this: 759 x x x x 1 x x x 760 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 761 |N|L|E|V|I|R|K|K| Nonce/Map-Version | 762 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 763 | Instance ID | LSBs | 764 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 766 R: The R-bit is a Reserved and unassigned bit for future use. It 767 MUST be set to 0 on transmit and MUST be ignored on receipt. 769 KK: The KK-bits are a 2-bit field used when encapsulated packets are 770 encrypted. The field is set to 00 when the packet is not 771 encrypted. See [RFC8061] for further information. 773 LISP Nonce: The LISP 'Nonce' field is a 24-bit value that is 774 randomly generated by an ITR when the N-bit is set to 1. Nonce 775 generation algorithms are an implementation matter but are 776 required to generate different nonces when sending to different 777 RLOCs. However, the same nonce can be used for a period of time 778 when encapsulating to the same ETR. The nonce is also used when 779 the E-bit is set to request the nonce value to be echoed by the 780 other side when packets are returned. When the E-bit is clear but 781 the N-bit is set, a remote ITR is either echoing a previously 782 requested echo-nonce or providing a random nonce. See 783 Section 10.1 for more details. 785 LISP Locator-Status-Bits (LSBs): When the L-bit is also set, the 786 'Locator-Status-Bits' field in the LISP header is set by an ITR to 787 indicate to an ETR the up/down status of the Locators in the 788 source site. Each RLOC in a Map-Reply is assigned an ordinal 789 value from 0 to n-1 (when there are n RLOCs in a mapping entry). 790 The Locator-Status-Bits are numbered from 0 to n-1 from the least 791 significant bit of the field. The field is 32 bits when the I-bit 792 is set to 0 and is 8 bits when the I-bit is set to 1. When a 793 Locator-Status-Bit is set to 1, the ITR is indicating to the ETR 794 that the RLOC associated with the bit ordinal has up status. See 795 Section 10 for details on how an ITR can determine the status of 796 the ETRs at the same site. When a site has multiple EID-Prefixes 797 that result in multiple mappings (where each could have a 798 different Locator-Set), the Locator-Status-Bits setting in an 799 encapsulated packet MUST reflect the mapping for the EID-Prefix 800 that the inner-header source EID address matches (longest-match). 801 If the LSB for an anycast Locator is set to 1, then there is at 802 least one RLOC with that address, and the ETR is considered 'up'. 804 When doing ITR/PITR encapsulation: 806 o The outer-header 'Time to Live' field (or 'Hop Limit' field, in 807 the case of IPv6) SHOULD be copied from the inner-header 'Time to 808 Live' field. 810 o The outer-header IPv4 'Differentiated Services Code Point' (DSCP) 811 field or the 'Traffic Class' field, in the case of IPv6, SHOULD be 812 copied from the inner-header IPv4 DSCP field or 'Traffic Class' 813 field in the case of IPv6, to the outer-header. 815 o The IPv4 'Explicit Congestion Notification' (ECN) field and bits 6 816 and 7 of the IPv6 'Traffic Class' field requires special treatment 817 in order to avoid discarding indications of congestion as 818 specified in [RFC6040]. 820 When doing ETR/PETR decapsulation: 822 o The inner-header IPv4 'Time to Live' field or 'Hop Limit' field in 823 the case of IPv6, MUST be copied from the outer-header 'Time to 824 Live'/'Hop Limit' field, when the 'Time to Live'/'Hop Limit' value 825 of the outer header is less than the 'Time to Live'/'Hop Limit' 826 value of the inner header. Failing to perform this check can 827 cause the 'Time to Live'/'Hop Limit' of the inner header to 828 increment across encapsulation/decapsulation cycles. This check 829 is also performed when doing initial encapsulation, when a packet 830 comes to an ITR or PITR destined for a LISP site. 832 o The outer-header IPv4 'Differentiated Services Code Point' (DSCP) 833 field or the 'Traffic Class' field in the case of IPv6, SHOULD be 834 copied from the outer-header IPv4 DSCP field or 'Traffic Class' 835 field in the case of IPv6, to the inner-header. 837 o The IPv4 'Explicit Congestion Notification' (ECN) field and bits 6 838 and 7 of the IPv6 'Traffic Class' field, requires special 839 treatment in order to avoid discarding indications of congestion 840 as specified in [RFC6040]. Note that implementations exist that 841 copy the 'ECN' field from the outer header to the inner header 842 even though [RFC6040] does not recommend this behavior. It is 843 RECOMMENDED that implementations change to support the behavior in 844 [RFC6040]. 846 Note that if an ETR/PETR is also an ITR/PITR and chooses to re- 847 encapsulate after decapsulating, the net effect of this is that the 848 new outer header will carry the same Time to Live as the old outer 849 header minus 1. 851 Copying the Time to Live (TTL) serves two purposes: first, it 852 preserves the distance the host intended the packet to travel; 853 second, and more importantly, it provides for suppression of looping 854 packets in the event there is a loop of concatenated tunnels due to 855 misconfiguration. 857 Some xTRs and PxTRs performs re-encapsulation operations and need to 858 treat the 'Explicit Congestion Notification' (ECN) in a special way. 859 Because the re-encapsulation operation is a sequence of two 860 operations, namely a decapsulation followed by an encapsulation, the 861 ECN bits MUST be treated as described above for these two operations. 863 The LISP dataplane protocol is not backwards compatible with 864 [RFC6830] and does not have explicit support for introducing future 865 protocol changes (e.g. an explicit version field), However, the LISP 866 control plane [I-D.ietf-lisp-rfc6833bis] allows an ETR to register 867 dataplane capabilities by means of new LCAF types [RFC8060]. In this 868 way an ITR can be made aware of the dataplane capabilities of an ETR, 869 and encapsulate accordingly. The specification of the new LCAF 870 types, new LCAF mechanisms, and their use, is out of the scope of 871 this document. 873 6. LISP EID-to-RLOC Map-Cache 875 ITRs and PITRs maintain an on-demand cache, referred as LISP EID-to- 876 RLOC Map-Cache, that contains mappings from EID-prefixes to locator 877 sets. The cache is used to encapsulate packets from the EID space to 878 the corresponding RLOC network attachment point. 880 When an ITR/PITR receives a packet from inside of the LISP site to 881 destinations outside of the site a longest-prefix match lookup of the 882 EID is done to the Map-Cache. 884 When the lookup succeeds, the Locator-Set retrieved from the Map- 885 Cache is used to send the packet to the EID's topological location. 887 If the lookup fails, the ITR/PITR needs to retrieve the mapping using 888 the LISP Control-Plane protocol [I-D.ietf-lisp-rfc6833bis]. While 889 the mapping is being retrieved, the ITR/PITR can either drop or 890 buffer the packets. This document does not have specific 891 recommendations about the action to be taken. It is up to the 892 deployer to consider whether or not it is desirable to buffer packets 893 and deploy a LISP implementation that offers the desired behaviour. 894 Once the mapping is resolved it is then stored in the local Map-Cache 895 to forward subsequent packets addressed to the same EID-prefix. 897 The Map-Cache is a local cache of mappings, entries are expired based 898 on the associated Time to live. In addition, entries can be updated 899 with more current information, see Section 13 for further information 900 on this. Finally, the Map-Cache also contains reachability 901 information about EIDs and RLOCs, and uses LISP reachability 902 information mechanisms to determine the reachability of RLOCs, see 903 Section 10 for the specific mechanisms. 