idnits 2.17.1 draft-ietf-lisp-rfc6830bis-21.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 (September 27, 2018) is 2038 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in RFCs) == Unused Reference: 'RFC7833' is defined on line 1704, but no explicit reference was found in the text == Outdated reference: A later version (-14) exists of draft-ietf-lisp-6834bis-02 == Outdated reference: A later version (-31) exists of draft-ietf-lisp-rfc6833bis-16 == Outdated reference: A later version (-15) exists of draft-ietf-lisp-introduction-13 == Outdated reference: A later version (-12) exists of draft-ietf-lisp-vpn-02 Summary: 0 errors (**), 0 flaws (~~), 6 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group D. Farinacci 3 Internet-Draft V. Fuller 4 Obsoletes: 6830 (if approved) D. Meyer 5 Intended status: Standards Track D. Lewis 6 Expires: March 31, 2019 Cisco Systems 7 A. Cabellos (Ed.) 8 UPC/BarcelonaTech 9 September 27, 2018 11 The Locator/ID Separation Protocol (LISP) 12 draft-ietf-lisp-rfc6830bis-21 14 Abstract 16 This document describes the Data-Plane protocol for the Locator/ID 17 Separation Protocol (LISP). LISP defines two namespaces, End-point 18 Identifiers (EIDs) that identify end-hosts and Routing Locators 19 (RLOCs) that identify network attachment points. With this, LISP 20 effectively separates control from data, and allows routers to create 21 overlay networks. LISP-capable routers exchange encapsulated packets 22 according to EID-to-RLOC mappings stored in a local Map-Cache. 24 LISP requires no change to either host protocol stacks or to underlay 25 routers and offers Traffic Engineering, multihoming and mobility, 26 among other features. 28 This document obsoletes RFC 6830. 30 Status of This Memo 32 This Internet-Draft is submitted in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF). Note that other groups may also distribute 37 working documents as Internet-Drafts. The list of current Internet- 38 Drafts is at https://datatracker.ietf.org/drafts/current/. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 This Internet-Draft will expire on March 31, 2019. 47 Copyright Notice 49 Copyright (c) 2018 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (https://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 65 2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 4 66 3. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 4 67 4. Basic Overview . . . . . . . . . . . . . . . . . . . . . . . 8 68 4.1. Packet Flow Sequence . . . . . . . . . . . . . . . . . . 10 69 5. LISP Encapsulation Details . . . . . . . . . . . . . . . . . 12 70 5.1. LISP IPv4-in-IPv4 Header Format . . . . . . . . . . . . . 13 71 5.2. LISP IPv6-in-IPv6 Header Format . . . . . . . . . . . . . 14 72 5.3. Tunnel Header Field Descriptions . . . . . . . . . . . . 15 73 6. LISP EID-to-RLOC Map-Cache . . . . . . . . . . . . . . . . . 20 74 7. Dealing with Large Encapsulated Packets . . . . . . . . . . . 20 75 7.1. A Stateless Solution to MTU Handling . . . . . . . . . . 21 76 7.2. A Stateful Solution to MTU Handling . . . . . . . . . . . 22 77 8. Using Virtualization and Segmentation with LISP . . . . . . . 22 78 9. Routing Locator Selection . . . . . . . . . . . . . . . . . . 23 79 10. Routing Locator Reachability . . . . . . . . . . . . . . . . 25 80 10.1. Echo Nonce Algorithm . . . . . . . . . . . . . . . . . . 26 81 11. EID Reachability within a LISP Site . . . . . . . . . . . . . 27 82 12. Routing Locator Hashing . . . . . . . . . . . . . . . . . . . 28 83 13. Changing the Contents of EID-to-RLOC Mappings . . . . . . . . 29 84 13.1. Database Map-Versioning . . . . . . . . . . . . . . . . 30 85 14. Multicast Considerations . . . . . . . . . . . . . . . . . . 31 86 15. Router Performance Considerations . . . . . . . . . . . . . . 31 87 16. Security Considerations . . . . . . . . . . . . . . . . . . . 32 88 17. Network Management Considerations . . . . . . . . . . . . . . 33 89 18. Changes since RFC 6830 . . . . . . . . . . . . . . . . . . . 33 90 19. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33 91 19.1. LISP UDP Port Numbers . . . . . . . . . . . . . . . . . 34 92 20. References . . . . . . . . . . . . . . . . . . . . . . . . . 34 93 20.1. Normative References . . . . . . . . . . . . . . . . . . 34 94 20.2. Informative References . . . . . . . . . . . . . . . . . 35 96 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 39 97 Appendix B. Document Change Log . . . . . . . . . . . . . . . . 39 98 B.1. Changes to draft-ietf-lisp-rfc6830bis-21 . . . . . . . . 40 99 B.2. Changes to draft-ietf-lisp-rfc6830bis-20 . . . . . . . . 40 100 B.3. Changes to draft-ietf-lisp-rfc6830bis-19 . . . . . . . . 40 101 B.4. Changes to draft-ietf-lisp-rfc6830bis-18 . . . . . . . . 40 102 B.5. Changes to draft-ietf-lisp-rfc6830bis-17 . . . . . . . . 40 103 B.6. Changes to draft-ietf-lisp-rfc6830bis-16 . . . . . . . . 40 104 B.7. Changes to draft-ietf-lisp-rfc6830bis-15 . . . . . . . . 40 105 B.8. Changes to draft-ietf-lisp-rfc6830bis-14 . . . . . . . . 41 106 B.9. Changes to draft-ietf-lisp-rfc6830bis-13 . . . . . . . . 41 107 B.10. Changes to draft-ietf-lisp-rfc6830bis-12 . . . . . . . . 41 108 B.11. Changes to draft-ietf-lisp-rfc6830bis-11 . . . . . . . . 41 109 B.12. Changes to draft-ietf-lisp-rfc6830bis-10 . . . . . . . . 41 110 B.13. Changes to draft-ietf-lisp-rfc6830bis-09 . . . . . . . . 42 111 B.14. Changes to draft-ietf-lisp-rfc6830bis-08 . . . . . . . . 42 112 B.15. Changes to draft-ietf-lisp-rfc6830bis-07 . . . . . . . . 42 113 B.16. Changes to draft-ietf-lisp-rfc6830bis-06 . . . . . . . . 42 114 B.17. Changes to draft-ietf-lisp-rfc6830bis-05 . . . . . . . . 43 115 B.18. Changes to draft-ietf-lisp-rfc6830bis-04 . . . . . . . . 43 116 B.19. Changes to draft-ietf-lisp-rfc6830bis-03 . . . . . . . . 43 117 B.20. Changes to draft-ietf-lisp-rfc6830bis-02 . . . . . . . . 43 118 B.21. Changes to draft-ietf-lisp-rfc6830bis-01 . . . . . . . . 43 119 B.22. Changes to draft-ietf-lisp-rfc6830bis-00 . . . . . . . . 44 120 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 44 122 1. Introduction 124 This document describes the Locator/Identifier Separation Protocol 125 (LISP). LISP is an encapsulation protocol built around the 126 fundamental idea of separating the topological location of a network 127 attachment point from the node's identity [CHIAPPA]. As a result 128 LISP creates two namespaces: Endpoint Identifiers (EIDs), that are 129 used to identify end-hosts (e.g., nodes or Virtual Machines) and 130 routable Routing Locators (RLOCs), used to identify network 131 attachment points. LISP then defines functions for mapping between 132 the two namespaces and for encapsulating traffic originated by 133 devices using non-routable EIDs for transport across a network 134 infrastructure that routes and forwards using RLOCs. LISP 135 encapsulation uses a dynamic form of tunneling where no static 136 provisioning is required or necessary. 138 LISP is an overlay protocol that separates control from Data-Plane, 139 this document specifies the Data-Plane, how LISP-capable routers 140 (Tunnel Routers) exchange packets by encapsulating them to the 141 appropriate location. Tunnel routers are equipped with a cache, 142 called Map-Cache, that contains EID-to-RLOC mappings. The Map-Cache 143 is populated using the LISP Control-Plane protocol 144 [I-D.ietf-lisp-rfc6833bis]. 146 LISP does not require changes to either host protocol stack or to 147 underlay routers. By separating the EID from the RLOC space, LISP 148 offers native Traffic Engineering, multihoming and mobility, among 149 other features. 151 Creation of LISP was initially motivated by discussions during the 152 IAB-sponsored Routing and Addressing Workshop held in Amsterdam in 153 October 2006 (see [RFC4984]). 155 This document specifies the LISP Data-Plane encapsulation and other 156 LISP forwarding node functionality while [I-D.ietf-lisp-rfc6833bis] 157 specifies the LISP control plane. LISP deployment guidelines can be 158 found in [RFC7215] and [RFC6835] describes considerations for network 159 operational management. Finally, [I-D.ietf-lisp-introduction] 160 describes the LISP architecture. 162 This document obsoletes RFC 6830. 164 2. Requirements Notation 166 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 167 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 168 document are to be interpreted as described in [RFC2119] and 169 [RFC8174]. 171 3. Definition of Terms 173 Address Family Identifier (AFI): AFI is a term used to describe an 174 address encoding in a packet. An address family that pertains to 175 addresses found in Data-Plane headers. See [AFN] and [RFC3232] 176 for details. An AFI value of 0 used in this specification 177 indicates an unspecified encoded address where the length of the 178 address is 0 octets following the 16-bit AFI value of 0. 180 Anycast Address: Anycast Address is a term used in this document to 181 refer to the same IPv4 or IPv6 address configured and used on 182 multiple systems at the same time. An EID or RLOC can be an 183 anycast address in each of their own address spaces. 185 Client-side: Client-side is a term used in this document to indicate 186 a connection initiation attempt by an end-system represented by an 187 EID. 189 Data-Probe: A Data-Probe is a LISP-encapsulated data packet where 190 the inner-header destination address equals the outer-header 191 destination address used to trigger a Map-Reply by a decapsulating 192 ETR. In addition, the original packet is decapsulated and 193 delivered to the destination host if the destination EID is in the 194 EID-Prefix range configured on the ETR. Otherwise, the packet is 195 discarded. A Data-Probe is used in some of the mapping database 196 designs to "probe" or request a Map-Reply from an ETR; in other 197 cases, Map-Requests are used. See each mapping database design 198 for details. When using Data-Probes, by sending Map-Requests on 199 the underlying routing system, EID-Prefixes must be advertised. 201 Egress Tunnel Router (ETR): An ETR is a router that accepts an IP 202 packet where the destination address in the "outer" IP header is 203 one of its own RLOCs. The router strips the "outer" header and 204 forwards the packet based on the next IP header found. In 205 general, an ETR receives LISP-encapsulated IP packets from the 206 Internet on one side and sends decapsulated IP packets to site 207 end-systems on the other side. ETR functionality does not have to 208 be limited to a router device. A server host can be the endpoint 209 of a LISP tunnel as well. 211 EID-to-RLOC Database: The EID-to-RLOC Database is a global 212 distributed database that contains all known EID-Prefix-to-RLOC 213 mappings. Each potential ETR typically contains a small piece of 214 the database: the EID-to-RLOC mappings for the EID-Prefixes 215 "behind" the router. These map to one of the router's own 216 globally visible IP addresses. Note that there MAY be transient 217 conditions when the EID-Prefix for the site and Locator-Set for 218 each EID-Prefix may not be the same on all ETRs. This has no 219 negative implications, since a partial set of Locators can be 220 used. 222 EID-to-RLOC Map-Cache: The EID-to-RLOC Map-Cache is generally 223 short-lived, on-demand table in an ITR that stores, tracks, and is 224 responsible for timing out and otherwise validating EID-to-RLOC 225 mappings. This cache is distinct from the full "database" of EID- 226 to-RLOC mappings; it is dynamic, local to the ITR(s), and 227 relatively small, while the database is distributed, relatively 228 static, and much more global in scope. 