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Checking references for intended status: Experimental ---------------------------------------------------------------------------- == Missing Reference: 'RFC5925' is mentioned on line 772, but not defined == Missing Reference: 'RFC4895' is mentioned on line 773, but not defined == Unused Reference: 'I-D.ietf-lisp-lcaf' is defined on line 810, but no explicit reference was found in the text == Unused Reference: 'RFC6830' is defined on line 831, but no explicit reference was found in the text == Outdated reference: A later version (-22) exists of draft-ietf-lisp-lcaf-14 ** Obsolete normative reference: RFC 6830 (Obsoleted by RFC 9300, RFC 9301) ** Obsolete normative reference: RFC 6833 (Obsoleted by RFC 9301) Summary: 3 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 C. Cassar 3 Internet-Draft Cisco Systems 4 Intended status: Experimental I. Kouvelas 5 Expires: February 19, 2017 Arista Networks Inc. 6 D. Lewis 7 J. Arango 8 J. Leong 9 Cisco Systems 10 August 18, 2016 12 LISP Map Server Reliable Transport 13 draft-kouvelas-lisp-map-server-reliable-transport-02.txt 15 Abstract 17 The communication between LISP ETRs and Map-Servers is based on 18 unreliable UDP message exchange coupled with periodic message 19 transmission in order to maintain soft state. The drawback of 20 periodic messaging is the constant load imposed on both the ETR and 21 the Map-Server. New use cases for LISP have increased the amount of 22 state that needs to be communicated with requirements that are not 23 satisfied by the current mechanism. This document introduces the use 24 of a reliable transport for ETR to Map-Server communication in order 25 to eliminate the periodic messaging overhead, while providing 26 reliability, flow-control and endpoint liveness detection. 28 This document has been renamed to avoid ambiguity. It is an update 29 to [I-D.kouvelas-lisp-reliable-transport]. 31 Status of This Memo 33 This Internet-Draft is submitted in full conformance with the 34 provisions of BCP 78 and BCP 79. 36 Internet-Drafts are working documents of the Internet Engineering 37 Task Force (IETF). Note that other groups may also distribute 38 working documents as Internet-Drafts. The list of current Internet- 39 Drafts is at http://datatracker.ietf.org/drafts/current/. 41 Internet-Drafts are draft documents valid for a maximum of six months 42 and may be updated, replaced, or obsoleted by other documents at any 43 time. It is inappropriate to use Internet-Drafts as reference 44 material or to cite them other than as "work in progress." 46 This Internet-Draft will expire on February 19, 2017. 48 Copyright Notice 50 Copyright (c) 2016 IETF Trust and the persons identified as the 51 document authors. All rights reserved. 53 This document is subject to BCP 78 and the IETF Trust's Legal 54 Provisions Relating to IETF Documents 55 (http://trustee.ietf.org/license-info) in effect on the date of 56 publication of this document. Please review these documents 57 carefully, as they describe your rights and restrictions with respect 58 to this document. Code Components extracted from this document must 59 include Simplified BSD License text as described in Section 4.e of 60 the Trust Legal Provisions and are provided without warranty as 61 described in the Simplified BSD License. 63 Table of Contents 65 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 66 2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 3 67 3. Message Format . . . . . . . . . . . . . . . . . . . . . . . 4 68 4. Session Establishment . . . . . . . . . . . . . . . . . . . . 5 69 5. Error Notifications . . . . . . . . . . . . . . . . . . . . . 5 70 6. EID Prefix Registration . . . . . . . . . . . . . . . . . . . 7 71 6.1. Reliable Mapping Registration Messages . . . . . . . . . 7 72 6.1.1. Registration Message . . . . . . . . . . . . . . . . 8 73 6.1.2. Registration Acknowledgement Message . . . . . . . . 8 74 6.1.3. Registration Rejection Message . . . . . . . . . . . 9 75 6.1.4. Registration Refresh Message . . . . . . . . . . . . 10 76 6.1.5. Mapping Notification Message . . . . . . . . . . . . 12 77 6.2. ETR Behavior . . . . . . . . . . . . . . . . . . . . . . 13 78 6.3. Map-Server Behavior . . . . . . . . . . . . . . . . . . . 17 79 7. Security Considerations . . . . . . . . . . . . . . . . . . . 18 80 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 81 8.1. LISP Reliable Transport Message Types . . . . . . . . . . 18 82 8.2. Transport Protocol Port Numbers . . . . . . . . . . . . . 18 83 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 84 10. Normative References . . . . . . . . . . . . . . . . . . . . 