905 7. Dealing with Large Encapsulated Packets 907 This section proposes two mechanisms to deal with packets that exceed 908 the path MTU between the ITR and ETR. 910 It is left to the implementor to decide if the stateless or stateful 911 mechanism SHOULD be implemented. Both or neither can be used, since 912 it is a local decision in the ITR regarding how to deal with MTU 913 issues, and sites can interoperate with differing mechanisms. 915 Both stateless and stateful mechanisms also apply to Re-encapsulating 916 and Recursive Tunneling, so any actions below referring to an ITR 917 also apply to a TE-ITR. 919 7.1. A Stateless Solution to MTU Handling 921 An ITR stateless solution to handle MTU issues is described as 922 follows: 924 1. Define H to be the size, in octets, of the outer header an ITR 925 prepends to a packet. This includes the UDP and LISP header 926 lengths. 928 2. Define L to be the size, in octets, of the maximum-sized packet 929 an ITR can send to an ETR without the need for the ITR or any 930 intermediate routers to fragment the packet. The network 931 administrator of the LISP deployment has to determine what is the 932 suitable value of L so to make sure that no MTU issues arise. 934 3. Define an architectural constant S for the maximum size of a 935 packet, in octets, an ITR MUST receive from the source so the 936 effective MTU can be met. That is, L = S + H. 938 When an ITR receives a packet from a site-facing interface and adds H 939 octets worth of encapsulation to yield a packet size greater than L 940 octets (meaning the received packet size was greater than S octets 941 from the source), it resolves the MTU issue by first splitting the 942 original packet into 2 equal-sized fragments. A LISP header is then 943 prepended to each fragment. The size of the encapsulated fragments 944 is then (S/2 + H), which is less than the ITR's estimate of the path 945 MTU between the ITR and its correspondent ETR. 947 When an ETR receives encapsulated fragments, it treats them as two 948 individually encapsulated packets. It strips the LISP headers and 949 then forwards each fragment to the destination host of the 950 destination site. The two fragments are reassembled at the 951 destination host into the single IP datagram that was originated by 952 the source host. Note that reassembly can happen at the ETR if the 953 encapsulated packet was fragmented at or after the ITR. 955 This behavior MUST be performed by the ITR only when the source host 956 originates a packet with the 'DF' field of the IP header set to 0. 957 When the 'DF' field of the IP header is set to 1, or the packet is an 958 IPv6 packet originated by the source host, the ITR will drop the 959 packet when the size (adding in the size of the encapsulation header) 960 is greater than L and send an ICMPv4 ICMP Unreachable/Fragmentation- 961 Needed or ICMPv6 "Packet Too Big" message to the source with a value 962 of S, where S is (L - H). 964 When the outer-header encapsulation uses an IPv4 header, an 965 implementation SHOULD set the DF bit to 1 so ETR fragment reassembly 966 can be avoided. An implementation MAY set the DF bit in such headers 967 to 0 if it has good reason to believe there are unresolvable path MTU 968 issues between the sending ITR and the receiving ETR. 970 This specification RECOMMENDS that L be defined as 1500. 972 7.2. A Stateful Solution to MTU Handling 974 An ITR stateful solution to handle MTU issues is described as 975 follows: 977 1. The ITR will keep state of the effective MTU for each Locator per 978 Map-Cache entry. The effective MTU is what the core network can 979 deliver along the path between the ITR and ETR. 981 2. When an IPv6-encapsulated packet, or an IPv4-encapsulated packet 982 with the DF bit set to 1, exceeds what the core network can 983 deliver, one of the intermediate routers on the path will send an 984 ICMPv6 "Packet Too Big" message or an ICMPv4 Unreachable/ 985 Fragmentation-Needed to the ITR, respectively. The ITR will 986 parse the ICMP message to determine which Locator is affected by 987 the effective MTU change and then record the new effective MTU 988 value in the Map-Cache entry. 990 3. When a packet is received by the ITR from a source inside of the 991 site and the size of the packet is greater than the effective MTU 992 stored with the Map-Cache entry associated with the destination 993 EID the packet is for, the ITR will send an ICMPv4 ICMP 994 Unreachable/Fragmentation-Needed or ICMPv6 "Packet Too Big" 995 message back to the source. The packet size advertised by the 996 ITR in the ICMP message is the effective MTU minus the LISP 997 encapsulation length. 999 Even though this mechanism is stateful, it has advantages over the 1000 stateless IP fragmentation mechanism, by not involving the 1001 destination host with reassembly of ITR fragmented packets. 1003 8. Using Virtualization and Segmentation with LISP 1005 There are several cases where segregation is needed at the EID level. 1006 For instance, this is the case for deployments containing overlapping 1007 addresses, traffic isolation policies or multi-tenant virtualization. 1008 For these and other scenarios where segregation is needed, Instance 1009 IDs are used. 1011 An Instance ID can be carried in a LISP-encapsulated packet. An ITR 1012 that prepends a LISP header will copy a 24-bit value used by the LISP 1013 router to uniquely identify the address space. The value is copied 1014 to the 'Instance ID' field of the LISP header, and the I-bit is set 1015 to 1. 1017 When an ETR decapsulates a packet, the Instance ID from the LISP 1018 header is used as a table identifier to locate the forwarding table 1019 to use for the inner destination EID lookup. 1021 For example, an 802.1Q VLAN tag or VPN identifier could be used as a 1022 24-bit Instance ID. See [I-D.ietf-lisp-vpn] for LISP VPN use-case 1023 details. 1025 Participants within a LISP deployment must agree on the meaning of 1026 Instance ID values. The source and destination EIDs MUST belong to 1027 the same Instance ID. 1029 9. Routing Locator Selection 1031 The Map-Cache contains the state used by ITRs and PITRs to 1032 encapsulate packets. When an ITR/PITR receives a packet from inside 1033 the LISP site to a destination outside of the site a longest-prefix 1034 match lookup of the EID is done to the Map-Cache (see Section 6). 1035 The lookup returns a single Locator-Set containing a list of RLOCs 1036 corresponding to the EID's topological location. Each RLOC in the 1037 Locator-Set is associated with a 'Priority' and 'Weight', this 1038 information is used to select the RLOC to encapsulate. 1040 The RLOC with the lowest 'Priority' is selected. An RLOC with 1041 'Priority' 255 means that MUST NOT be used for forwarding. When 1042 multiple RLOC have the same 'Priority' then the 'Weight' states how 1043 to load balance traffic among them. The value of the 'Weight' 1044 represents the relative weight of the total packets that match the 1045 maping entry. 1047 The following are different scenarios for choosing RLOCs and the 1048 controls that are available: 1050 o The server-side returns one RLOC. The client-side can only use 1051 one RLOC. The server-side has complete control of the selection. 