230 EID-Prefix: An EID-Prefix is a power-of-two block of EIDs that are 231 allocated to a site by an address allocation authority. EID- 232 Prefixes are associated with a set of RLOC addresses. EID-Prefix 233 allocations can be broken up into smaller blocks when an RLOC set 234 is to be associated with the larger EID-Prefix block. 236 End-System: An end-system is an IPv4 or IPv6 device that originates 237 packets with a single IPv4 or IPv6 header. The end-system 238 supplies an EID value for the destination address field of the IP 239 header when communicating globally (i.e., outside of its routing 240 domain). An end-system can be a host computer, a switch or router 241 device, or any network appliance. 243 Endpoint ID (EID): An EID is a 32-bit (for IPv4) or 128-bit (for 244 IPv6) value used in the source and destination address fields of 245 the first (most inner) LISP header of a packet. The host obtains 246 a destination EID the same way it obtains a destination address 247 today, for example, through a Domain Name System (DNS) [RFC1034] 248 lookup or Session Initiation Protocol (SIP) [RFC3261] exchange. 249 The source EID is obtained via existing mechanisms used to set a 250 host's "local" IP address. An EID used on the public Internet 251 MUST have the same properties as any other IP address used in that 252 manner; this means, among other things, that it MUST be globally 253 unique. An EID is allocated to a host from an EID-Prefix block 254 associated with the site where the host is located. An EID can be 255 used by a host to refer to other hosts. Note that EID blocks MAY 256 be assigned in a hierarchical manner, independent of the network 257 topology, to facilitate scaling of the mapping database. In 258 addition, an EID block assigned to a site MAY have site-local 259 structure (subnetting) for routing within the site; this structure 260 is not visible to the global routing system. In theory, the bit 261 string that represents an EID for one device can represent an RLOC 262 for a different device. When used in discussions with other 263 Locator/ID separation proposals, a LISP EID will be called an 264 "LEID". Throughout this document, any references to "EID" refer 265 to an LEID. 267 Ingress Tunnel Router (ITR): An ITR is a router that resides in a 268 LISP site. Packets sent by sources inside of the LISP site to 269 destinations outside of the site are candidates for encapsulation 270 by the ITR. The ITR treats the IP destination address as an EID 271 and performs an EID-to-RLOC mapping lookup. The router then 272 prepends an "outer" IP header with one of its routable RLOCs (in 273 the RLOC space) in the source address field and the result of the 274 mapping lookup in the destination address field. Note that this 275 destination RLOC may be an intermediate, proxy device that has 276 better knowledge of the EID-to-RLOC mapping closer to the 277 destination EID. In general, an ITR receives IP packets from site 278 end-systems on one side and sends LISP-encapsulated IP packets 279 toward the Internet on the other side. 281 Specifically, when a service provider prepends a LISP header for 282 Traffic Engineering purposes, the router that does this is also 283 regarded as an ITR. The outer RLOC the ISP ITR uses can be based 284 on the outer destination address (the originating ITR's supplied 285 RLOC) or the inner destination address (the originating host's 286 supplied EID). 288 LISP Header: LISP header is a term used in this document to refer 289 to the outer IPv4 or IPv6 header, a UDP header, and a LISP- 290 specific 8-octet header that follow the UDP header and that an ITR 291 prepends or an ETR strips. 293 LISP Router: A LISP router is a router that performs the functions 294 of any or all of the following: ITR, ETR, RTR, Proxy-ITR (PITR), 295 or Proxy-ETR (PETR). 297 LISP Site: LISP site is a set of routers in an edge network that are 298 under a single technical administration. LISP routers that reside 299 in the edge network are the demarcation points to separate the 300 edge network from the core network. 302 Locator-Status-Bits (LSBs): Locator-Status-Bits are present in the 303 LISP header. They are used by ITRs to inform ETRs about the up/ 304 down status of all ETRs at the local site. These bits are used as 305 a hint to convey up/down router status and not path reachability 306 status. The LSBs can be verified by use of one of the Locator 307 reachability algorithms described in Section 10. 309 Negative Mapping Entry: A negative mapping entry, also known as a 310 negative cache entry, is an EID-to-RLOC entry where an EID-Prefix 311 is advertised or stored with no RLOCs. That is, the Locator-Set 312 for the EID-to-RLOC entry is empty, one with an encoded Locator 313 count of 0. This type of entry could be used to describe a prefix 314 from a non-LISP site, which is explicitly not in the mapping 315 database. There are a set of well-defined actions that are 316 encoded in a Negative Map-Reply. 318 Proxy-ETR (PETR): A PETR is defined and described in [RFC6832]. A 319 PETR acts like an ETR but does so on behalf of LISP sites that 320 send packets to destinations at non-LISP sites. 322 Proxy-ITR (PITR): A PITR is defined and described in [RFC6832]. A 323 PITR acts like an ITR but does so on behalf of non-LISP sites that 324 send packets to destinations at LISP sites. 326 Recursive Tunneling: Recursive Tunneling occurs when a packet has 327 more than one LISP IP header. Additional layers of tunneling MAY 328 be employed to implement Traffic Engineering or other re-routing 329 as needed. When this is done, an additional "outer" LISP header 330 is added, and the original RLOCs are preserved in the "inner" 331 header. 333 Re-Encapsulating Tunneling Router (RTR): An RTR acts like an ETR to 334 remove a LISP header, then acts as an ITR to prepend a new LISP 335 header. This is known as Re-encapsulating Tunneling. Doing this 336 allows a packet to be re-routed by the RTR without adding the 337 overhead of additional tunnel headers. When using multiple 338 mapping database systems, care must be taken to not create re- 339 encapsulation loops through misconfiguration. 341 Route-Returnability: Route-returnability is an assumption that the 342 underlying routing system will deliver packets to the destination. 343 When combined with a nonce that is provided by a sender and 344 returned by a receiver, this limits off-path data insertion. A 345 route-returnability check is verified when a message is sent with 346 a nonce, another message is returned with the same nonce, and the 347 destination of the original message appears as the source of the 348 returned message. 350 Routing Locator (RLOC): An RLOC is an IPv4 [RFC0791] or IPv6 351 [RFC8200] address of an Egress Tunnel Router (ETR). An RLOC is 352 the output of an EID-to-RLOC mapping lookup. An EID maps to zero 353 or more RLOCs. Typically, RLOCs are numbered from blocks that are 354 assigned to a site at each point to which it attaches to the 355 underlay network; where the topology is defined by the 356 connectivity of provider networks. Multiple RLOCs can be assigned 357 to the same ETR device or to multiple ETR devices at a site. 359 Server-side: Server-side is a term used in this document to indicate 360 that a connection initiation attempt is being accepted for a 361 destination EID. 363 TE-ETR: A TE-ETR is an ETR that is deployed in a service provider 364 network that strips an outer LISP header for Traffic Engineering 365 purposes. 367 TE-ITR: A TE-ITR is an ITR that is deployed in a service provider 368 network that prepends an additional LISP header for Traffic 369 Engineering purposes. 371 xTR: An xTR is a reference to an ITR or ETR when direction of data 372 flow is not part of the context description. "xTR" refers to the 373 router that is the tunnel endpoint and is used synonymously with 374 the term "Tunnel Router". For example, "An xTR can be located at 375 the Customer Edge (CE) router" indicates both ITR and ETR 376 functionality at the CE router. 378 4. Basic Overview 380 One key concept of LISP is that end-systems operate the same way they 381 do today. The IP addresses that hosts use for tracking sockets and 382 connections, and for sending and receiving packets, do not change. 384 In LISP terminology, these IP addresses are called Endpoint 385 Identifiers (EIDs). 387 Routers continue to forward packets based on IP destination 388 addresses. When a packet is LISP encapsulated, these addresses are 389 referred to as Routing Locators (RLOCs). Most routers along a path 390 between two hosts will not change; they continue to perform routing/ 391 forwarding lookups on the destination addresses. For routers between 392 the source host and the ITR as well as routers from the ETR to the 393 destination host, the destination address is an EID. For the routers 394 between the ITR and the ETR, the destination address is an RLOC. 396 Another key LISP concept is the "Tunnel Router". A Tunnel Router 397 prepends LISP headers on host-originated packets and strips them 398 prior to final delivery to their destination. The IP addresses in 399 this "outer header" are RLOCs. During end-to-end packet exchange 400 between two Internet hosts, an ITR prepends a new LISP header to each 401 packet, and an ETR strips the new header. The ITR performs EID-to- 402 RLOC lookups to determine the routing path to the ETR, which has the 403 RLOC as one of its IP addresses. 405 Some basic rules governing LISP are: 407 o End-systems only send to addresses that are EIDs. EIDs are 408 typically IP addresses assigned to hosts (other types of EID are 409 supported by LISP, see [RFC8060] for further information). End- 410 systems don't know that addresses are EIDs versus RLOCs but assume 411 that packets get to their intended destinations. In a system 412 where LISP is deployed, LISP routers intercept EID-addressed 413 packets and assist in delivering them across the network core 414 where EIDs cannot be routed. The procedure a host uses to send IP 415 packets does not change. 417 o LISP routers mostly deal with Routing Locator addresses. See 418 details in Section 4.1 to clarify what is meant by "mostly". 420 o RLOCs are always IP addresses assigned to routers, preferably 421 topologically oriented addresses from provider CIDR (Classless 422 Inter-Domain Routing) blocks. 424 o When a router originates packets, it MAY use as a source address 425 either an EID or RLOC. When acting as a host (e.g., when 426 terminating a transport session such as Secure SHell (SSH), 427 TELNET, or the Simple Network Management Protocol (SNMP)), it MAY 428 use an EID that is explicitly assigned for that purpose. An EID 429 that identifies the router as a host MUST NOT be used as an RLOC; 430 an EID is only routable within the scope of a site. A typical BGP 431 configuration might demonstrate this "hybrid" EID/RLOC usage where 432 a router could use its "host-like" EID to terminate iBGP sessions 433 to other routers in a site while at the same time using RLOCs to 434 terminate eBGP sessions to routers outside the site. 436 o Packets with EIDs in them are not expected to be delivered end-to- 437 end in the absence of an EID-to-RLOC mapping operation. They are 438 expected to be used locally for intra-site communication or to be 439 encapsulated for inter-site communication. 441 o EIDs MAY also be structured (subnetted) in a manner suitable for 442 local routing within an Autonomous System (AS). 444 An additional LISP header MAY be prepended to packets by a TE-ITR 445 when re-routing of the path for a packet is desired. A potential 446 use-case for this would be an ISP router that needs to perform 447 Traffic Engineering for packets flowing through its network. In such 448 a situation, termed "Recursive Tunneling", an ISP transit acts as an 449 additional ITR, and the destination RLOC it uses for the new 450 prepended header would be either a TE-ETR within the ISP (along an 451 intra-ISP traffic engineered path) or a TE-ETR within another ISP (an 452 inter-ISP traffic engineered path, where an agreement to build such a 453 path exists). 