19 85 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19 87 1. Introduction 89 The communication channel between LISP ETRs and Map-Servers is based 90 on unreliable UDP message exchange [RFC6833]. Where required, 91 reliability is pursued through periodic retransmissions that maintain 92 soft state on the peer. Map-Register messages are retransmitted 93 every minute by an ETR and the Map-Server times out its state if the 94 state is not refreshed for three successive periods. When 95 registering multiple EID-Prefixes, the ETR includes multiple mapping 96 records in the Map-Register message. Packet size limitations provide 97 an upper bound to the number of mapping records that can be placed in 98 each Map-Register message. When the ETR has more EID-Prefixes to 99 register than can be packed in a single Map-Register message, the 100 mapping records for the EID-Prefixes are split across multiple Map- 101 Register messages. 103 The drawback of the periodic registration is the constant load that 104 it introduces on both the ETR and the Map-Server. The ETR uses 105 resources to periodically build and transmit the Map-Register 106 messages, and to process the resulting Map-Notify messages issued by 107 the Map-Server. The Map-Server uses resources to process the 108 received Map-Register messages, update the corresponding registration 109 state, and build and transmit the matching Map-Notify messages. When 110 the number of EID-Prefixes to be registered by an ETR is small, the 111 resulting load imposed by periodic registrations may not be 112 significant. The ETR will only transmit a single Map-Register 113 message each period that contains a small number of mapping records. 115 In some LISP deployments, a large set of EID-Prefixes must be 116 registered by each ETR (e.g. mobility, database redistribution). Use 117 cases with a large set of EID-Prefixes behind an ETR will result in a 118 much higher load. An example is LISP mobility deployments where EID- 119 Prefixes are limited to host entries. ETRs may have thousands of 120 hosts to register resulting in hundreds of Map-Register and Map- 121 Notify messages per registration period. 123 A transport is required for the ETR to Map-Server communication that 124 provides reliability, flow-control and endpoint liveness 125 notifications. This document describes the use of TCP or SCTP as a 126 LISP reliable transport. The initial application for the LISP 127 reliable transport session is the support of scalable EID prefix 128 registration. The reliable session mechanism is defined to be 129 extensible so that it can support additional LISP communication 130 requirements as they arise using a single reliable transport session 131 between an ETR and a Map-Server. The use of the reliable transport 132 session for EID prefix registration is an alternative and does not 133 replace the existing UDP based mechanism. 135 2. Requirements Notation 137 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 138 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 139 document are to be interpreted as described in [RFC2119]. 141 3. Message Format 143 A single LISP reliable transport session may carry information for 144 multiple LISP applications. One such application is the registration 145 of EID to RLOC mappings that operates over a session between an ETR 146 and a Map-Server. Communication over a session is based on the 147 exchange of messages. This document defines a base set of messages 148 to support session establishment and management. It also defines the 149 messages for the EID to RLOC mapping registration application. 151 To support protocol extensibility when new applications, or 152 extensions to existing applications are introduced, the messages are 153 based on a TLV format. 155 0 1 2 3 156 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 1 157 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 158 | Type | Length | 159 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 160 | Message ID | 161 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 162 | Message Data ... 163 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 164 | Message End Marker | 165 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 167 Reliable transport message format 169 o Type: 16 bit type field identifying the message type. 171 o Length: 16 bit field that provides the total size of the message 172 in octets including the length, type and end marker fields. The 173 length allows the receiver to locate the next message in the TCP 174 stream. The minimum value of the length field is 8. 176 o ID: A 32-bit value that identifies the message. May be used by 177 the receiver to identify the message in replies or notification 178 messages. 180 o Data: Type specific message contents. 182 o End Marker: A 32-bit message end marker that must be set to 183 0x9FACADE9. The End Marker is used by the receiver to validate 184 that it has correctly parsed or skipped a message and provides a 185 method to detect formatting errors. Note that message data may 186 also contain this marker, and that the marker itself is not 187 sufficient for parsing the message. 189 The base message format does not indicate how the peer should deal 190 with the message in cases where the message type is not supported/ 191 understood. This is best dealt with by the application. For 192 example, in case an error notification is returned, or an expected 193 acknowledgement message is not received, the application might choose 194 various courses of action; from simply logging that the feature is 195 not supported, all the way to tearing the relationship with the peer 196 down for the feature, or for all LISP features. 