1053 o The server-side returns a list of RLOCs where a subset of the list 1054 has the same best Priority. The client can only use the subset 1055 list according to the weighting assigned by the server-side. In 1056 this case, the server-side controls both the subset list and load- 1057 splitting across its members. The client-side can use RLOCs 1058 outside of the subset list if it determines that the subset list 1059 is unreachable (unless RLOCs are set to a Priority of 255). Some 1060 sharing of control exists: the server-side determines the 1061 destination RLOC list and load distribution while the client-side 1062 has the option of using alternatives to this list if RLOCs in the 1063 list are unreachable. 1065 o The server-side sets a Weight of zero for the RLOC subset list. 1066 In this case, the client-side can choose how the traffic load is 1067 spread across the subset list. See Section 12 for details on 1068 load-sharing mechanisms. Control is shared by the server-side 1069 determining the list and the client-side determining load 1070 distribution. Again, the client can use alternative RLOCs if the 1071 server-provided list of RLOCs is unreachable. 1073 o Either side (more likely the server-side ETR) decides to "glean" 1074 the RLOCs. For example, if the server-side ETR gleans RLOCs, then 1075 the client-side ITR gives the client-side ITR responsibility for 1076 bidirectional RLOC reachability and preferability. Server-side 1077 ETR gleaning of the client-side ITR RLOC is done by caching the 1078 inner-header source EID and the outer-header source RLOC of 1079 received packets. The client-side ITR controls how traffic is 1080 returned and can alternate using an outer-header source RLOC, 1081 which then can be added to the list the server-side ETR uses to 1082 return traffic. Since no Priority or Weights are provided using 1083 this method, the server-side ETR MUST assume that each client-side 1084 ITR RLOC uses the same best Priority with a Weight of zero. In 1085 addition, since EID-Prefix encoding cannot be conveyed in data 1086 packets, the EID-to-RLOC Cache on Tunnel Routers can grow to be 1087 very large. Gleaning has several important considerations. A 1088 "gleaned" Map-Cache entry is only stored and used for a few 1089 seconds, pending verification. Verification is performed by 1090 sending a Map-Request to the source EID (the inner-header IP 1091 source address) of the received encapsulated packet. A reply to 1092 this "verifying Map-Request" is used to fully populate the Map- 1093 Cache entry for the "gleaned" EID and is stored and used for the 1094 time indicated from the 'TTL' field of a received Map-Reply. When 1095 a verified Map- Cache entry is stored, data gleaning no longer 1096 occurs for subsequent packets that have a source EID that matches 1097 the EID-Prefix of the verified entry. This "gleaning" mechanism 1098 SHOULD NOT be used over the public Internet and SHOULD only be 1099 used in trusted and closed deployments. Refer to Section 16 for 1100 security issues regarding this mechanism. 1102 RLOCs that appear in EID-to-RLOC Map-Reply messages are assumed to be 1103 reachable when the R-bit [I-D.ietf-lisp-rfc6833bis] for the Locator 1104 record is set to 1. When the R-bit is set to 0, an ITR or PITR MUST 1105 NOT encapsulate to the RLOC. Neither the information contained in a 1106 Map-Reply nor that stored in the mapping database system provides 1107 reachability information for RLOCs. Note that reachability is not 1108 part of the mapping system and is determined using one or more of the 1109 Routing Locator reachability algorithms described in the next 1110 section. 1112 10. Routing Locator Reachability 1114 Several Data-Plane mechanisms for determining RLOC reachability are 1115 currently defined. Please note that additional Control-Plane based 1116 reachability mechanisms are defined in [I-D.ietf-lisp-rfc6833bis]. 1118 1. An ETR MAY examine the Locator-Status-Bits in the LISP header of 1119 an encapsulated data packet received from an ITR. If the ETR is 1120 also acting as an ITR and has traffic to return to the original 1121 ITR site, it can use this status information to help select an 1122 RLOC. 1124 2. When an ETR receives an encapsulated packet from an ITR, the 1125 source RLOC from the outer header of the packet is likely to be 1126 reachable. Please note that in some scenarios the RLOC from the 1127 outer header can be an spoofable field. 1129 3. An ITR/ETR pair can use the 'Echo-Noncing' Locator reachability 1130 algorithms described in this section. 1132 When determining Locator up/down reachability by examining the 1133 Locator-Status-Bits from the LISP-encapsulated data packet, an ETR 1134 will receive up-to-date status from an encapsulating ITR about 1135 reachability for all ETRs at the site. CE-based ITRs at the source 1136 site can determine reachability relative to each other using the site 1137 IGP as follows: 1139 o Under normal circumstances, each ITR will advertise a default 1140 route into the site IGP. 1142 o If an ITR fails or if the upstream link to its PE fails, its 1143 default route will either time out or be withdrawn. 1145 Each ITR can thus observe the presence or lack of a default route 1146 originated by the others to determine the Locator-Status-Bits it sets 1147 for them. 1149 When ITRs at the site are not deployed in CE routers, the IGP can 1150 still be used to determine the reachability of Locators, provided 1151 they are injected into the IGP. This is typically done when a /32 1152 address is configured on a loopback interface. 1154 RLOCs listed in a Map-Reply are numbered with ordinals 0 to n-1. The 1155 Locator-Status-Bits in a LISP-encapsulated packet are numbered from 0 1156 to n-1 starting with the least significant bit. For example, if an 1157 RLOC listed in the 3rd position of the Map-Reply goes down (ordinal 1158 value 2), then all ITRs at the site will clear the 3rd least 1159 significant bit (xxxx x0xx) of the 'Locator-Status-Bits' field for 1160 the packets they encapsulate. 1162 When an xTR decides to use 'Locator-Status-Bits' to affect 1163 reachability information, it acts as follows: ETRs decapsulating a 1164 packet will check for any change in the 'Locator-Status-Bits' field. 1165 When a bit goes from 1 to 0, the ETR, if acting also as an ITR, will 1166 refrain from encapsulating packets to an RLOC that is indicated as 1167 down. It will only resume using that RLOC if the corresponding 1168 Locator-Status-Bit returns to a value of 1. Locator-Status-Bits are 1169 associated with a Locator-Set per EID-Prefix. Therefore, when a 1170 Locator becomes unreachable, the Locator-Status-Bit that corresponds 1171 to that Locator's position in the list returned by the last Map-Reply 1172 will be set to zero for that particular EID-Prefix. 1174 Locator-Status-Bits SHOULD NOT be used over the public Internet and 1175 SHOULD only be used in trusted and closed deployments. In addition 1176 Locator-Status-Bits SHOULD be coupled with Map-Versioning 1177 (Section 13.2) to prevent race conditions where Locator-Status-Bits 1178 are interpreted as referring to different RLOCs than intended. Refer 1179 to Section 16 for security issues regarding this mechanism. 1181 If an ITR encapsulates a packet to an ETR and the packet is received 1182 and decapsulated by the ETR, it is implied but not confirmed by the 1183 ITR that the ETR's RLOC is reachable. In most cases, the ETR can 1184 also reach the ITR but cannot assume this to be true, due to the 1185 possibility of path asymmetry. In the presence of unidirectional 1186 traffic flow from an ITR to an ETR, the ITR SHOULD NOT use the lack 1187 of return traffic as an indication that the ETR is unreachable. 1188 Instead, it MUST use an alternate mechanism to determine 1189 reachability. 1191 The security considerations of Section 16 related to data-plane 1192 reachability applies to the data-plane RLOC reachability mechanisms 1193 described in this section. 