455 In order to avoid excessive packet overhead as well as possible 456 encapsulation loops, this document recommends that a maximum of two 457 LISP headers can be prepended to a packet. For initial LISP 458 deployments, it is assumed that two headers is sufficient, where the 459 first prepended header is used at a site for Location/Identity 460 separation and the second prepended header is used inside a service 461 provider for Traffic Engineering purposes. 463 Tunnel Routers can be placed fairly flexibly in a multi-AS topology. 464 For example, the ITR for a particular end-to-end packet exchange 465 might be the first-hop or default router within a site for the source 466 host. Similarly, the ETR might be the last-hop router directly 467 connected to the destination host. Another example, perhaps for a 468 VPN service outsourced to an ISP by a site, the ITR could be the 469 site's border router at the service provider attachment point. 470 Mixing and matching of site-operated, ISP-operated, and other Tunnel 471 Routers is allowed for maximum flexibility. 473 4.1. Packet Flow Sequence 475 This section provides an example of the unicast packet flow, 476 including also Control-Plane information as specified in 477 [I-D.ietf-lisp-rfc6833bis]. The example also assumes the following 478 conditions: 480 o Source host "host1.abc.example.com" is sending a packet to 481 "host2.xyz.example.com", exactly what host1 would do if the site 482 was not using LISP. 484 o Each site is multihomed, so each Tunnel Router has an address 485 (RLOC) assigned from the service provider address block for each 486 provider to which that particular Tunnel Router is attached. 488 o The ITR(s) and ETR(s) are directly connected to the source and 489 destination, respectively, but the source and destination can be 490 located anywhere in the LISP site. 492 o A Map-Request is sent for an external destination when the 493 destination is not found in the forwarding table or matches a 494 default route. Map-Requests are sent to the mapping database 495 system by using the LISP Control-Plane protocol documented in 496 [I-D.ietf-lisp-rfc6833bis]. 498 o Map-Replies are sent on the underlying routing system topology 499 using the [I-D.ietf-lisp-rfc6833bis] Control-Plane protocol. 501 Client host1.abc.example.com wants to communicate with server 502 host2.xyz.example.com: 504 1. host1.abc.example.com wants to open a TCP connection to 505 host2.xyz.example.com. It does a DNS lookup on 506 host2.xyz.example.com. An A/AAAA record is returned. This 507 address is the destination EID. The locally assigned address of 508 host1.abc.example.com is used as the source EID. An IPv4 or IPv6 509 packet is built and forwarded through the LISP site as a normal 510 IP packet until it reaches a LISP ITR. 512 2. The LISP ITR must be able to map the destination EID to an RLOC 513 of one of the ETRs at the destination site. The specific method 514 used to do this is not described in this example. See 515 [I-D.ietf-lisp-rfc6833bis] for further information. 517 3. The ITR sends a LISP Map-Request as specified in 518 [I-D.ietf-lisp-rfc6833bis]. Map-Requests SHOULD be rate-limited. 520 4. The mapping system helps forwarding the Map-Request to the 521 corresponding ETR. When the Map-Request arrives at one of the 522 ETRs at the destination site, it will process the packet as a 523 control message. 525 5. The ETR looks at the destination EID of the Map-Request and 526 matches it against the prefixes in the ETR's configured EID-to- 527 RLOC mapping database. This is the list of EID-Prefixes the ETR 528 is supporting for the site it resides in. If there is no match, 529 the Map-Request is dropped. Otherwise, a LISP Map-Reply is 530 returned to the ITR. 532 6. The ITR receives the Map-Reply message, parses the message (to 533 check for format validity), and stores the mapping information 534 from the packet. This information is stored in the ITR's EID-to- 535 RLOC Map-Cache. Note that the Map-Cache is an on-demand cache. 536 An ITR will manage its Map-Cache in such a way that optimizes for 537 its resource constraints. 539 7. Subsequent packets from host1.abc.example.com to 540 host2.xyz.example.com will have a LISP header prepended by the 541 ITR using the appropriate RLOC as the LISP header destination 542 address learned from the ETR. Note that the packet MAY be sent 543 to a different ETR than the one that returned the Map-Reply due 544 to the source site's hashing policy or the destination site's 545 Locator-Set policy. 547 8. The ETR receives these packets directly (since the destination 548 address is one of its assigned IP addresses), checks the validity 549 of the addresses, strips the LISP header, and forwards packets to 550 the attached destination host. 552 9. In order to defer the need for a mapping lookup in the reverse 553 direction, an ETR can OPTIONALLY create a cache entry that maps 554 the source EID (inner-header source IP address) to the source 555 RLOC (outer-header source IP address) in a received LISP packet. 556 Such a cache entry is termed a "glean mapping" and only contains 557 a single RLOC for the EID in question. More complete information 558 about additional RLOCs SHOULD be verified by sending a LISP Map- 559 Request for that EID. Both the ITR and the ETR MAY also 560 influence the decision the other makes in selecting an RLOC. 562 5. LISP Encapsulation Details 564 Since additional tunnel headers are prepended, the packet becomes 565 larger and can exceed the MTU of any link traversed from the ITR to 566 the ETR. It is RECOMMENDED in IPv4 that packets do not get 567 fragmented as they are encapsulated by the ITR. Instead, the packet 568 is dropped and an ICMP Unreachable/Fragmentation-Needed message is 569 returned to the source. 571 In the case when fragmentation is needed, this specification 572 RECOMMENDS that implementations provide support for one of the 573 proposed fragmentation and reassembly schemes. Two existing schemes 574 are detailed in Section 7. 576 Since IPv4 or IPv6 addresses can be either EIDs or RLOCs, the LISP 577 architecture supports IPv4 EIDs with IPv6 RLOCs (where the inner 578 header is in IPv4 packet format and the outer header is in IPv6 579 packet format) or IPv6 EIDs with IPv4 RLOCs (where the inner header 580 is in IPv6 packet format and the outer header is in IPv4 packet 581 format). The next sub-sections illustrate packet formats for the 582 homogeneous case (IPv4-in-IPv4 and IPv6-in-IPv6), but all 4 583 combinations MUST be supported. Additional types of EIDs are defined 584 in [RFC8060]. 586 As LISP uses UDP encapsulation to carry traffic between xTRs across 587 the Internet, implementors should be aware of the provisions of 588 [RFC8085], especially those given in section 3.1.11 on congestion 589 control for UDP tunneling. 591 Implementors are encouraged to consider UDP checksum usage guidelines 592 in section 3.4 of [RFC8085] when it is desirable to protect UDP and 593 LISP headers against corruption. 595 5.1. LISP IPv4-in-IPv4 Header Format 596 0 1 2 3 597 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 1 598 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 599 / |Version| IHL | DSCP |ECN| Total Length | 600 / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 601 | | Identification |Flags| Fragment Offset | 602 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 603 OH | Time to Live | Protocol = 17 | Header Checksum | 604 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 605 | | Source Routing Locator | 606 \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 607 \ | Destination Routing Locator | 608 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 609 / | Source Port = xxxx | Dest Port = 4341 | 610 UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 611 \ | UDP Length | UDP Checksum | 612 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 613 L |N|L|E|V|I|R|K|K| Nonce/Map-Version | 614 I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 615 S / | Instance ID/Locator-Status-Bits | 616 P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 617 / |Version| IHL | DSCP |ECN| Total Length | 618 / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 619 | | Identification |Flags| Fragment Offset | 620 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 621 IH | Time to Live | Protocol | Header Checksum | 622 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 623 | | Source EID | 624 \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 625 \ | Destination EID | 626 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 628 IHL = IP-Header-Length 630 5.2. LISP IPv6-in-IPv6 Header Format 632 0 1 2 3 633 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 1 634 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 635 / |Version| DSCP |ECN| Flow Label | 636 / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 637 | | Payload Length | Next Header=17| Hop Limit | 638 v +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 639 | | 640 O + + 641 u | | 642 t + Source Routing Locator + 643 e | | 644 r + + 645 | | 646 H +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 647 d | | 648 r + + 649 | | 650 ^ + Destination Routing Locator + 651 | | | 652 \ + + 653 \ | | 654 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 655 / | Source Port = xxxx | Dest Port = 4341 | 656 UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 657 \ | UDP Length | UDP Checksum | 658 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 659 L |N|L|E|V|I|R|K|K| Nonce/Map-Version | 660 I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 661 S / | Instance ID/Locator-Status-Bits | 662 P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 663 / |Version| DSCP |ECN| Flow Label | 664 / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 665 / | Payload Length | Next Header | Hop Limit | 666 v +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 667 | | 668 I + + 669 n | | 670 n + Source EID + 671 e | | 672 r + + 673 | | 674 H +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 675 d | | 676 r + + 677 | | 678 ^ + Destination EID + 679 \ | | 680 \ + + 681 \ | | 682 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 684 5.3. Tunnel Header Field Descriptions 686 Inner Header (IH): The inner header is the header on the 687 datagram received from the originating host [RFC0791] [RFC8200] 688 [RFC2474]. The source and destination IP addresses are EIDs. 690 Outer Header: (OH) The outer header is a new header prepended by an 691 ITR. The address fields contain RLOCs obtained from the ingress 692 router's EID-to-RLOC Cache. The IP protocol number is "UDP (17)" 693 from [RFC0768]. The setting of the Don't Fragment (DF) bit 694 'Flags' field is according to rules listed in Sections 7.1 and 695 7.2. 697 UDP Header: The UDP header contains an ITR selected source port when 698 encapsulating a packet. See Section 12 for details on the hash 699 algorithm used to select a source port based on the 5-tuple of the 700 inner header. The destination port MUST be set to the well-known 701 IANA-assigned port value 4341. 703 UDP Checksum: The 'UDP Checksum' field SHOULD be transmitted as zero 704 by an ITR for either IPv4 [RFC0768] and IPv6 encapsulation 705 [RFC6935] [RFC6936]. When a packet with a zero UDP checksum is 706 received by an ETR, the ETR MUST accept the packet for 707 decapsulation. When an ITR transmits a non-zero value for the UDP 708 checksum, it MUST send a correctly computed value in this field. 