198 4. Session Establishment 200 To ensure backwards compatibility, the map server and ETR MUST 201 communicate via unreliable UDP messages until a TCP session between 202 the two is successfully established. 204 The map server authenticates the ETR with the authentication data 205 contained in the first UDP map-register message it receives from the 206 ETR. Once the ETR is authenticated, the map server performs a 207 passive open by listening on TCP port 4342, and does not qualify the 208 remote port. As a security measure, the map server accepts TCP 209 connections only from those ETRs that have been authenticated via UDP 210 map-register messages. 212 The ETR assumes the active role of the TCP session establishment by 213 connecting to the map server once it has received a UDP map-notify 214 message. 216 When a TCP session goes down, UDP authentication must take place 217 before a new TCP session is established. The map-server will not 218 accept a connection from the ETR until a UDP map-register has been 219 received. Similarly, the ETR will not attempt to establish a session 220 with the map server until an UDP map-notify message has been 221 received. 223 A single reliable transport session is established between the map 224 server and the ETR to cover all communication needs. For example, an 225 ETR that has EID prefix registrations for multiple EID instances and 226 EID address families will only establish a single session with the 227 map server. 229 5. Error Notifications 231 The error notification message is used to communicate base reliable 232 transport session communication errors. LISP applications making use 233 of the reliable transport session and having to communicate 234 application specific errors must define their own messages to do so. 235 An error notification is issued when the receiver of a message does 236 not recognize the message type or cannot parse the message contents. 238 The notification includes the offending message type and ID and as 239 much of the offending message data as the notification sender wishes 240 to. 242 0 1 2 3 243 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 1 244 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 245 | Type = 16 | Length | 246 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 247 | Message ID | 248 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 249 | Error Code | Reserved | 250 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 251 | Offending Message Type | Offending Message Length | 252 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 253 | Offending Message ID | 254 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 255 | Offending Message Data ... 256 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 257 | Message End Marker | 258 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 260 Error Notification message format 262 o Error Code: An 8 bit field identifying the type of error that 263 occurred. Defined errors are: 265 * Unrecognized message type. 267 * Message format error. 269 o Reserved: Set to zero by the sender and ignored by the receiver. 271 o Offending Message Type: 16 bit type field identifying the message 272 type of the offending message that triggered this error 273 notification. This is copied from the Type field of the offending 274 message. 276 o Offending Message Length: 16 bit field that provides the total 277 size of the offending message in octets. This is copied from the 278 Length field of the offending message. 280 o Offending Message ID: A 32-bit field that is set to the Message ID 281 field of the offending message. 283 o Offending Message Data: The Data from the offending message that 284 triggered this error notification. The sender of the notification 285 may include as much of the original data as is deemed necessary. 287 The length of the Offending Message Data field is not provided by 288 the Offending Message Length field and is determined by 289 subtracting the size of the other fields in the message from the 290 Length field. It is valid to not include any of the offending 291 message data when sending an error notification. 293 o End Marker: A 32-bit message end marker that must be set to 294 0x9FACADE9. The End Marker is used by the receiver to validate 295 that it has correctly parsed or skipped a message and provides a 296 method to detect formatting errors. Note that message data may 297 also contain this marker, and that the marker itself is not 298 sufficient for parsing the message. 300 An error notification cannot be the offending message in another 301 error notification and MUST NOT trigger such a message. 