1195 10.1. Echo Nonce Algorithm 1197 When data flows bidirectionally between Locators from different 1198 sites, a Data-Plane mechanism called "nonce echoing" can be used to 1199 determine reachability between an ITR and ETR. When an ITR wants to 1200 solicit a nonce echo, it sets the N- and E-bits and places a 24-bit 1201 nonce [RFC4086] in the LISP header of the next encapsulated data 1202 packet. 1204 When this packet is received by the ETR, the encapsulated packet is 1205 forwarded as normal. When the ETR is an xTR (co-located as an ITR), 1206 it then sends a data packet to the ITR (when it is an xTR co-located 1207 as an ETR), it includes the nonce received earlier with the N-bit set 1208 and E-bit cleared. The ITR sees this "echoed nonce" and knows that 1209 the path to and from the ETR is up. 1211 The ITR will set the E-bit and N-bit for every packet it sends while 1212 in the echo-nonce-request state. The time the ITR waits to process 1213 the echoed nonce before it determines the path is unreachable is 1214 variable and is a choice left for the implementation. 1216 If the ITR is receiving packets from the ETR but does not see the 1217 nonce echoed while being in the echo-nonce-request state, then the 1218 path to the ETR is unreachable. This decision MAY be overridden by 1219 other Locator reachability algorithms. Once the ITR determines that 1220 the path to the ETR is down, it can switch to another Locator for 1221 that EID-Prefix. 1223 Note that "ITR" and "ETR" are relative terms here. Both devices MUST 1224 be implementing both ITR and ETR functionality for the echo nonce 1225 mechanism to operate. 1227 The ITR and ETR MAY both go into the echo-nonce-request state at the 1228 same time. The number of packets sent or the time during which echo 1229 nonce requests are sent is an implementation-specific setting. In 1230 this case, an xTR receiving the echo-nonce-request packets will 1231 suspend the echo-nonce-request state and setup a 'echo-nonce-request- 1232 state' timer. After the 'echo-nonce-request-state' timer expires it 1233 will resume the echo-nonce-request state. 1235 This mechanism does not completely solve the forward path 1236 reachability problem, as traffic may be unidirectional. That is, the 1237 ETR receiving traffic at a site MAY not be the same device as an ITR 1238 that transmits traffic from that site, or the site-to-site traffic is 1239 unidirectional so there is no ITR returning traffic. 1241 The echo-nonce algorithm is bilateral. That is, if one side sets the 1242 E-bit and the other side is not enabled for echo-noncing, then the 1243 echoing of the nonce does not occur and the requesting side may 1244 erroneously consider the Locator unreachable. An ITR SHOULD set the 1245 E-bit in an encapsulated data packet when it knows the ETR is enabled 1246 for echo-noncing. This is conveyed by the E-bit in the Map-Reply 1247 message. 1249 Many implementations default to not advertising they are echo-nonce 1250 capable in Map-Reply messages and so RLOC-probing tends to be used 1251 for RLOC reachability. 1253 The echo-nonce mechanism SHOULD NOT be used over the public Internet 1254 and SHOULD only be used in trusted and closed deployments. Refer to 1255 Section 16 for security issues regarding this mechanism. 1257 11. EID Reachability within a LISP Site 1259 A site MAY be multihomed using two or more ETRs. The hosts and 1260 infrastructure within a site will be addressed using one or more EID- 1261 Prefixes that are mapped to the RLOCs of the relevant ETRs in the 1262 mapping system. One possible failure mode is for an ETR to lose 1263 reachability to one or more of the EID-Prefixes within its own site. 1264 When this occurs when the ETR sends Map-Replies, it can clear the 1265 R-bit associated with its own Locator. And when the ETR is also an 1266 ITR, it can clear its Locator-Status-Bit in the encapsulation data 1267 header. 1269 It is recognized that there are no simple solutions to the site 1270 partitioning problem because it is hard to know which part of the 1271 EID-Prefix range is partitioned and which Locators can reach any sub- 1272 ranges of the EID-Prefixes. Note that this is not a new problem 1273 introduced by the LISP architecture. The problem exists today when a 1274 multihomed site uses BGP to advertise its reachability upstream. 1276 12. Routing Locator Hashing 1278 When an ETR provides an EID-to-RLOC mapping in a Map-Reply message 1279 that is stored in the Map-Cache of a requesting ITR, the Locator-Set 1280 for the EID-Prefix MAY contain different Priority and Weight values 1281 for each locator address. When more than one best Priority Locator 1282 exists, the ITR can decide how to load-share traffic against the 1283 corresponding Locators. 1285 The following hash algorithm MAY be used by an ITR to select a 1286 Locator for a packet destined to an EID for the EID-to-RLOC mapping: 1288 1. Either a source and destination address hash or the traditional 1289 5-tuple hash can be used. The traditional 5-tuple hash includes 1290 the source and destination addresses; source and destination TCP, 1291 UDP, or Stream Control Transmission Protocol (SCTP) port numbers; 1292 and the IP protocol number field or IPv6 next-protocol fields of 1293 a packet that a host originates from within a LISP site. When a 1294 packet is not a TCP, UDP, or SCTP packet, the source and 1295 destination addresses only from the header are used to compute 1296 the hash. 1298 2. Take the hash value and divide it by the number of Locators 1299 stored in the Locator-Set for the EID-to-RLOC mapping. 1301 3. The remainder will yield a value of 0 to "number of Locators 1302 minus 1". Use the remainder to select the Locator in the 1303 Locator-Set. 1305 The specific hash algorithm the ITR uses for load-sharing is out of 1306 scope for this document and does not prevent interoperability. 1308 The Source port SHOULD be the same for all packets belonging to the 1309 same flow. Also note that when a packet is LISP encapsulated, the 1310 source port number in the outer UDP header needs to be set. 1311 Selecting a hashed value allows core routers that are attached to 1312 Link Aggregation Groups (LAGs) to load-split the encapsulated packets 1313 across member links of such LAGs. Otherwise, core routers would see 1314 a single flow, since packets have a source address of the ITR, for 1315 packets that are originated by different EIDs at the source site. A 1316 suggested setting for the source port number computed by an ITR is a 1317 5-tuple hash function on the inner header, as described above. The 1318 source port SHOULD be the same for all packets belonging to the same 1319 flow. 1321 Many core router implementations use a 5-tuple hash to decide how to 1322 balance packet load across members of a LAG. The 5-tuple hash 1323 includes the source and destination addresses of the packet and the 1324 source and destination ports when the protocol number in the packet 1325 is TCP or UDP. For this reason, UDP encoding is used for LISP 1326 encapsulation. 1328 13. Changing the Contents of EID-to-RLOC Mappings 1330 Since the LISP architecture uses a caching scheme to retrieve and 1331 store EID-to-RLOC mappings, the only way an ITR can get a more up-to- 1332 date mapping is to re-request the mapping. However, the ITRs do not 1333 know when the mappings change, and the ETRs do not keep track of 1334 which ITRs requested its mappings. For scalability reasons, it is 1335 desirable to maintain this approach but need to provide a way for 1336 ETRs to change their mappings and inform the sites that are currently 1337 communicating with the ETR site using such mappings. 