709 When an ETR receives a packet with a non-zero UDP checksum, it MAY 710 choose to verify the checksum value. If it chooses to perform 711 such verification, and the verification fails, the packet MUST be 712 silently dropped. If the ETR chooses not to perform the 713 verification, or performs the verification successfully, the 714 packet MUST be accepted for decapsulation. The handling of UDP 715 zero checksums over IPv6 for all tunneling protocols, including 716 LISP, is subject to the applicability statement in [RFC6936]. 718 UDP Length: The 'UDP Length' field is set for an IPv4-encapsulated 719 packet to be the sum of the inner-header IPv4 Total Length plus 720 the UDP and LISP header lengths. For an IPv6-encapsulated packet, 721 the 'UDP Length' field is the sum of the inner-header IPv6 Payload 722 Length, the size of the IPv6 header (40 octets), and the size of 723 the UDP and LISP headers. 725 N: The N-bit is the nonce-present bit. When this bit is set to 1, 726 the low-order 24 bits of the first 32 bits of the LISP header 727 contain a Nonce. See Section 10.1 for details. Both N- and 728 V-bits MUST NOT be set in the same packet. If they are, a 729 decapsulating ETR MUST treat the 'Nonce/Map-Version' field as 730 having a Nonce value present. 732 L: The L-bit is the 'Locator-Status-Bits' field enabled bit. When 733 this bit is set to 1, the Locator-Status-Bits in the second 734 32 bits of the LISP header are in use. 736 x 1 x x 0 x x x 737 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 738 |N|L|E|V|I|R|K|K| Nonce/Map-Version | 739 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 740 | Locator-Status-Bits | 741 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 743 E: The E-bit is the echo-nonce-request bit. This bit MUST be ignored 744 and has no meaning when the N-bit is set to 0. When the N-bit is 745 set to 1 and this bit is set to 1, an ITR is requesting that the 746 nonce value in the 'Nonce' field be echoed back in LISP- 747 encapsulated packets when the ITR is also an ETR. See 748 Section 10.1 for details. 750 V: The V-bit is the Map-Version present bit. When this bit is set to 751 1, the N-bit MUST be 0. Refer to Section 13.1 for more details. 752 This bit indicates that the LISP header is encoded in this 753 case as: 755 0 x 0 1 x x x x 756 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 757 |N|L|E|V|I|R|K|K| Source Map-Version | Dest Map-Version | 758 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 759 | Instance ID/Locator-Status-Bits | 760 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 762 I: The I-bit is the Instance ID bit. See Section 8 for more details. 763 When this bit is set to 1, the 'Locator-Status-Bits' field is 764 reduced to 8 bits and the high-order 24 bits are used as an 765 Instance ID. If the L-bit is set to 0, then the low-order 8 bits 766 are transmitted as zero and ignored on receipt. The format of the 767 LISP header would look like this: 769 x x x x 1 x x x 770 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 771 |N|L|E|V|I|R|K|K| Nonce/Map-Version | 772 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 773 | Instance ID | LSBs | 774 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 776 R: The R-bit is a Reserved bit for future use. It MUST be set to 0 777 on transmit and MUST be ignored on receipt. 779 KK: The KK-bits are a 2-bit field used when encapsulated packets are 780 encrypted. The field is set to 00 when the packet is not 781 encrypted. See [RFC8061] for further information. 783 LISP Nonce: The LISP 'Nonce' field is a 24-bit value that is 784 randomly generated by an ITR when the N-bit is set to 1. Nonce 785 generation algorithms are an implementation matter but are 786 required to generate different nonces when sending to different 787 RLOCs. However, the same nonce can be used for a period of time 788 when encapsulating to the same ETR. The nonce is also used when 789 the E-bit is set to request the nonce value to be echoed by the 790 other side when packets are returned. When the E-bit is clear but 791 the N-bit is set, a remote ITR is either echoing a previously 792 requested echo-nonce or providing a random nonce. See 793 Section 10.1 for more details. 795 LISP Locator-Status-Bits (LSBs): When the L-bit is also set, the 796 'Locator-Status-Bits' field in the LISP header is set by an ITR to 797 indicate to an ETR the up/down status of the Locators in the 798 source site. Each RLOC in a Map-Reply is assigned an ordinal 799 value from 0 to n-1 (when there are n RLOCs in a mapping entry). 800 The Locator-Status-Bits are numbered from 0 to n-1 from the least 801 significant bit of the field. The field is 32 bits when the I-bit 802 is set to 0 and is 8 bits when the I-bit is set to 1. When a 803 Locator-Status-Bit is set to 1, the ITR is indicating to the ETR 804 that the RLOC associated with the bit ordinal has up status. See 805 Section 10 for details on how an ITR can determine the status of 806 the ETRs at the same site. When a site has multiple EID-Prefixes 807 that result in multiple mappings (where each could have a 808 different Locator-Set), the Locator-Status-Bits setting in an 809 encapsulated packet MUST reflect the mapping for the EID-Prefix 810 that the inner-header source EID address matches. If the LSB for 811 an anycast Locator is set to 1, then there is at least one RLOC 812 with that address, and the ETR is considered 'up'. 814 When doing ITR/PITR encapsulation: 816 o The outer-header 'Time to Live' field (or 'Hop Limit' field, in 817 the case of IPv6) SHOULD be copied from the inner-header 'Time to 818 Live' field. 820 o The outer-header 'Differentiated Services Code Point' (DSCP) field 821 (or the 'Traffic Class' field, in the case of IPv6) SHOULD be 822 copied from the inner-header DSCP field ('Traffic Class' field, in 823 the case of IPv6) to the outer-header. 825 o The 'Explicit Congestion Notification' (ECN) field (bits 6 and 7 826 of the IPv6 'Traffic Class' field) requires special treatment in 827 order to avoid discarding indications of congestion [RFC6040]. 828 ITR encapsulation MUST copy the 2-bit 'ECN' field from the inner 829 header to the outer header. Re-encapsulation MUST copy the 2-bit 830 'ECN' field from the stripped outer header to the new outer 831 header. 833 When doing ETR/PETR decapsulation: 835 o The inner-header 'Time to Live' field (or 'Hop Limit' field, in 836 the case of IPv6) MUST be copied from the outer-header 'Time to 837 Live' field, when the Time to Live value of the outer header is 838 less than the Time to Live value of the inner header. Failing to 839 perform this check can cause the Time to Live of the inner header 840 to increment across encapsulation/decapsulation cycles. This 841 check is also performed when doing initial encapsulation, when a 842 packet comes to an ITR or PITR destined for a LISP site. 844 o The outer-header 'Differentiated Services Code Point' (DSCP) field 845 (or the 'Traffic Class' field, in the case of IPv6) SHOULD be 846 copied from the outer-header DSCP field ('Traffic Class' field, in 847 the case of IPv6) to the inner-header. 849 o The 'Explicit Congestion Notification' (ECN) field (bits 6 and 7 850 of the IPv6 'Traffic Class' field) requires special treatment in 851 order to avoid discarding indications of congestion [RFC6040]. If 852 the 'ECN' field contains a congestion indication codepoint (the 853 value is '11', the Congestion Experienced (CE) codepoint), then 854 ETR decapsulation MUST copy the 2-bit 'ECN' field from the 855 stripped outer header to the surviving inner header that is used 856 to forward the packet beyond the ETR. These requirements preserve 857 CE indications when a packet that uses ECN traverses a LISP tunnel 858 and becomes marked with a CE indication due to congestion between 859 the tunnel endpoints. Implementations exist that copy the 'ECN' 860 field from the outer header to the inner header even though 861 [RFC6040] does not recommend this behavior. It is RECOMMENDED 862 that implementations change to support the behavior in [RFC6040]. 864 Note that if an ETR/PETR is also an ITR/PITR and chooses to re- 865 encapsulate after decapsulating, the net effect of this is that the 866 new outer header will carry the same Time to Live as the old outer 867 header minus 1. 869 Copying the Time to Live (TTL) serves two purposes: first, it 870 preserves the distance the host intended the packet to travel; 871 second, and more importantly, it provides for suppression of looping 872 packets in the event there is a loop of concatenated tunnels due to 873 misconfiguration. 875 The Explicit Congestion Notification ('ECN') field occupies bits 6 876 and 7 of both the IPv4 'Type of Service' field and the IPv6 'Traffic 877 Class' field [RFC6040]. The 'ECN' field requires special treatment 878 in order to avoid discarding indications of congestion [RFC6040]. An 879 ITR/PITR encapsulation MUST copy the 2-bit 'ECN' field from the inner 880 header to the outer header. Re-encapsulation MUST copy the 2-bit 881 'ECN' field from the stripped outer header to the new outer header. 882 If the 'ECN' field contains a congestion indication codepoint (the 883 value is '11', the Congestion Experienced (CE) codepoint), then ETR/ 884 PETR decapsulation MUST copy the 2-bit 'ECN' field from the stripped 885 outer header to the surviving inner header that is used to forward 886 the packet beyond the ETR. These requirements preserve CE 887 indications when a packet that uses ECN traverses a LISP tunnel and 888 becomes marked with a CE indication due to congestion between the 889 tunnel endpoints. 891 6. LISP EID-to-RLOC Map-Cache 893 ITRs and PITRs maintain an on-demand cache, referred as LISP EID-to- 894 RLOC Map-Cache, that contains mappings from EID-prefixes to locator 895 sets. The cache is used to encapsulate packets from the EID space to 896 the corresponding RLOC network attachment point. 898 When an ITR/PITR receives a packet from inside of the LISP site to 899 destinations outside of the site a longest-prefix match lookup of the 900 EID is done to the Map-Cache. 902 When the lookup succeeds, the Locator-Set retrieved from the Map- 903 Cache is used to send the packet to the EID's topological location. 905 If the lookup fails, the ITR/PITR needs to retrieve the mapping using 906 the LISP Control-Plane protocol [I-D.ietf-lisp-rfc6833bis]. The 907 mapping is then stored in the local Map-Cache to forward subsequent 908 packets addressed to the same EID-prefix. 910 The Map-Cache is a local cache of mappings, entries are expired based 911 on the associated Time to live. In addition, entries can be updated 912 with more current information, see Section 13 for further information 913 on this. Finally, the Map-Cache also contains reachability 914 information about EIDs and RLOCs, and uses LISP reachability 915 information mechanisms to determine the reachability of RLOCs, see 916 Section 10 for the specific mechanisms. 918 7. Dealing with Large Encapsulated Packets 920 This section proposes two mechanisms to deal with packets that exceed 921 the path MTU between the ITR and ETR. 923 It is left to the implementor to decide if the stateless or stateful 924 mechanism SHOULD be implemented. Both or neither can be used, since 925 it is a local decision in the ITR regarding how to deal with MTU 926 issues, and sites can interoperate with differing mechanisms. 928 Both stateless and stateful mechanisms also apply to Re-encapsulating 929 and Recursive Tunneling, so any actions below referring to an ITR 930 also apply to a TE-ITR. 932 7.1. A Stateless Solution to MTU Handling 934 An ITR stateless solution to handle MTU issues is described as 935 follows: 937 1. Define H to be the size, in octets, of the outer header an ITR 938 prepends to a packet. This includes the UDP and LISP header 939 lengths. 