303 6. EID Prefix Registration 305 EID prefix registration uses the reliable transport session between 306 an ETR and a Map-Server to communicate the ETR local EID database EID 307 to RLOC mappings to the Map-Server. In contrast to the UDP based 308 periodic registration, mapping information over the reliable 309 transport session is only sent when there is new information 310 available for the Map-Server. The Map-Server does not maintain a 311 timer to expire registrations communicated over the reliable 312 transport session. Instead an explicit de-registration (a 313 registration carrying a zero TTL) is needed to delete the state 314 maintained by the Map-Server. 316 The key used to identify registration mapping records in the ETR to 317 Map-Server communication is the EID prefix. The prefix may be 318 specified using an LCAF encoding that includes an EID instance ID. 320 When the reliable transport session goes down, registration mappings 321 learned by the Map-Server are treated as periodic UDP registrations 322 and a timer is used to expire them after 3 minutes. During this 323 period UDP based registrations or the re-establishment of the 324 reliable transport session and subsequent communication of a new 325 mapping can update the EID prefix mapping state. 327 6.1. Reliable Mapping Registration Messages 329 This section defines the LISP reliable transport session messages 330 used to communicate local EID database registrations between the ETR 331 and the Map-Server. 333 6.1.1. Registration Message 335 The reliable transport registration message is used to communicate 336 EID to RLOC mapping registrations from the ETR to the Map-Server. To 337 increase code reuse, the "Message Data" field uses the same format as 338 the UDP Map-Registers but without the IP and UDP headers. A reliable 339 registration message MUST contain a single mapping-record. The map 340 server MUST discard any reliable registration message that contains 341 more than one mapping record. 343 The reliable transport session is authenticated by means of the 344 session establishment procedure. Thus, although the Map-Register 345 MUST carry the authentication data, it is up to the map server to 346 determine if each individual reliable registration message should be 347 authenticated. 349 0 1 2 3 350 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 1 351 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 352 | Type = 17 | Length | 353 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 354 | Message ID | 355 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 356 | Map-Register message ... 357 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 358 ... Map-Register message | 359 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 360 | Message End Marker | 361 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 363 Registration message format 365 6.1.2. Registration Acknowledgement Message 367 The Acknowledgement message is sent from the Map-Server to the ETR to 368 confirm successful registration of an EID prefix previously 369 communicated by a reliable transport session Registration message. 370 The Registration Acknowledgement message does not carry a mapping 371 record (the map servers view of the mapping). This is accomplished 372 by the LISP reliable transport Map Notification message. 374 0 1 2 3 375 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 1 376 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 377 | Type = 18 | Length | 378 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 379 | Message ID | 380 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 381 | Prefix-Length | EID-Prefix-AFI | EID-Prefix ... 382 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 383 | Message End Marker | 384 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 386 Registration Acknowledgement message format 388 o Prefix-Length: Mask length for the EID prefix. 390 o EID-Prefix AFI: Address family identifier for the EID prefix in 391 the following field. 393 o EID-Prefix: The EID prefix from the received Registration. 395 6.1.3. Registration Rejection Message 397 The Registration Rejection Message is sent by the map server to the 398 ETR to indicate that the registration of a specific EID prefix is 399 being rejected or withdrawn. A rejection refers to a recently-sent 400 registration that is being immediately rejected. A withdrawal refers 401 to a previously accepted registration that is no longer acceptable, 402 perhaps due to a configuration change in the map-server. The ETR 403 must keep track of rejected EID prefixes and be prepared to re- 404 register their mappings when requested through a registration refresh 405 message. 407 0 1 2 3 408 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 1 409 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 410 | Type = 19 | Length | 411 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 412 | Message ID | 413 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 414 | Reason | Reserved | Prefix-Length | 415 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 416 | EID-Prefix-AFI | EID-Prefix ... 