1339 This section defines two Data-Plane mechanism for updating EID-to- 1340 RLOC mappings. Additionally, the Solicit-Map Request (SMR) Control- 1341 Plane updating mechanism is specified in [I-D.ietf-lisp-rfc6833bis]. 1343 13.1. Locator-Status-Bits 1345 Locator-Status-Bits (LSB) can also be used to keep track of the 1346 Locator status (up or down) when EID-to-RLOC mappings are changing. 1347 When LSB are used in a LISP deployment, all LISP tunnel routers MUST 1348 implement both ITR and ETR capabilities (therefore all tunnel routers 1349 are effectively xTRs). In this section the term "source xTR" is used 1350 to refer to the xTR setting the LSB and "destination xTR" is used to 1351 refer to the xTR receiving the LSB. The procedure is as follows: 1353 First, when a Locator record is added or removed from the Locator- 1354 Set, the source xTR will signal this by sending a Solicit-Map Request 1355 (SMR) Control-Plane message [I-D.ietf-lisp-rfc6833bis] to the 1356 destination xTR. At this point the source xTR MUST NOT use LSB 1357 (L-bit = 0) since the destination xTR site has outdated information. 1358 The source xTR will setup a 'use-LSB' timer. 1360 Second and as defined in [I-D.ietf-lisp-rfc6833bis], upon reception 1361 of the SMR message the destination xTR will retrieve the updated EID- 1362 to-RLOC mappings by sending a Map-Request. 1364 And third, when the 'use-LSB' timer expires, the source xTR can use 1365 again LSB with the destination xTR to signal the Locator status (up 1366 or down). The specific value for the 'use-LSB' timer depends on the 1367 LISP deployment, the 'use-LSB' timer needs to be large enough for the 1368 destination xTR to retreive the updated EID-to-RLOC mappings. A 1369 RECOMMENDED value for the 'use-LSB' timer is 5 minutes. 1371 13.2. Database Map-Versioning 1373 When there is unidirectional packet flow between an ITR and ETR, and 1374 the EID-to-RLOC mappings change on the ETR, it needs to inform the 1375 ITR so encapsulation to a removed Locator can stop and can instead be 1376 started to a new Locator in the Locator-Set. 1378 An ETR, when it sends Map-Reply messages, conveys its own Map-Version 1379 Number. This is known as the Destination Map-Version Number. ITRs 1380 include the Destination Map-Version Number in packets they 1381 encapsulate to the site. When an ETR decapsulates a packet and 1382 detects that the Destination Map-Version Number is less than the 1383 current version for its mapping, the SMR procedure described in 1384 [I-D.ietf-lisp-rfc6833bis] occurs. 1386 An ITR, when it encapsulates packets to ETRs, can convey its own Map- 1387 Version Number. This is known as the Source Map-Version Number. 1388 When an ETR decapsulates a packet and detects that the Source Map- 1389 Version Number is greater than the last Map-Version Number sent in a 1390 Map-Reply from the ITR's site, the ETR will send a Map-Request to one 1391 of the ETRs for the source site. 1393 A Map-Version Number is used as a sequence number per EID-Prefix, so 1394 values that are greater are considered to be more recent. A value of 1395 0 for the Source Map-Version Number or the Destination Map-Version 1396 Number conveys no versioning information, and an ITR does no 1397 comparison with previously received Map-Version Numbers. 1399 A Map-Version Number can be included in Map-Register messages as 1400 well. This is a good way for the Map-Server to assure that all ETRs 1401 for a site registering to it will be synchronized according to Map- 1402 Version Number. 1404 Map-Version requires that ETRs within the LISP site are synchronized 1405 with respect to the Map-Version Number, EID-prefix and the set and 1406 status (up/down) of the RLOCs. The use of Map-Versioning without 1407 proper synzhronization may cause traffic disruption. The 1408 synchronization protocol is out-of-the-scope of this document, but 1409 MUST keep ETRs synchronized within a 1 minute window. 1411 Map-Versioning SHOULD NOT be used over the public Internet and SHOULD 1412 only be used in trusted and closed deployments. Refer to Section 16 1413 for security issues regarding this mechanism. 1415 See [I-D.ietf-lisp-6834bis] for a more detailed analysis and 1416 description of Database Map-Versioning. 1418 14. Multicast Considerations 1420 A multicast group address, as defined in the original Internet 1421 architecture, is an identifier of a grouping of topologically 1422 independent receiver host locations. The address encoding itself 1423 does not determine the location of the receiver(s). The multicast 1424 routing protocol, and the network-based state the protocol creates, 1425 determine where the receivers are located. 1427 In the context of LISP, a multicast group address is both an EID and 1428 a Routing Locator. Therefore, no specific semantic or action needs 1429 to be taken for a destination address, as it would appear in an IP 1430 header. Therefore, a group address that appears in an inner IP 1431 header built by a source host will be used as the destination EID. 1432 The outer IP header (the destination Routing Locator address), 1433 prepended by a LISP router, can use the same group address as the 1434 destination Routing Locator, use a multicast or unicast Routing 1435 Locator obtained from a Mapping System lookup, or use other means to 1436 determine the group address mapping. 1438 With respect to the source Routing Locator address, the ITR prepends 1439 its own IP address as the source address of the outer IP header, just 1440 like it would if the destination EID was a unicast address. This 1441 source Routing Locator address, like any other Routing Locator 1442 address, MUST be routable on the underlay. 1444 There are two approaches for LISP-Multicast, one that uses native 1445 multicast routing in the underlay with no support from the Mapping 1446 System and the other that uses only unicast routing in the underlay 1447 with support from the Mapping System. See [RFC6831] and [RFC8378], 1448 respectively, for details. Details for LISP-Multicast and 1449 interworking with non-LISP sites are described in [RFC6831] and 1450 [RFC6832]. 1452 15. Router Performance Considerations 1454 LISP is designed to be very "hardware-based forwarding friendly". A 1455 few implementation techniques can be used to incrementally implement 1456 LISP: 1458 o When a tunnel-encapsulated packet is received by an ETR, the outer 1459 destination address may not be the address of the router. This 1460 makes it challenging for the control plane to get packets from the 1461 hardware. This may be mitigated by creating special Forwarding 1462 Information Base (FIB) entries for the EID-Prefixes of EIDs served 1463 by the ETR (those for which the router provides an RLOC 1464 translation). These FIB entries are marked with a flag indicating 1465 that Control-Plane processing SHOULD be performed. The forwarding 1466 logic of testing for particular IP protocol number values is not 1467 necessary. There are a few proven cases where no changes to 1468 existing deployed hardware were needed to support the LISP Data- 1469 Plane. 1471 o On an ITR, prepending a new IP header consists of adding more 1472 octets to a MAC rewrite string and prepending the string as part 1473 of the outgoing encapsulation procedure. Routers that support 1474 Generic Routing Encapsulation (GRE) tunneling [RFC2784] or 6to4 1475 tunneling [RFC3056] may already support this action. 1477 o A packet's source address or interface the packet was received on 1478 can be used to select VRF (Virtual Routing/Forwarding). The VRF's 1479 routing table can be used to find EID-to-RLOC mappings. 