941 2. Define L to be the size, in octets, of the maximum-sized packet 942 an ITR can send to an ETR without the need for the ITR or any 943 intermediate routers to fragment the packet. 945 3. Define an architectural constant S for the maximum size of a 946 packet, in octets, an ITR MUST receive from the source so the 947 effective MTU can be met. That is, L = S + H. 949 When an ITR receives a packet from a site-facing interface and adds H 950 octets worth of encapsulation to yield a packet size greater than L 951 octets (meaning the received packet size was greater than S octets 952 from the source), it resolves the MTU issue by first splitting the 953 original packet into 2 equal-sized fragments. A LISP header is then 954 prepended to each fragment. The size of the encapsulated fragments 955 is then (S/2 + H), which is less than the ITR's estimate of the path 956 MTU between the ITR and its correspondent ETR. 958 When an ETR receives encapsulated fragments, it treats them as two 959 individually encapsulated packets. It strips the LISP headers and 960 then forwards each fragment to the destination host of the 961 destination site. The two fragments are reassembled at the 962 destination host into the single IP datagram that was originated by 963 the source host. Note that reassembly can happen at the ETR if the 964 encapsulated packet was fragmented at or after the ITR. 966 This behavior MUST be performed by the ITR only when the source host 967 originates a packet with the 'DF' field of the IP header set to 0. 968 When the 'DF' field of the IP header is set to 1, or the packet is an 969 IPv6 packet originated by the source host, the ITR will drop the 970 packet when the size is greater than L and send an ICMPv4 ICMP 971 Unreachable/Fragmentation-Needed or ICMPv6 "Packet Too Big" message 972 to the source with a value of S, where S is (L - H). 974 When the outer-header encapsulation uses an IPv4 header, an 975 implementation SHOULD set the DF bit to 1 so ETR fragment reassembly 976 can be avoided. An implementation MAY set the DF bit in such headers 977 to 0 if it has good reason to believe there are unresolvable path MTU 978 issues between the sending ITR and the receiving ETR. 980 This specification RECOMMENDS that L be defined as 1500. 982 7.2. A Stateful Solution to MTU Handling 984 An ITR stateful solution to handle MTU issues is described as follows 985 and was first introduced in [OPENLISP]: 987 1. The ITR will keep state of the effective MTU for each Locator per 988 Map-Cache entry. The effective MTU is what the core network can 989 deliver along the path between the ITR and ETR. 991 2. When an IPv6-encapsulated packet, or an IPv4-encapsulated packet 992 with the DF bit set to 1, exceeds what the core network can 993 deliver, one of the intermediate routers on the path will send an 994 ICMPv6 "Packet Too Big" message or an ICMPv4 Unreachable/ 995 Fragmentation-Needed to the ITR, respectively. The ITR will 996 parse the ICMP message to determine which Locator is affected by 997 the effective MTU change and then record the new effective MTU 998 value in the Map-Cache entry. 1000 3. When a packet is received by the ITR from a source inside of the 1001 site and the size of the packet is greater than the effective MTU 1002 stored with the Map-Cache entry associated with the destination 1003 EID the packet is for, the ITR will send an ICMPv4 ICMP 1004 Unreachable/Fragmentation-Needed or ICMPv6 "Packet Too Big" 1005 message back to the source. The packet size advertised by the 1006 ITR in the ICMP message is the effective MTU minus the LISP 1007 encapsulation length. 1009 Even though this mechanism is stateful, it has advantages over the 1010 stateless IP fragmentation mechanism, by not involving the 1011 destination host with reassembly of ITR fragmented packets. 1013 8. Using Virtualization and Segmentation with LISP 1015 There are several cases where segregation is needed at the EID level. 1016 For instance, this is the case for deployments containing overlapping 1017 addresses, traffic isolation policies or multi-tenant virtualization. 1018 For these and other scenarios where segregation is needed, Instance 1019 IDs are used. 1021 An Instance ID can be carried in a LISP-encapsulated packet. An ITR 1022 that prepends a LISP header will copy a 24-bit value used by the LISP 1023 router to uniquely identify the address space. The value is copied 1024 to the 'Instance ID' field of the LISP header, and the I-bit is set 1025 to 1. 1027 When an ETR decapsulates a packet, the Instance ID from the LISP 1028 header is used as a table identifier to locate the forwarding table 1029 to use for the inner destination EID lookup. 1031 For example, an 802.1Q VLAN tag or VPN identifier could be used as a 1032 24-bit Instance ID. See [I-D.ietf-lisp-vpn] for LISP VPN use-case 1033 details. 1035 The Instance ID that is stored in the mapping database when LISP-DDT 1036 [RFC8111] is used is 32 bits in length. That means the Control-Plane 1037 can store more instances than a given Data-Plane can use. Multiple 1038 Data-Planes can use the same 32-bit space as long as the low-order 24 1039 bits don't overlap among xTRs. 1041 9. Routing Locator Selection 1043 The Map-Cache contains the state used by ITRs and PITRs to 1044 encapsulate packets. When an ITR/PITR receives a packet from inside 1045 the LISP site to a destination outside of the site a longest-prefix 1046 match lookup of the EID is done to the Map-Cache (see Section 6). 1047 The lookup returns a single Locator-Set containing a list of RLOCs 1048 corresponding to the EID's topological location. Each RLOC in the 1049 Locator-Set is associated with a 'Priority' and 'Weight', this 1050 information is used to select the RLOC to encapsulate. 1052 The RLOC with the lowest 'Priority' is selected. An RLOC with 1053 'Priority' 255 means that MUST NOT be used for forwarding. When 1054 multiple RLOC have the same 'Priority' then the 'Weight' states how 1055 to load balance traffic among them. The value of the 'Weight' 1056 represents the relative weight of the total packets that match the 1057 maping entry. 1059 The following are different scenarios for choosing RLOCs and the 1060 controls that are available: 1062 o The server-side returns one RLOC. The client-side can only use 1063 one RLOC. The server-side has complete control of the selection. 1065 o The server-side returns a list of RLOCs where a subset of the list 1066 has the same best Priority. The client can only use the subset 1067 list according to the weighting assigned by the server-side. In 1068 this case, the server-side controls both the subset list and load- 1069 splitting across its members. The client-side can use RLOCs 1070 outside of the subset list if it determines that the subset list 1071 is unreachable (unless RLOCs are set to a Priority of 255). Some 1072 sharing of control exists: the server-side determines the 1073 destination RLOC list and load distribution while the client-side 1074 has the option of using alternatives to this list if RLOCs in the 1075 list are unreachable. 1077 o The server-side sets a Weight of zero for the RLOC subset list. 1078 In this case, the client-side can choose how the traffic load is 1079 spread across the subset list. Control is shared by the server- 1080 side determining the list and the client-side determining load 1081 distribution. Again, the client can use alternative RLOCs if the 1082 server-provided list of RLOCs is unreachable. 1084 o Either side (more likely the server-side ETR) decides not to send 1085 a Map-Request. For example, if the server-side ETR does not send 1086 Map-Requests, it gleans RLOCs from the client-side ITR, giving the 1087 client-side ITR responsibility for bidirectional RLOC reachability 1088 and preferability. Server-side ETR gleaning of the client-side 1089 ITR RLOC is done by caching the inner-header source EID and the 1090 outer-header source RLOC of received packets. The client-side ITR 1091 controls how traffic is returned and can alternate using an outer- 1092 header source RLOC, which then can be added to the list the 1093 server-side ETR uses to return traffic. Since no Priority or 1094 Weights are provided using this method, the server-side ETR MUST 1095 assume that each client-side ITR RLOC uses the same best Priority 1096 with a Weight of zero. In addition, since EID-Prefix encoding 1097 cannot be conveyed in data packets, the EID-to-RLOC Cache on 1098 Tunnel Routers can grow to be very large. 1100 Alternatively, RLOC information MAY be gleaned from received tunneled 1101 packets or EID-to-RLOC Map-Request messages. A "gleaned" Map-Cache 1102 entry, one learned from the source RLOC of a received encapsulated 1103 packet, is only stored and used for a few seconds, pending 1104 verification. Verification is performed by sending a Map-Request to 1105 the source EID (the inner-header IP source address) of the received 1106 encapsulated packet. A reply to this "verifying Map-Request" is used 1107 to fully populate the Map-Cache entry for the "gleaned" EID and is 1108 stored and used for the time indicated from the 'TTL' field of a 1109 received Map-Reply. When a verified Map-Cache entry is stored, data 1110 gleaning no longer occurs for subsequent packets that have a source 1111 EID that matches the EID-Prefix of the verified entry. This 1112 "gleaning" mechanism is OPTIONAL, refer to Section 16 for security 1113 issues regarding this mechanism. 1115 RLOCs that appear in EID-to-RLOC Map-Reply messages are assumed to be 1116 reachable when the R-bit [I-D.ietf-lisp-rfc6833bis] for the Locator 1117 record is set to 1. When the R-bit is set to 0, an ITR or PITR MUST 1118 NOT encapsulate to the RLOC. Neither the information contained in a 1119 Map-Reply nor that stored in the mapping database system provides 1120 reachability information for RLOCs. Note that reachability is not 1121 part of the mapping system and is determined using one or more of the 1122 Routing Locator reachability algorithms described in the next 1123 section. 1125 10. Routing Locator Reachability 1127 Several Data-Plane mechanisms for determining RLOC reachability are 1128 currently defined. Please note that additional Control-Plane based 1129 reachability mechanisms are defined in [I-D.ietf-lisp-rfc6833bis]. 1131 1. An ETR MAY examine the Locator-Status-Bits in the LISP header of 1132 an encapsulated data packet received from an ITR. If the ETR is 1133 also acting as an ITR and has traffic to return to the original 1134 ITR site, it can use this status information to help select an 1135 RLOC. 1137 2. When an ETR receives an encapsulated packet from an ITR, the 1138 source RLOC from the outer header of the packet is likely to be 1139 reachable. 1141 3. An ITR/ETR pair can use the 'Echo-Noncing' Locator reachability 1142 algorithms described in this section. 1144 When determining Locator up/down reachability by examining the 1145 Locator-Status-Bits from the LISP-encapsulated data packet, an ETR 1146 will receive up-to-date status from an encapsulating ITR about 1147 reachability for all ETRs at the site. CE-based ITRs at the source 1148 site can determine reachability relative to each other using the site 1149 IGP as follows: 1151 o Under normal circumstances, each ITR will advertise a default 1152 route into the site IGP. 1154 o If an ITR fails or if the upstream link to its PE fails, its 1155 default route will either time out or be withdrawn. 