417 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 418 | Message End Marker | 419 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 421 Registration Rejection message format 423 o Reason: Code identifying the reason for which the Map-Server 424 rejected or withdrew the registration. 426 * 1 - Not a valid site EID prefix. 428 * 2 - Authentication failure. 430 * 3 - Locator set not allowed. 432 * 4 - Used to cover reason that's not defined. 434 o Reserved: This field is reserved for future use. Set to zero by 435 the sender and ignored by the receiver. 437 o Prefix-Length: Mask length for the EID prefix. 439 o EID-Prefix-AFI: Address family identifier for the EID prefix in 440 the following field. 442 o EID-Prefix: The EID prefix being rejected or withdrawn. 444 6.1.4. Registration Refresh Message 446 Sent by the Map-Server to the ETR to request the (re-)transmission of 447 EID prefix database mapping Registration messages. 449 0 1 2 3 450 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 1 451 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 452 | Type = 20 | Length | 453 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 454 | Message ID | 455 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 456 | Scope |R| Reserved | Prefix-Length | 457 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 458 | EID-Prefix-AFI | EID-Prefix ... 459 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 460 | Message End Marker | 461 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 463 Registration Refresh message format 465 o Scope: Determines the set of registrations being refreshed. 467 * 0 - All prefixes under all address families under all EID 468 instances are being refreshed. When using this scope the 469 Prefix-Length, EID-Prefix-AFI, and EID-Prefix fields MUST be 470 omitted. That is, the Message End Marker follows immediately 471 after the Reserved field. The total length of the message MUST 472 be 15 bytes. 474 * 1 - All prefixes under all address families under a single EID 475 instance are being refreshed. The Prefix-Length MUST be set to 476 zero, EID-Prefix-AFI MUST be set to LCAF type, the EID-Prefix 477 encodes the LCAF Instance ID, the LCAF address AFI MUST be set 478 to UNSPECIFIED. The total length of the message MUST be 30 479 bytes. 481 * 2 - All prefixes under a single address family under a single 482 EID instance are being refreshed. The Prefix-Length MUST be 483 set to zero, the EID-Prefix-AFI MUST be set to LCAF type and 484 the EID-Prefix MUST encode the Instance ID. The LCAF address 485 AFI MUST specify the address family to refresh, the actual 486 address SHOULD be set to zero. 488 * 3 - All prefixes covered by a specific EID prefix in a single 489 EID instance is being refreshed. The Prefix-Length, EID- 490 Prefix-AFI and EID prefix MUST be encoded accordingly. 492 * 4 - A specific EID prefix in a single EID instance is being 493 refreshed. The Prefix-Length, EID-Prefix-AFI and EID prefix 494 MUST be encoded accordingly. 496 The map-server has the flexibility to control the granularity of 497 the refresh by issuing refresh with different scopes. It can send 498 a single refresh with a coarse scope or send individual refreshes 499 with narrower scope. The ETR MUST be able to process all scopes 500 to ensure the map-server registration states are synchronized with 501 the ETR. 503 o R: Request from the ETR to only refresh registrations that have 504 been previously rejected by the Map-Server. If the R bit is set 505 then the scope cannot have a value of 3 and the EID-Prefix and 506 Prefix-Length fields must be omitted. 508 o Reserved: This field is reserved for future use. Set to zero by 509 the sender and ignored by the receiver. 511 o Prefix-Length: Mask length for the EID prefix. Refer to scope for 512 more details. 514 o EID-Prefix-AFI: Address family identifier for the EID prefix in 515 the following field. Refer to scope for more details. 517 o EID-Prefix: The EID prefix being refreshed. Refer to scope for 518 more details. 520 6.1.5. Mapping Notification Message 522 Mapping Notification messages communicate the Map-Server view of the 523 mapping for an EID prefix and no longer serve as a registration 524 acknowledgement. Mapping Notifications do not need message level 525 authentication as they are received over a reliable transport session 526 to a known Map-Server. Note that reliable transport Mapping 527 Notification messages do not reuse the UDP Map-Notify message format. 529 0 1 2 3 530 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 1 531 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 532 | Type = 21 | Length | 533 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 534 | Message ID | 535 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 536 | xTR-ID 128 bits ... 537 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 538 | xTR-ID 128 bits ... 539 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 540 | xTR-ID 128 bits ... 541 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 542 | xTR-ID 128 bits | 543 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 544 | site-ID 64 bits ... 