1481 For performance issues related to Map-Cache management, see 1482 Section 16. 1484 16. Security Considerations 1486 In what follows we highlight security considerations that apply when 1487 LISP is deployed in environments such as those specified in 1488 Section 1.1. 1490 The optional mechanisms of gleaning is offered to directly obtain a 1491 mapping from the LISP encapsulated packets. Specifically, an xTR can 1492 learn the EID-to-RLOC mapping by inspecting the source RLOC and 1493 source EID of an encapsulated packet, and insert this new mapping 1494 into its Map-Cache. An off-path attacker can spoof the source EID 1495 address to divert the traffic sent to the victim's spoofed EID. If 1496 the attacker spoofs the source RLOC, it can mount a DoS attack by 1497 redirecting traffic to the spoofed victim's RLOC, potentially 1498 overloading it. 1500 The LISP Data-Plane defines several mechanisms to monitor RLOC Data- 1501 Plane reachability, in this context Locator-Status Bits, Nonce- 1502 Present and Echo-Nonce bits of the LISP encapsulation header can be 1503 manipulated by an attacker to mount a DoS attack. An off-path 1504 attacker able to spoof the RLOC and/or nonce of a victim's xTR can 1505 manipulate such mechanisms to declare false information about the 1506 RLOC's reachability status. 1508 For example of such attacks, an off-path attacker can exploit the 1509 echo-nonce mechanism by sending data packets to an ITR with a random 1510 nonce from an ETR's spoofed RLOC. Note the attacker must guess a 1511 valid nonce the ITR is requesting to be echoed within a small window 1512 of time. The goal is to convince the ITR that the ETR's RLOC is 1513 reachable even when it may not be reachable. If the attack is 1514 successful, the ITR believes the wrong reachability status of the 1515 ETR's RLOC until RLOC-probing detects the correct status. This time 1516 frame is on the order of 10s of seconds. This specific attack can be 1517 mitigated by preventing RLOC spoofing in the network by deploying 1518 uRPF BCP 38 [RFC2827]. In addition and in order to exploit this 1519 vulnerability, the off-path attacker must send echo-nonce packets at 1520 high rate. If the nonces have never been requested by the ITR, it 1521 can protect itself from erroneous reachability attacks. 1523 Map-Versioning is a Data-Plane mechanism used to signal a peering xTR 1524 that a local EID-to-RLOC mapping has been updated, so that the 1525 peering xTR uses LISP Control-Plane signaling message to retrieve a 1526 fresh mapping. This can be used by an attacker to forge the map- 1527 versioning field of a LISP encapsulated header and force an excessive 1528 amount of signaling between xTRs that may overload them. 1530 Locator-Status-Bits, echo-nonce and map-versioning SHOULD NOT be used 1531 over the public Internet and SHOULD only be used in trusted and 1532 closed deployments. In addition Locator-Status-Bits SHOULD be 1533 coupled with map-versioning to prevent race conditions where Locator- 1534 Status-Bits are interpreted as referring to different RLOCs than 1535 intended. 1537 LISP implementations and deployments which permit outer header 1538 fragments of IPv6 LISP encapsulated packets as a means of dealing 1539 with MTU issues should also use implementation techniques in ETRs to 1540 prevent this from being a DoS attack vector. Limits on the number of 1541 fragments awaiting reassembly at an ETR, RTR, or PETR, and the rate 1542 of admitting such fragments may be used. 1544 17. Network Management Considerations 1546 Considerations for network management tools exist so the LISP 1547 protocol suite can be operationally managed. These mechanisms can be 1548 found in [RFC7052] and [RFC6835]. 1550 18. Changes since RFC 6830 1552 For implementation considerations, the following changes have been 1553 made to this document since RFC 6830 was published: 1555 o It is no longer mandated that a maximum number of 2 LISP headers 1556 be prepended to a packet. If there is a application need for more 1557 than 2 LISP headers, an implementation can support more. However, 1558 it is RECOMMENDED that a maximum of two LISP headers can be 1559 prepended to a packet. 1561 o The 3 reserved flag bits in the LISP header have been allocated 1562 for [RFC8061]. The low-order 2 bits of the 3-bit field (now named 1563 the KK bits) are used as a key identifier. The 1 remaining bit is 1564 still documented as reserved and unassigned. 1566 o Data-Plane gleaning for creating map-cache entries has been made 1567 optional. Any ITR implementations that depend on or assume the 1568 remote ETR is gleaning should not do so. This does not create any 1569 interoperability problems since the control-plane map-cache 1570 population procedures are unilateral and are the typical method 1571 for map-cache population. 1573 o The bulk of the changes to this document which reduces its length 1574 are due to moving the LISP control-plane messaging and procedures 1575 to [I-D.ietf-lisp-rfc6833bis]. 1577 19. IANA Considerations 1579 This section provides guidance to the Internet Assigned Numbers 1580 Authority (IANA) regarding registration of values related to this 1581 Data-Plane LISP specification, in accordance with BCP 26 [RFC8126]. 1583 19.1. LISP UDP Port Numbers 1585 The IANA registry has allocated UDP port number 4341 for the LISP 1586 Data-Plane. IANA has updated the description for UDP port 4341 as 1587 follows: 1589 lisp-data 4341 udp LISP Data Packets 1591 20. References 1593 20.1. Normative References 1595 [I-D.ietf-lisp-6834bis] 1596 Iannone, L., Saucez, D., and O. Bonaventure, "Locator/ID 1597 Separation Protocol (LISP) Map-Versioning", draft-ietf- 1598 lisp-6834bis-06 (work in progress), February 2020. 1600 [I-D.ietf-lisp-rfc6833bis] 1601 Farinacci, D., Maino, F., Fuller, V., and A. Cabellos- 1602 Aparicio, "Locator/ID Separation Protocol (LISP) Control- 1603 Plane", draft-ietf-lisp-rfc6833bis-27 (work in progress), 1604 January 2020. 1606 [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, 1607 DOI 10.17487/RFC0768, August 1980, 1608 . 1610 [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, 1611 DOI 10.17487/RFC0791, September 1981, 1612 . 1614 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1615 Requirement Levels", BCP 14, RFC 2119, 1616 DOI 10.17487/RFC2119, March 1997, 1617 . 1619 [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, 1620 "Definition of the Differentiated Services Field (DS 1621 Field) in the IPv4 and IPv6 Headers", RFC 2474, 1622 DOI 10.17487/RFC2474, December 1998, 1623 . 1625 [RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering: 1626 Defeating Denial of Service Attacks which employ IP Source 1627 Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827, 1628 May 2000, . 1630 [RFC6040] Briscoe, B., "Tunnelling of Explicit Congestion 1631 Notification", RFC 6040, DOI 10.17487/RFC6040, November 1632 2010, . 1634 [RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The 1635 Locator/ID Separation Protocol (LISP)", RFC 6830, 1636 DOI 10.17487/RFC6830, January 2013, 1637 . 1639 [RFC6831] Farinacci, D., Meyer, D., Zwiebel, J., and S. Venaas, "The 1640 Locator/ID Separation Protocol (LISP) for Multicast 1641 Environments", RFC 6831, DOI 10.17487/RFC6831, January 1642 2013, . 1644 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1645 Writing an IANA Considerations Section in RFCs", BCP 26, 1646 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1647 . 1649 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1650 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1651 May 2017, . 