1157 Each ITR can thus observe the presence or lack of a default route 1158 originated by the others to determine the Locator-Status-Bits it sets 1159 for them. 1161 When ITRs at the site are not deployed in CE routers, the IGP can 1162 still be used to determine the reachability of Locators, provided 1163 they are injected into the IGP. This is typically done when a /32 1164 address is configured on a loopback interface. 1166 RLOCs listed in a Map-Reply are numbered with ordinals 0 to n-1. The 1167 Locator-Status-Bits in a LISP-encapsulated packet are numbered from 0 1168 to n-1 starting with the least significant bit. For example, if an 1169 RLOC listed in the 3rd position of the Map-Reply goes down (ordinal 1170 value 2), then all ITRs at the site will clear the 3rd least 1171 significant bit (xxxx x0xx) of the 'Locator-Status-Bits' field for 1172 the packets they encapsulate. 1174 When an ETR decapsulates a packet, it will check for any change in 1175 the 'Locator-Status-Bits' field. When a bit goes from 1 to 0, the 1176 ETR, if acting also as an ITR, will refrain from encapsulating 1177 packets to an RLOC that is indicated as down. It will only resume 1178 using that RLOC if the corresponding Locator-Status-Bit returns to a 1179 value of 1. Locator-Status-Bits are associated with a Locator-Set 1180 per EID-Prefix. Therefore, when a Locator becomes unreachable, the 1181 Locator-Status-Bit that corresponds to that Locator's position in the 1182 list returned by the last Map-Reply will be set to zero for that 1183 particular EID-Prefix. Refer to Section 16 for security related 1184 issues regarding Locator-Status-Bits. 1186 When an ETR decapsulates a packet, it knows that it is reachable from 1187 the encapsulating ITR because that is how the packet arrived. In 1188 most cases, the ETR can also reach the ITR but cannot assume this to 1189 be true, due to the possibility of path asymmetry. In the presence 1190 of unidirectional traffic flow from an ITR to an ETR, the ITR SHOULD 1191 NOT use the lack of return traffic as an indication that the ETR is 1192 unreachable. Instead, it MUST use an alternate mechanism to 1193 determine reachability. 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 next sends a data packet to the 1206 ITR, it includes the nonce received earlier with the N-bit set and 1207 E-bit cleared. The ITR sees this "echoed nonce" and knows that the 1208 path to and from the ETR is up. 1210 The ITR will set the E-bit and N-bit for every packet it sends while 1211 in the echo-nonce-request state. The time the ITR waits to process 1212 the echoed nonce before it determines the path is unreachable is 1213 variable and is a choice left for the implementation. 1215 If the ITR is receiving packets from the ETR but does not see the 1216 nonce echoed while being in the echo-nonce-request state, then the 1217 path to the ETR is unreachable. This decision MAY be overridden by 1218 other Locator reachability algorithms. Once the ITR determines that 1219 the path to the ETR is down, it can switch to another Locator for 1220 that EID-Prefix. 1222 Note that "ITR" and "ETR" are relative terms here. Both devices MUST 1223 be implementing both ITR and ETR functionality for the echo nonce 1224 mechanism to operate. 1226 The ITR and ETR MAY both go into the echo-nonce-request state at the 1227 same time. The number of packets sent or the time during which echo 1228 nonce requests are sent is an implementation-specific setting. 1229 However, when an ITR is in the echo-nonce-request state, it can echo 1230 the ETR's nonce in the next set of packets that it encapsulates and 1231 subsequently continue sending echo-nonce-request packets. 1233 This mechanism does not completely solve the forward path 1234 reachability problem, as traffic may be unidirectional. That is, the 1235 ETR receiving traffic at a site MAY not be the same device as an ITR 1236 that transmits traffic from that site, or the site-to-site traffic is 1237 unidirectional so there is no ITR returning traffic. 1239 The echo-nonce algorithm is bilateral. That is, if one side sets the 1240 E-bit and the other side is not enabled for echo-noncing, then the 1241 echoing of the nonce does not occur and the requesting side may 1242 erroneously consider the Locator unreachable. An ITR SHOULD only set 1243 the E-bit in an encapsulated data packet when it knows the ETR is 1244 enabled for echo-noncing. This is conveyed by the E-bit in the RLOC- 1245 probe Map-Reply message. 1247 11. EID Reachability within a LISP Site 1249 A site MAY be multihomed using two or more ETRs. The hosts and 1250 infrastructure within a site will be addressed using one or more EID- 1251 Prefixes that are mapped to the RLOCs of the relevant ETRs in the 1252 mapping system. One possible failure mode is for an ETR to lose 1253 reachability to one or more of the EID-Prefixes within its own site. 1254 When this occurs when the ETR sends Map-Replies, it can clear the 1255 R-bit associated with its own Locator. And when the ETR is also an 1256 ITR, it can clear its Locator-Status-Bit in the encapsulation data 1257 header. 1259 It is recognized that there are no simple solutions to the site 1260 partitioning problem because it is hard to know which part of the 1261 EID-Prefix range is partitioned and which Locators can reach any sub- 1262 ranges of the EID-Prefixes. Note that this is not a new problem 1263 introduced by the LISP architecture. The problem exists today when a 1264 multihomed site uses BGP to advertise its reachability upstream. 1266 12. Routing Locator Hashing 1268 When an ETR provides an EID-to-RLOC mapping in a Map-Reply message 1269 that is stored in the Map-Cache of a requesting ITR, the Locator-Set 1270 for the EID-Prefix MAY contain different Priority and Weight values 1271 for each locator address. When more than one best Priority Locator 1272 exists, the ITR can decide how to load-share traffic against the 1273 corresponding Locators. 1275 The following hash algorithm MAY be used by an ITR to select a 1276 Locator for a packet destined to an EID for the EID-to-RLOC mapping: 1278 1. Either a source and destination address hash or the traditional 1279 5-tuple hash can be used. The traditional 5-tuple hash includes 1280 the source and destination addresses; source and destination TCP, 1281 UDP, or Stream Control Transmission Protocol (SCTP) port numbers; 1282 and the IP protocol number field or IPv6 next-protocol fields of 1283 a packet that a host originates from within a LISP site. When a 1284 packet is not a TCP, UDP, or SCTP packet, the source and 1285 destination addresses only from the header are used to compute 1286 the hash. 1288 2. Take the hash value and divide it by the number of Locators 1289 stored in the Locator-Set for the EID-to-RLOC mapping. 1291 3. The remainder will yield a value of 0 to "number of Locators 1292 minus 1". Use the remainder to select the Locator in the 1293 Locator-Set. 1295 Note that when a packet is LISP encapsulated, the source port number 1296 in the outer UDP header needs to be set. Selecting a hashed value 1297 allows core routers that are attached to Link Aggregation Groups 1298 (LAGs) to load-split the encapsulated packets across member links of 1299 such LAGs. Otherwise, core routers would see a single flow, since 1300 packets have a source address of the ITR, for packets that are 1301 originated by different EIDs at the source site. A suggested setting 1302 for the source port number computed by an ITR is a 5-tuple hash 1303 function on the inner header, as described above. The source port 1304 SHOULD be the same for all packets belonging to the same flow. 1306 Many core router implementations use a 5-tuple hash to decide how to 1307 balance packet load across members of a LAG. The 5-tuple hash 1308 includes the source and destination addresses of the packet and the 1309 source and destination ports when the protocol number in the packet 1310 is TCP or UDP. For this reason, UDP encoding is used for LISP 1311 encapsulation. 1313 13. Changing the Contents of EID-to-RLOC Mappings 1315 Since the LISP architecture uses a caching scheme to retrieve and 1316 store EID-to-RLOC mappings, the only way an ITR can get a more up-to- 1317 date mapping is to re-request the mapping. However, the ITRs do not 1318 know when the mappings change, and the ETRs do not keep track of 1319 which ITRs requested its mappings. For scalability reasons, it is 1320 desirable to maintain this approach but need to provide a way for 1321 ETRs to change their mappings and inform the sites that are currently 1322 communicating with the ETR site using such mappings. 1324 This section defines a Data-Plane mechanism for updating EID-to-RLOC 1325 mappings. Additionally, the Solicit-Map Request (SMR) Control-Plane 1326 updating mechanism is specified in [I-D.ietf-lisp-rfc6833bis]. 1328 When adding a new Locator record in lexicographic order to the end of 1329 a Locator-Set, it is easy to update mappings. We assume that new 1330 mappings will maintain the same Locator ordering as the old mapping 1331 but will just have new Locators appended to the end of the list. So, 1332 some ITRs can have a new mapping while other ITRs have only an old 1333 mapping that is used until they time out. When an ITR has only an 1334 old mapping but detects bits set in the Locator-Status-Bits that 1335 correspond to Locators beyond the list it has cached, it simply 1336 ignores them. However, this can only happen for locator addresses 1337 that are lexicographically greater than the locator addresses in the 1338 existing Locator-Set. 1340 When a Locator record is inserted in the middle of a Locator-Set, to 1341 maintain lexicographic order, SMR procedure 1342 [I-D.ietf-lisp-rfc6833bis] is used to inform ITRs and PITRs of the 1343 new Locator-Status-Bit mappings. 1345 When a Locator record is removed from a Locator-Set, ITRs that have 1346 the mapping cached will not use the removed Locator because the xTRs 1347 will set the Locator-Status-Bit to 0. So, even if the Locator is in 1348 the list, it will not be used. For new mapping requests, the xTRs 1349 can set the Locator AFI to 0 (indicating an unspecified address), as 1350 well as setting the corresponding Locator-Status-Bit to 0. This 1351 forces ITRs with old or new mappings to avoid using the removed 1352 Locator. 1354 If many changes occur to a mapping over a long period of time, one 1355 will find empty record slots in the middle of the Locator-Set and new 1356 records appended to the Locator-Set. At some point, it would be 1357 useful to compact the Locator-Set so the Locator-Status-Bit settings 1358 can be efficiently packed. 1360 We propose here a Data-Plane mechanism (Map-Versioning specified in 1361 [I-D.ietf-lisp-6834bis]) to update the contents of EID-to-RLOC 1362 mappings. Please note that in addition the Solicit-Map Request 1363 (specified in [I-D.ietf-lisp-rfc6833bis]) is a Control-Plane 1364 mechanisms that can be used to update EID-to-RLOC mappings. 1366 13.1. Database Map-Versioning 1368 When there is unidirectional packet flow between an ITR and ETR, and 1369 the EID-to-RLOC mappings change on the ETR, it needs to inform the 1370 ITR so encapsulation to a removed Locator can stop and can instead be 1371 started to a new Locator in the Locator-Set. 1373 An ETR, when it sends Map-Reply messages, conveys its own Map-Version 1374 Number. This is known as the Destination Map-Version Number. ITRs 1375 include the Destination Map-Version Number in packets they 1376 encapsulate to the site. When an ETR decapsulates a packet and 1377 detects that the Destination Map-Version Number is less than the 1378 current version for its mapping, the SMR procedure described in 1379 [I-D.ietf-lisp-rfc6833bis] occurs. 1381 An ITR, when it encapsulates packets to ETRs, can convey its own Map- 1382 Version Number. This is known as the Source Map-Version Number. 1383 When an ETR decapsulates a packet and detects that the Source Map- 1384 Version Number is greater than the last Map-Version Number sent in a 1385 Map-Reply from the ITR's site, the ETR will send a Map-Request to one 1386 of the ETRs for the source site. 1388 A Map-Version Number is used as a sequence number per EID-Prefix, so 1389 values that are greater are considered to be more recent. A value of 1390 0 for the Source Map-Version Number or the Destination Map-Version 1391 Number conveys no versioning information, and an ITR does no 1392 comparison with previously received Map-Version Numbers. 1394 A Map-Version Number can be included in Map-Register messages as 1395 well. This is a good way for the Map-Server to assure that all ETRs 1396 for a site registering to it will be synchronized according to Map- 1397 Version Number. 1399 See [I-D.ietf-lisp-6834bis] for a more detailed analysis and 1400 description of Database Map-Versioning. 1402 14. Multicast Considerations 1404 A multicast group address, as defined in the original Internet 1405 architecture, is an identifier of a grouping of topologically 1406 independent receiver host locations. The address encoding itself 1407 does not determine the location of the receiver(s). The multicast 1408 routing protocol, and the network-based state the protocol creates, 1409 determine where the receivers are located. 1411 In the context of LISP, a multicast group address is both an EID and 1412 a Routing Locator. Therefore, no specific semantic or action needs 1413 to be taken for a destination address, as it would appear in an IP 1414 header. Therefore, a group address that appears in an inner IP 1415 header built by a source host will be used as the destination EID. 1416 The outer IP header (the destination Routing Locator address), 1417 prepended by a LISP router, can use the same group address as the 1418 destination Routing Locator, use a multicast or unicast Routing 1419 Locator obtained from a Mapping System lookup, or use other means to 1420 determine the group address mapping. 1422 With respect to the source Routing Locator address, the ITR prepends 1423 its own IP address as the source address of the outer IP header. 1424 Just like it would if the destination EID was a unicast address. 1425 This source Routing Locator address, like any other Routing Locator 1426 address, MUST be globally routable. 1428 There are two approaches for LISP-Multicast, one that uses native 1429 multicast routing in the underlay with no support from the Mapping 1430 System and the other that uses only unicast routing in the underlay 1431 with support from the Mapping System. See [RFC6831] and [RFC8378], 1432 respectively, for details. Details for LISP-Multicast and 1433 interworking with non-LISP sites are described in [RFC6831] and 1434 [RFC6832]. 1436 15. Router Performance Considerations 1438 LISP is designed to be very "hardware-based forwarding friendly". A 1439 few implementation techniques can be used to incrementally implement 1440 LISP: 1442 o When a tunnel-encapsulated packet is received by an ETR, the outer 1443 destination address may not be the address of the router. This 1444 makes it challenging for the control plane to get packets from the 1445 hardware. This may be mitigated by creating special Forwarding 1446 Information Base (FIB) entries for the EID-Prefixes of EIDs served 1447 by the ETR (those for which the router provides an RLOC 1448 translation). These FIB entries are marked with a flag indicating 1449 that Control-Plane processing SHOULD be performed. The forwarding 1450 logic of testing for particular IP protocol number values is not 1451 necessary. There are a few proven cases where no changes to 1452 existing deployed hardware were needed to support the LISP Data- 1453 Plane. 1455 o On an ITR, prepending a new IP header consists of adding more 1456 octets to a MAC rewrite string and prepending the string as part 1457 of the outgoing encapsulation procedure. Routers that support 1458 Generic Routing Encapsulation (GRE) tunneling [RFC2784] or 6to4 1459 tunneling [RFC3056] may already support this action. 1461 o A packet's source address or interface the packet was received on 1462 can be used to select VRF (Virtual Routing/Forwarding). The VRF's 1463 routing table can be used to find EID-to-RLOC mappings. 1465 For performance issues related to Map-Cache management, see 1466 Section 16. 1468 16. Security Considerations 1470 A complete LISP threat analysis can be found in [RFC7835] in what 1471 follows we provide a summary when LISP is deployed in non-trustable 1472 environments. 1474 The optional mechanisms of gleaning is offered to directly obtain a 1475 mapping from the LISP encapsulated packets. Specifically, an xTR can 1476 learn the EID-to-RLOC mapping by inspecting the source RLOC and 1477 source EID of an encapsulated packet, and insert this new mapping 1478 into its Map-Cache. An off-path attacker can spoof the source EID 1479 address to divert the traffic sent to the victim's spoofed EID. If 1480 the attacker spoofs the source RLOC, it can mount a DoS attack by 1481 redirecting traffic to the spoofed victim's RLOC, potentially 1482 overloading it. 1484 The LISP Data-Plane defines several mechanisms to monitor RLOC Data- 1485 Plane reachability, in this context Locator-Status Bits, Nonce- 1486 Present and Echo-Nonce bits of the LISP encapsulation header can be 1487 manipulated by an attacker to mount a DoS attack. An off-path 1488 attacker able to spoof the RLOC of a victim's xTR can manipulate such 1489 mechanisms to declare a set of RLOCs unreachable. This can be used 1490 also, for instance, to declare only one RLOC reachable with the aim 1491 of overload it. 1493 Map-Versioning is a Data-Plane mechanism used to signal a peering xTR 1494 that a local EID-to-RLOC mapping has been updated, so that the 1495 peering xTR uses LISP Control-Plane signaling message to retrieve a 1496 fresh mapping. This can be used by an attacker to forge the map- 1497 versioning field of a LISP encapsulated header and force an excessive 1498 amount of signaling between xTRs that may overload them. 1500 Most of the attack vectors can be mitigated with careful deployment 1501 and configuration, information learned opportunistically (such as LSB 1502 or gleaning) SHOULD be verified with other reachability mechanisms. 1503 In addition, systematic rate-limitation and filtering is an effective 1504 technique to mitigate attacks that aim to overload the Control-Plane. 1506 17. Network Management Considerations 1508 Considerations for network management tools exist so the LISP 1509 protocol suite can be operationally managed. These mechanisms can be 1510 found in [RFC7052] and [RFC6835]. 1512 18. Changes since RFC 6830 1514 For implementation considerations, the following changes have been 1515 made to this document since RFC 6830 was published: 1517 o It is no longer mandated that a maximum number of 2 LISP headers 1518 be prepended to a packet. If there is a application need for more 1519 than 2 LISP headers, an implementation can support more. However, 1520 it is RECOMMENDED that a maximum of two LISP headers can be 1521 prepended to a packet. 1523 o The 3 reserved flag bits in the LISP header have been allocated 1524 for [RFC8061]. The low-order 2 bits of the 3-bit field (now named 1525 the KK bits) are used as a key identifier. The 1 remaining bit is 1526 still documented as reserved. 1528 o Data-Plane gleaning for creating map-cache entries has been made 1529 optional. Any ITR implementations that depend on or assume the 1530 remote ETR is gleaning should not do so. This does not create any 1531 interoperability problems since the control-plane map-cache 1532 population procedures are unilateral and are the typical method 1533 for map-cache population. 1535 o The bulk of the changes to this document which reduces its length 1536 are due to moving the LISP control-plane messaging and procedures 1537 to [I-D.ietf-lisp-rfc6833bis]. 1539 19. IANA Considerations 1541 This section provides guidance to the Internet Assigned Numbers 1542 Authority (IANA) regarding registration of values related to this 1543 Data-Plane LISP specification, in accordance with BCP 26 [RFC8126]. 1545 19.1. LISP UDP Port Numbers 1547 The IANA registry has allocated UDP port number 4341 for the LISP 1548 Data-Plane. IANA has updated the description for UDP port 4341 as 1549 follows: 1551 lisp-data 4341 udp LISP Data Packets 1553 20. References 1555 20.1. Normative References 1557 [I-D.ietf-lisp-6834bis] 1558 Iannone, L., Saucez, D., and O. Bonaventure, "Locator/ID 1559 Separation Protocol (LISP) Map-Versioning", draft-ietf- 1560 lisp-6834bis-02 (work in progress), September 2018. 1562 [I-D.ietf-lisp-rfc6833bis] 1563 Fuller, V., Farinacci, D., and A. Cabellos-Aparicio, 1564 "Locator/ID Separation Protocol (LISP) Control-Plane", 1565 draft-ietf-lisp-rfc6833bis-16 (work in progress), 1566 September 2018. 1568 [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, 1569 DOI 10.17487/RFC0768, August 1980, 1570 . 1572 [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, 1573 DOI 10.17487/RFC0791, September 1981, 1574 . 1576 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1577 Requirement Levels", BCP 14, RFC 2119, 1578 DOI 10.17487/RFC2119, March 1997, 1579 . 1581 [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, 1582 "Definition of the Differentiated Services Field (DS 1583 Field) in the IPv4 and IPv6 Headers", RFC 2474, 1584 DOI 10.17487/RFC2474, December 1998, 1585 . 1587 [RFC6040] Briscoe, B., "Tunnelling of Explicit Congestion 1588 Notification", RFC 6040, DOI 10.17487/RFC6040, November 1589 2010, . 1591 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1592 Writing an IANA Considerations Section in RFCs", BCP 26, 1593 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1594 . 1596 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1597 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1598 May 2017, . 1600 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1601 (IPv6) Specification", STD 86, RFC 8200, 1602 DOI 10.17487/RFC8200, July 2017, 1603 . 1605 20.2. Informative References 1607 [AFN] IANA, "Address Family Numbers", August 2016, 1608 . 1610 [CHIAPPA] Chiappa, J., "Endpoints and Endpoint names: A Proposed", 1611 1999, 1612 . 1614 [I-D.ietf-lisp-introduction] 1615 Cabellos-Aparicio, A. and D. Saucez, "An Architectural 1616 Introduction to the Locator/ID Separation Protocol 1617 (LISP)", draft-ietf-lisp-introduction-13 (work in 1618 progress), April 2015. 1620 [I-D.ietf-lisp-vpn] 1621 Moreno, V. and D. Farinacci, "LISP Virtual Private 1622 Networks (VPNs)", draft-ietf-lisp-vpn-02 (work in 1623 progress), May 2018. 1625 [OPENLISP] 1626 Iannone, L., Saucez, D., and O. Bonaventure, "OpenLISP 1627 Implementation Report", Work in Progress, July 2008. 1629 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 1630 STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, 1631 . 1633 [RFC1918] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G., 1634 and E. Lear, "Address Allocation for Private Internets", 1635 BCP 5, RFC 1918, DOI 10.17487/RFC1918, February 1996, 1636 . 1638 [RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. 1639 Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, 1640 DOI 10.17487/RFC2784, March 2000, 1641 . 1643 [RFC3056] Carpenter, B. and K. Moore, "Connection of IPv6 Domains 1644 via IPv4 Clouds", RFC 3056, DOI 10.17487/RFC3056, February 1645 2001, . 1647 [RFC3232] Reynolds, J., Ed., "Assigned Numbers: RFC 1700 is Replaced 1648 by an On-line Database", RFC 3232, DOI 10.17487/RFC3232, 1649 January 2002, . 