1653 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1654 (IPv6) Specification", STD 86, RFC 8200, 1655 DOI 10.17487/RFC8200, July 2017, 1656 . 1658 [RFC8378] Moreno, V. and D. Farinacci, "Signal-Free Locator/ID 1659 Separation Protocol (LISP) Multicast", RFC 8378, 1660 DOI 10.17487/RFC8378, May 2018, 1661 . 1663 20.2. Informative References 1665 [AFN] IANA, "Address Family Numbers", August 2016, 1666 . 1668 [CHIAPPA] Chiappa, J., "Endpoints and Endpoint names: A Proposed", 1669 1999, 1670 . 1672 [I-D.ietf-lisp-introduction] 1673 Cabellos-Aparicio, A. and D. Saucez, "An Architectural 1674 Introduction to the Locator/ID Separation Protocol 1675 (LISP)", draft-ietf-lisp-introduction-13 (work in 1676 progress), April 2015. 1678 [I-D.ietf-lisp-vpn] 1679 Moreno, V. and D. Farinacci, "LISP Virtual Private 1680 Networks (VPNs)", draft-ietf-lisp-vpn-05 (work in 1681 progress), November 2019. 1683 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 1684 STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, 1685 . 1687 [RFC1918] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G., 1688 and E. Lear, "Address Allocation for Private Internets", 1689 BCP 5, RFC 1918, DOI 10.17487/RFC1918, February 1996, 1690 . 1692 [RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. 1693 Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, 1694 DOI 10.17487/RFC2784, March 2000, 1695 . 1697 [RFC3056] Carpenter, B. and K. Moore, "Connection of IPv6 Domains 1698 via IPv4 Clouds", RFC 3056, DOI 10.17487/RFC3056, February 1699 2001, . 1701 [RFC3232] Reynolds, J., Ed., "Assigned Numbers: RFC 1700 is Replaced 1702 by an On-line Database", RFC 3232, DOI 10.17487/RFC3232, 1703 January 2002, . 1705 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, 1706 A., Peterson, J., Sparks, R., Handley, M., and E. 1707 Schooler, "SIP: Session Initiation Protocol", RFC 3261, 1708 DOI 10.17487/RFC3261, June 2002, 1709 . 1711 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 1712 "Randomness Requirements for Security", BCP 106, RFC 4086, 1713 DOI 10.17487/RFC4086, June 2005, 1714 . 1716 [RFC4984] Meyer, D., Ed., Zhang, L., Ed., and K. Fall, Ed., "Report 1717 from the IAB Workshop on Routing and Addressing", 1718 RFC 4984, DOI 10.17487/RFC4984, September 2007, 1719 . 1721 [RFC6832] Lewis, D., Meyer, D., Farinacci, D., and V. Fuller, 1722 "Interworking between Locator/ID Separation Protocol 1723 (LISP) and Non-LISP Sites", RFC 6832, 1724 DOI 10.17487/RFC6832, January 2013, 1725 . 1727 [RFC6835] Farinacci, D. and D. Meyer, "The Locator/ID Separation 1728 Protocol Internet Groper (LIG)", RFC 6835, 1729 DOI 10.17487/RFC6835, January 2013, 1730 . 1732 [RFC6935] Eubanks, M., Chimento, P., and M. Westerlund, "IPv6 and 1733 UDP Checksums for Tunneled Packets", RFC 6935, 1734 DOI 10.17487/RFC6935, April 2013, 1735 . 1737 [RFC6936] Fairhurst, G. and M. Westerlund, "Applicability Statement 1738 for the Use of IPv6 UDP Datagrams with Zero Checksums", 1739 RFC 6936, DOI 10.17487/RFC6936, April 2013, 1740 . 1742 [RFC7052] Schudel, G., Jain, A., and V. Moreno, "Locator/ID 1743 Separation Protocol (LISP) MIB", RFC 7052, 1744 DOI 10.17487/RFC7052, October 2013, 1745 . 1747 [RFC7215] Jakab, L., Cabellos-Aparicio, A., Coras, F., Domingo- 1748 Pascual, J., and D. Lewis, "Locator/Identifier Separation 1749 Protocol (LISP) Network Element Deployment 1750 Considerations", RFC 7215, DOI 10.17487/RFC7215, April 1751 2014, . 1753 [RFC7833] Howlett, J., Hartman, S., and A. Perez-Mendez, Ed., "A 1754 RADIUS Attribute, Binding, Profiles, Name Identifier 1755 Format, and Confirmation Methods for the Security 1756 Assertion Markup Language (SAML)", RFC 7833, 1757 DOI 10.17487/RFC7833, May 2016, 1758 . 1760 [RFC7835] Saucez, D., Iannone, L., and O. Bonaventure, "Locator/ID 1761 Separation Protocol (LISP) Threat Analysis", RFC 7835, 1762 DOI 10.17487/RFC7835, April 2016, 1763 . 1765 [RFC8060] Farinacci, D., Meyer, D., and J. Snijders, "LISP Canonical 1766 Address Format (LCAF)", RFC 8060, DOI 10.17487/RFC8060, 1767 February 2017, . 1769 [RFC8061] Farinacci, D. and B. Weis, "Locator/ID Separation Protocol 1770 (LISP) Data-Plane Confidentiality", RFC 8061, 1771 DOI 10.17487/RFC8061, February 2017, 1772 . 1774 [RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage 1775 Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085, 1776 March 2017, . 1778 [RFC8111] Fuller, V., Lewis, D., Ermagan, V., Jain, A., and A. 1779 Smirnov, "Locator/ID Separation Protocol Delegated 1780 Database Tree (LISP-DDT)", RFC 8111, DOI 10.17487/RFC8111, 1781 May 2017, . 1783 Appendix A. Acknowledgments 1785 An initial thank you goes to Dave Oran for planting the seeds for the 1786 initial ideas for LISP. His consultation continues to provide value 1787 to the LISP authors. 1789 A special and appreciative thank you goes to Noel Chiappa for 1790 providing architectural impetus over the past decades on separation 1791 of location and identity, as well as detailed reviews of the LISP 1792 architecture and documents, coupled with enthusiasm for making LISP a 1793 practical and incremental transition for the Internet. 1795 The original authors would like to gratefully acknowledge many people 1796 who have contributed discussions and ideas to the making of this 1797 proposal. They include Scott Brim, Andrew Partan, John Zwiebel, 1798 Jason Schiller, Lixia Zhang, Dorian Kim, Peter Schoenmaker, Vijay 1799 Gill, Geoff Huston, David Conrad, Mark Handley, Ron Bonica, Ted 1800 Seely, Mark Townsley, Chris Morrow, Brian Weis, Dave McGrew, Peter 1801 Lothberg, Dave Thaler, Eliot Lear, Shane Amante, Ved Kafle, Olivier 1802 Bonaventure, Luigi Iannone, Robin Whittle, Brian Carpenter, Joel 1803 Halpern, Terry Manderson, Roger Jorgensen, Ran Atkinson, Stig Venaas, 1804 Iljitsch van Beijnum, Roland Bless, Dana Blair, Bill Lynch, Marc 1805 Woolward, Damien Saucez, Damian Lezama, Attilla De Groot, Parantap 1806 Lahiri, David Black, Roque Gagliano, Isidor Kouvelas, Jesper Skriver, 1807 Fred Templin, Margaret Wasserman, Sam Hartman, Michael Hofling, Pedro 1808 Marques, Jari Arkko, Gregg Schudel, Srinivas Subramanian, Amit Jain, 1809 Xu Xiaohu, Dhirendra Trivedi, Yakov Rekhter, John Scudder, John 1810 Drake, Dimitri Papadimitriou, Ross Callon, Selina Heimlich, Job 1811 Snijders, Vina Ermagan, Fabio Maino, Victor Moreno, Chris White, 1812 Clarence Filsfils, Alia Atlas, Florin Coras and Alberto Rodriguez. 1814 This work originated in the Routing Research Group (RRG) of the IRTF. 1815 An individual submission was converted into the IETF LISP working 1816 group document that became this RFC. 1818 The LISP working group would like to give a special thanks to Jari 1819 Arkko, the Internet Area AD at the time that the set of LISP 1820 documents were being prepared for IESG last call, and for his 1821 meticulous reviews and detailed commentaries on the 7 working group 1822 last call documents progressing toward standards-track RFCs. 1824 The current authors would like to give a sincere thank you to the 1825 people who help put LISP on standards track in the IETF. They 1826 include Joel Halpern, Luigi Iannone, Deborah Brungard, Fabio Maino, 1827 Scott Bradner, Kyle Rose, Takeshi Takahashi, Sarah Banks, Pete 1828 Resnick, Colin Perkins, Mirja Kuhlewind, Francis Dupont, Benjamin 1829 Kaduk, Eric Rescorla, Alvaro Retana, Alexey Melnikov, Alissa Cooper, 1830 Suresh Krishnan, Alberto Rodriguez-Natal, Vina Ermagen, Mohamed 1831 Boucadair, Brian Trammell, Sabrina Tanamal, and John Drake. The 1832 contributions they offered greatly added to the security, scale, and 1833 robustness of the LISP architecture and protocols. 1835 Appendix B. Document Change Log 1837 [RFC Editor: Please delete this section on publication as RFC.] 1839 B.1. Changes to draft-ietf-lisp-rfc6830bis-27 1841 o Posted November 2019. 1843 o Fixed how LSB behave in the presence of new/removed locators. 1845 o Added ETR synchronization requirements when using Map-Versioning. 1847 o Fixed a large set of minor comments and edits. 1849 B.2. Changes to draft-ietf-lisp-rfc6830bis-27 1851 o Posted April 2019 post telechat. 1853 o Made editorial corrections per Warren's suggestions. 1855 o Put in suggested text from Luigi that Mirja agreed with. 1857 o LSB, Echo-Nonce and Map-Versioning SHOULD be only used in closed 1858 environments. 1860 o Removed paragraph stating that Instance-ID can be 32-bit in the 1861 control-plane. 1863 o 6831/8378 are now normative. 1865 o Rewritten Security Considerations according to the changes. 1867 o Stated that LSB SHOULD be coupled with Map-Versioning. 1869 B.3. Changes to draft-ietf-lisp-rfc6830bis-26 1871 o Posted late October 2018. 1873 o Changed description about "reserved" bits to state "reserved and 1874 unassigned". 1876 B.4. Changes to draft-ietf-lisp-rfc6830bis-25 1878 o Posted mid October 2018. 1880 o Added more to the Security Considerations section with discussion 1881 about echo-nonce attacks. 1883 B.5. Changes to draft-ietf-lisp-rfc6830bis-24 1885 o Posted mid October 2018. 1887 o Final editorial changes for Eric and Ben. 1889 B.6. Changes to draft-ietf-lisp-rfc6830bis-23 1891 o Posted early October 2018. 1893 o Added an applicability statement in section 1 to address security 1894 concerns from Telechat. 1896 B.7. Changes to draft-ietf-lisp-rfc6830bis-22 1898 o Posted early October 2018. 1900 o Changes to reflect comments post Telechat. 1902 B.8. Changes to draft-ietf-lisp-rfc6830bis-21 1904 o Posted late-September 2018. 1906 o Changes to reflect comments from Sep 27th Telechat. 1908 B.9. Changes to draft-ietf-lisp-rfc6830bis-20 1910 o Posted late-September 2018. 1912 o Fix old reference to RFC3168, changed to RFC6040. 1914 B.10. Changes to draft-ietf-lisp-rfc6830bis-19 1916 o Posted late-September 2018. 1918 o More editorial changes. 1920 B.11. Changes to draft-ietf-lisp-rfc6830bis-18 1922 o Posted mid-September 2018. 1924 o Changes to reflect comments from Secdir review (Mirja). 1926 B.12. Changes to draft-ietf-lisp-rfc6830bis-17 1928 o Posted September 2018. 1930 o Indicate in the "Changes since RFC 6830" section why the document 1931 has been shortened in length. 1933 o Make reference to RFC 8085 about UDP congestion control. 1935 o More editorial changes from multiple IESG reviews. 1937 B.13. Changes to draft-ietf-lisp-rfc6830bis-16 1939 o Posted late August 2018. 1941 o Distinguish the message type names between ICMP for IPv4 and ICMP 1942 for IPv6 for handling MTU issues. 1944 B.14. Changes to draft-ietf-lisp-rfc6830bis-15 1946 o Posted August 2018. 1948 o Final editorial changes before RFC submission for Proposed 1949 Standard. 1951 o Added section "Changes since RFC 6830" so implementers are 1952 informed of any changes since the last RFC publication. 1954 B.15. Changes to draft-ietf-lisp-rfc6830bis-14 1956 o Posted July 2018 IETF week. 1958 o Put obsolete of RFC 6830 in Intro section in addition to abstract. 1960 B.16. Changes to draft-ietf-lisp-rfc6830bis-13 1962 o Posted March IETF Week 2018. 1964 o Clarified that a new nonce is required per RLOC. 1966 o Removed 'Clock Sweep' section. This text must be placed in a new 1967 OAM document. 1969 o Some references changed from normative to informative 1971 B.17. Changes to draft-ietf-lisp-rfc6830bis-12 1973 o Posted July 2018. 1975 o Fixed Luigi editorial comments to ready draft for RFC status. 1977 B.18. Changes to draft-ietf-lisp-rfc6830bis-11 1979 o Posted March 2018. 1981 o Removed sections 16, 17 and 18 (Mobility, Deployment and 1982 Traceroute considerations). This text must be placed in a new OAM 1983 document. 1985 B.19. Changes to draft-ietf-lisp-rfc6830bis-10 1987 o Posted March 2018. 1989 o Updated section 'Router Locator Selection' stating that the Data- 1990 Plane MUST follow what's stored in the Map-Cache (priorities and 1991 weights). 1993 o Section 'Routing Locator Reachability': Removed bullet point 2 1994 (ICMP Network/Host Unreachable),3 (hints from BGP),4 (ICMP Port 1995 Unreachable),5 (receive a Map-Reply as a response) and RLOC 1996 probing 1998 o Removed 'Solicit-Map Request'. 2000 B.20. Changes to draft-ietf-lisp-rfc6830bis-09 2002 o Posted January 2018. 2004 o Add more details in section 5.3 about DSCP processing during 2005 encapsulation and decapsulation. 2007 o Added clarity to definitions in the Definition of Terms section 2008 from various commenters. 2010 o Removed PA and PI definitions from Definition of Terms section. 2012 o More editorial changes. 2014 o Removed 4342 from IANA section and move to RFC6833 IANA section. 2016 B.21. Changes to draft-ietf-lisp-rfc6830bis-08 2018 o Posted January 2018. 2020 o Remove references to research work for any protocol mechanisms. 2022 o Document scanned to make sure it is RFC 2119 compliant. 2024 o Made changes to reflect comments from document WG shepherd Luigi 2025 Iannone. 2027 o Ran IDNITs on the document. 2029 B.22. Changes to draft-ietf-lisp-rfc6830bis-07 2031 o Posted November 2017. 2033 o Rephrase how Instance-IDs are used and don't refer to [RFC1918] 2034 addresses. 2036 B.23. Changes to draft-ietf-lisp-rfc6830bis-06 2038 o Posted October 2017. 2040 o Put RTR definition before it is used. 2042 o Rename references that are now working group drafts. 2044 o Remove "EIDs MUST NOT be used as used by a host to refer to other 2045 hosts. Note that EID blocks MAY LISP RLOCs". 2047 o Indicate what address-family can appear in data packets. 2049 o ETRs may, rather than will, be the ones to send Map-Replies. 2051 o Recommend, rather than mandate, max encapsulation headers to 2. 2053 o Reference VPN draft when introducing Instance-ID. 2055 o Indicate that SMRs can be sent when ITR/ETR are in the same node. 2057 o Clarify when private addresses can be used. 2059 B.24. Changes to draft-ietf-lisp-rfc6830bis-05 2061 o Posted August 2017. 2063 o Make it clear that a Re-encapsulating Tunnel Router is an RTR. 2065 B.25. Changes to draft-ietf-lisp-rfc6830bis-04 2067 o Posted July 2017. 2069 o Changed reference of IPv6 RFC2460 to RFC8200. 2071 o Indicate that the applicability statement for UDP zero checksums 2072 over IPv6 adheres to RFC6936. 2074 B.26. Changes to draft-ietf-lisp-rfc6830bis-03 2076 o Posted May 2017. 2078 o Move the control-plane related codepoints in the IANA 2079 Considerations section to RFC6833bis. 2081 B.27. Changes to draft-ietf-lisp-rfc6830bis-02 2083 o Posted April 2017. 2085 o Reflect some editorial comments from Damien Sausez. 2087 B.28. Changes to draft-ietf-lisp-rfc6830bis-01 2089 o Posted March 2017. 2091 o Include references to new RFCs published. 2093 o Change references from RFC6833 to RFC6833bis. 2095 o Clarified LCAF text in the IANA section. 2097 o Remove references to "experimental". 2099 B.29. Changes to draft-ietf-lisp-rfc6830bis-00 2101 o Posted December 2016. 2103 o Created working group document from draft-farinacci-lisp 2104 -rfc6830-00 individual submission. No other changes made. 2106 Authors' Addresses 2108 Dino Farinacci 2109 lispers.net 2111 EMail: farinacci@gmail.com 2112 Vince Fuller 2113 vaf.net Internet Consulting 2115 EMail: vince.fuller@gmail.com 2117 Dave Meyer 2118 1-4-5.net 2120 EMail: dmm@1-4-5.net 2122 Darrel Lewis 2123 Cisco Systems 2124 170 Tasman Drive 2125 San Jose, CA 2126 USA 2128 EMail: darlewis@cisco.com 2130 Albert Cabellos 2131 UPC/BarcelonaTech 2132 Campus Nord, C. Jordi Girona 1-3 2133 Barcelona, Catalunya 2134 Spain 2136 EMail: acabello@ac.upc.edu