1651 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, 1652 A., Peterson, J., Sparks, R., Handley, M., and E. 1653 Schooler, "SIP: Session Initiation Protocol", RFC 3261, 1654 DOI 10.17487/RFC3261, June 2002, 1655 . 1657 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 1658 "Randomness Requirements for Security", BCP 106, RFC 4086, 1659 DOI 10.17487/RFC4086, June 2005, 1660 . 1662 [RFC4984] Meyer, D., Ed., Zhang, L., Ed., and K. Fall, Ed., "Report 1663 from the IAB Workshop on Routing and Addressing", 1664 RFC 4984, DOI 10.17487/RFC4984, September 2007, 1665 . 1667 [RFC6831] Farinacci, D., Meyer, D., Zwiebel, J., and S. Venaas, "The 1668 Locator/ID Separation Protocol (LISP) for Multicast 1669 Environments", RFC 6831, DOI 10.17487/RFC6831, January 1670 2013, . 1672 [RFC6832] Lewis, D., Meyer, D., Farinacci, D., and V. Fuller, 1673 "Interworking between Locator/ID Separation Protocol 1674 (LISP) and Non-LISP Sites", RFC 6832, 1675 DOI 10.17487/RFC6832, January 2013, 1676 . 1678 [RFC6835] Farinacci, D. and D. Meyer, "The Locator/ID Separation 1679 Protocol Internet Groper (LIG)", RFC 6835, 1680 DOI 10.17487/RFC6835, January 2013, 1681 . 1683 [RFC6935] Eubanks, M., Chimento, P., and M. Westerlund, "IPv6 and 1684 UDP Checksums for Tunneled Packets", RFC 6935, 1685 DOI 10.17487/RFC6935, April 2013, 1686 . 1688 [RFC6936] Fairhurst, G. and M. Westerlund, "Applicability Statement 1689 for the Use of IPv6 UDP Datagrams with Zero Checksums", 1690 RFC 6936, DOI 10.17487/RFC6936, April 2013, 1691 . 1693 [RFC7052] Schudel, G., Jain, A., and V. Moreno, "Locator/ID 1694 Separation Protocol (LISP) MIB", RFC 7052, 1695 DOI 10.17487/RFC7052, October 2013, 1696 . 1698 [RFC7215] Jakab, L., Cabellos-Aparicio, A., Coras, F., Domingo- 1699 Pascual, J., and D. Lewis, "Locator/Identifier Separation 1700 Protocol (LISP) Network Element Deployment 1701 Considerations", RFC 7215, DOI 10.17487/RFC7215, April 1702 2014, . 1704 [RFC7833] Howlett, J., Hartman, S., and A. Perez-Mendez, Ed., "A 1705 RADIUS Attribute, Binding, Profiles, Name Identifier 1706 Format, and Confirmation Methods for the Security 1707 Assertion Markup Language (SAML)", RFC 7833, 1708 DOI 10.17487/RFC7833, May 2016, 1709 . 1711 [RFC7835] Saucez, D., Iannone, L., and O. Bonaventure, "Locator/ID 1712 Separation Protocol (LISP) Threat Analysis", RFC 7835, 1713 DOI 10.17487/RFC7835, April 2016, 1714 . 1716 [RFC8060] Farinacci, D., Meyer, D., and J. Snijders, "LISP Canonical 1717 Address Format (LCAF)", RFC 8060, DOI 10.17487/RFC8060, 1718 February 2017, . 1720 [RFC8061] Farinacci, D. and B. Weis, "Locator/ID Separation Protocol 1721 (LISP) Data-Plane Confidentiality", RFC 8061, 1722 DOI 10.17487/RFC8061, February 2017, 1723 . 1725 [RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage 1726 Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085, 1727 March 2017, . 1729 [RFC8111] Fuller, V., Lewis, D., Ermagan, V., Jain, A., and A. 1730 Smirnov, "Locator/ID Separation Protocol Delegated 1731 Database Tree (LISP-DDT)", RFC 8111, DOI 10.17487/RFC8111, 1732 May 2017, . 1734 [RFC8378] Moreno, V. and D. Farinacci, "Signal-Free Locator/ID 1735 Separation Protocol (LISP) Multicast", RFC 8378, 1736 DOI 10.17487/RFC8378, May 2018, 1737 . 1739 Appendix A. Acknowledgments 1741 An initial thank you goes to Dave Oran for planting the seeds for the 1742 initial ideas for LISP. His consultation continues to provide value 1743 to the LISP authors. 1745 A special and appreciative thank you goes to Noel Chiappa for 1746 providing architectural impetus over the past decades on separation 1747 of location and identity, as well as detailed reviews of the LISP 1748 architecture and documents, coupled with enthusiasm for making LISP a 1749 practical and incremental transition for the Internet. 1751 The authors would like to gratefully acknowledge many people who have 1752 contributed discussions and ideas to the making of this proposal. 1753 They include Scott Brim, Andrew Partan, John Zwiebel, Jason Schiller, 1754 Lixia Zhang, Dorian Kim, Peter Schoenmaker, Vijay Gill, Geoff Huston, 1755 David Conrad, Mark Handley, Ron Bonica, Ted Seely, Mark Townsley, 1756 Chris Morrow, Brian Weis, Dave McGrew, Peter Lothberg, Dave Thaler, 1757 Eliot Lear, Shane Amante, Ved Kafle, Olivier Bonaventure, Luigi 1758 Iannone, Robin Whittle, Brian Carpenter, Joel Halpern, Terry 1759 Manderson, Roger Jorgensen, Ran Atkinson, Stig Venaas, Iljitsch van 1760 Beijnum, Roland Bless, Dana Blair, Bill Lynch, Marc Woolward, Damien 1761 Saucez, Damian Lezama, Attilla De Groot, Parantap Lahiri, David 1762 Black, Roque Gagliano, Isidor Kouvelas, Jesper Skriver, Fred Templin, 1763 Margaret Wasserman, Sam Hartman, Michael Hofling, Pedro Marques, Jari 1764 Arkko, Gregg Schudel, Srinivas Subramanian, Amit Jain, Xu Xiaohu, 1765 Dhirendra Trivedi, Yakov Rekhter, John Scudder, John Drake, Dimitri 1766 Papadimitriou, Ross Callon, Selina Heimlich, Job Snijders, Vina 1767 Ermagan, Fabio Maino, Victor Moreno, Chris White, Clarence Filsfils, 1768 Alia Atlas, Florin Coras and Alberto Rodriguez. 1770 This work originated in the Routing Research Group (RRG) of the IRTF. 1771 An individual submission was converted into the IETF LISP working 1772 group document that became this RFC. 1774 The LISP working group would like to give a special thanks to Jari 1775 Arkko, the Internet Area AD at the time that the set of LISP 1776 documents were being prepared for IESG last call, and for his 1777 meticulous reviews and detailed commentaries on the 7 working group 1778 last call documents progressing toward standards-track RFCs. 1780 Appendix B. Document Change Log 1782 [RFC Editor: Please delete this section on publication as RFC.] 1784 B.1. Changes to draft-ietf-lisp-rfc6830bis-21 1786 o Late-September 2018. 1788 o Changes to reflect comments from Sep 27th Telechat. 1790 B.2. Changes to draft-ietf-lisp-rfc6830bis-20 1792 o Posted late-September 2018. 1794 o Fix old reference to RFC3168, changed to RFC6040. 1796 B.3. Changes to draft-ietf-lisp-rfc6830bis-19 1798 o Posted late-September 2018. 1800 o More editorial changes. 1802 B.4. Changes to draft-ietf-lisp-rfc6830bis-18 1804 o Posted mid-September 2018. 1806 o Changes to reflect comments from Secdir review (Mirja). 1808 B.5. Changes to draft-ietf-lisp-rfc6830bis-17 1810 o Posted September 2018. 1812 o Indicate in the "Changes since RFC 6830" section why the document 1813 has been shortened in length. 1815 o Make reference to RFC 8085 about UDP congestion control. 1817 o More editorial changes from multiple IESG reviews. 1819 B.6. Changes to draft-ietf-lisp-rfc6830bis-16 1821 o Posted late August 2018. 1823 o Distinguish the message type names between ICMP for IPv4 and ICMP 1824 for IPv6 for handling MTU issues. 1826 B.7. Changes to draft-ietf-lisp-rfc6830bis-15 1828 o Posted August 2018. 1830 o Final editorial changes before RFC submission for Proposed 1831 Standard. 1833 o Added section "Changes since RFC 6830" so implementers are 1834 informed of any changes since the last RFC publication. 1836 B.8. Changes to draft-ietf-lisp-rfc6830bis-14 1838 o Posted July 2018 IETF week. 1840 o Put obsolete of RFC 6830 in Intro section in addition to abstract. 1842 B.9. Changes to draft-ietf-lisp-rfc6830bis-13 1844 o Posted March IETF Week 2018. 1846 o Clarified that a new nonce is required per RLOC. 1848 o Removed 'Clock Sweep' section. This text must be placed in a new 1849 OAM document. 1851 o Some references changed from normative to informative 1853 B.10. Changes to draft-ietf-lisp-rfc6830bis-12 1855 o Posted July 2018. 1857 o Fixed Luigi editorial comments to ready draft for RFC status. 1859 B.11. Changes to draft-ietf-lisp-rfc6830bis-11 1861 o Posted March 2018. 1863 o Removed sections 16, 17 and 18 (Mobility, Deployment and 1864 Traceroute considerations). This text must be placed in a new OAM 1865 document. 1867 B.12. Changes to draft-ietf-lisp-rfc6830bis-10 1869 o Posted March 2018. 1871 o Updated section 'Router Locator Selection' stating that the Data- 1872 Plane MUST follow what's stored in the Map-Cache (priorities and 1873 weights). 1875 o Section 'Routing Locator Reachability': Removed bullet point 2 1876 (ICMP Network/Host Unreachable),3 (hints from BGP),4 (ICMP Port 1877 Unreachable),5 (receive a Map-Reply as a response) and RLOC 1878 probing 1880 o Removed 'Solicit-Map Request'. 1882 B.13. Changes to draft-ietf-lisp-rfc6830bis-09 1884 o Posted January 2018. 1886 o Add more details in section 5.3 about DSCP processing during 1887 encapsulation and decapsulation. 1889 o Added clarity to definitions in the Definition of Terms section 1890 from various commenters. 1892 o Removed PA and PI definitions from Definition of Terms section. 1894 o More editorial changes. 1896 o Removed 4342 from IANA section and move to RFC6833 IANA section. 1898 B.14. Changes to draft-ietf-lisp-rfc6830bis-08 1900 o Posted January 2018. 1902 o Remove references to research work for any protocol mechanisms. 1904 o Document scanned to make sure it is RFC 2119 compliant. 1906 o Made changes to reflect comments from document WG shepherd Luigi 1907 Iannone. 1909 o Ran IDNITs on the document. 1911 B.15. Changes to draft-ietf-lisp-rfc6830bis-07 1913 o Posted November 2017. 1915 o Rephrase how Instance-IDs are used and don't refer to [RFC1918] 1916 addresses. 1918 B.16. Changes to draft-ietf-lisp-rfc6830bis-06 1920 o Posted October 2017. 1922 o Put RTR definition before it is used. 1924 o Rename references that are now working group drafts. 1926 o Remove "EIDs MUST NOT be used as used by a host to refer to other 1927 hosts. Note that EID blocks MAY LISP RLOCs". 1929 o Indicate what address-family can appear in data packets. 1931 o ETRs may, rather than will, be the ones to send Map-Replies. 1933 o Recommend, rather than mandate, max encapsulation headers to 2. 1935 o Reference VPN draft when introducing Instance-ID. 1937 o Indicate that SMRs can be sent when ITR/ETR are in the same node. 1939 o Clarify when private addresses can be used. 1941 B.17. Changes to draft-ietf-lisp-rfc6830bis-05 1943 o Posted August 2017. 1945 o Make it clear that a Re-encapsulating Tunnel Router is an RTR. 1947 B.18. Changes to draft-ietf-lisp-rfc6830bis-04 1949 o Posted July 2017. 1951 o Changed reference of IPv6 RFC2460 to RFC8200. 1953 o Indicate that the applicability statement for UDP zero checksums 1954 over IPv6 adheres to RFC6936. 1956 B.19. Changes to draft-ietf-lisp-rfc6830bis-03 1958 o Posted May 2017. 1960 o Move the control-plane related codepoints in the IANA 1961 Considerations section to RFC6833bis. 1963 B.20. Changes to draft-ietf-lisp-rfc6830bis-02 1965 o Posted April 2017. 1967 o Reflect some editorial comments from Damien Sausez. 1969 B.21. Changes to draft-ietf-lisp-rfc6830bis-01 1971 o Posted March 2017. 1973 o Include references to new RFCs published. 1975 o Change references from RFC6833 to RFC6833bis. 1977 o Clarified LCAF text in the IANA section. 1979 o Remove references to "experimental". 1981 B.22. Changes to draft-ietf-lisp-rfc6830bis-00 1983 o Posted December 2016. 1985 o Created working group document from draft-farinacci-lisp 1986 -rfc6830-00 individual submission. No other changes made. 1988 Authors' Addresses 1990 Dino Farinacci 1991 Cisco Systems 1992 Tasman Drive 1993 San Jose, CA 95134 1994 USA 1996 EMail: farinacci@gmail.com 1998 Vince Fuller 1999 Cisco Systems 2000 Tasman Drive 2001 San Jose, CA 95134 2002 USA 2004 EMail: vince.fuller@gmail.com 2006 Dave Meyer 2007 Cisco Systems 2008 170 Tasman Drive 2009 San Jose, CA 2010 USA 2012 EMail: dmm@1-4-5.net 2014 Darrel Lewis 2015 Cisco Systems 2016 170 Tasman Drive 2017 San Jose, CA 2018 USA 2020 EMail: darlewis@cisco.com 2021 Albert Cabellos 2022 UPC/BarcelonaTech 2023 Campus Nord, C. Jordi Girona 1-3 2024 Barcelona, Catalunya 2025 Spain 2027 EMail: acabello@ac.upc.edu