545 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 546 | site-ID 64 bits | 547 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 548 | Mapping Record ... 549 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 550 ... Mapping Record | 551 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 552 | Message End Marker | 553 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 555 Mapping Notification message format 557 o xTR-ID: xTR-ID taken from the last valid registration the map- 558 server received for the EID-prefix conveyed in the mapping record. 560 o site-ID: site-ID taken from the last valid registration the map- 561 server received for the EID-prefix conveyed in the mapping record. 563 o Mapping Record: Mapping record of the EID-prefix the map-server is 564 conveying to the ETR. 566 6.2. ETR Behavior 568 The ETR operates the following per EID prefix, per MS state machine 569 that defines the reliable transport EID prefix registration behavior. 571 There are five states: 573 o No state: The local EID database prefix does not exist. 575 o Periodic: The local EID database prefix is being periodically 576 registered through UDP Map-Register messages as specified in []. 578 o Stable: From the ETR's perspective, no registrations are due to be 579 sent to the peer. The session to the peer is up, and the peer has 580 either acknowledged the registration, or is expected to request a 581 refresh in the future. 583 o AckWait: A Registration message for the prefix has been 584 transmitted to the Map-Server and the ETR is waiting for either a 585 Registration Acknowledge or Registration Rejected reply from the 586 Map-Server. 588 o Reject: The reliable transport registration for the local EID 589 database prefix was rejected by the Map-Server. From the ETR's 590 perspective, no registration is due to the peer AND the peer is 591 known to have rejected the registration. 593 The following events drive the state transitions: 595 o DB creation: The local EID database entry for the EID prefix is 596 created. 598 o DB deletion: The local EID database entry for the EID prefix is 599 deleted. 601 o DB change: The mapping contents or authentication information for 602 the local EID database entry changes. 604 o Session up: The reliable transport session to the Map-Server is 605 established. 607 o Session down: The reliable transport session the Map-Server goes 608 down. 610 o Recv Refresh: A Registration refresh message is received from the 611 Map-Server. 613 o Recv ACK: A Registration Acknowledge message is received from the 614 Map-Server. 616 o Recv Rejected: A Registration Rejected message is received from 617 the Map-Server. 619 o Periodic timer: The timer that drives generation of periodic UDP 620 Map-Register messages fires. 622 The state machine is: 624 +--------------------+--------------------------------------+ 625 | | Prev State | 626 | Event +-------------------+------------------+ 627 | | No state | Periodic | 628 +--------------------+-------------------+------------------+ 629 | DB creation | -> Periodic | N/A | 630 | [session down] | A1 | | 631 +--------------------+-------------------+------------------+ 632 | DB creation | -> AckWait | N/A | 633 | [session up] | A2 | | 634 +--------------------+-------------------+------------------+ 635 | DB deletion | N/A | -> No state | 636 | | | A3 | 637 +--------------------+-------------------+------------------+ 638 | DB change | N/A | - | 639 | | | A1 | 640 +--------------------+-------------------+------------------+ 641 | Session up | - | -> Stable | 642 | | | A4 | 643 +--------------------+-------------------+------------------+ 644 | Session down | - | N/A | 645 | | | | 646 +--------------------+-------------------+------------------+ 647 | Recv Refresh | - | N/A | 648 | | | | 649 +--------------------+-------------------+------------------+ 650 | Recv Refresh | - | N/A | 651 | [rejected] | | | 652 +--------------------+-------------------+------------------+ 653 | Recv ACK | - | N/A | 654 | | | | 655 +--------------------+-------------------+------------------+ 656 | Recv Rejection | - | N/A | 657 | | | | 658 +--------------------+-------------------+------------------+ 659 | Timer | N/A | - | 660 | | | A5 | 661 +--------------------+-------------------+------------------+ 663 xTR per EID prefix per MS state machine 665 +-----------------+-----------------------------------------------+ 666 | | Prev State | 667 | Event +---------------+---------------+---------------+ 668 | | Stable | AckWait | Rejected | 669 +-----------------+---------------+---------------+---------------+ 670 | DB creation | N/A | N/A | N/A | 671 | | | | | 672 +-----------------+---------------+---------------+---------------+ 673 | DB deletion | -> No state | -> No state | -> No state | 674 | | A6 | A6 | | 675 +-----------------+---------------+---------------+---------------+ 676 | DB change | -> AckWait | - | -> AckWait | 677 | | A2 | A2 | A2 | 678 +-----------------+---------------+---------------+---------------+ 679 | Session up | N/A | N/A | N/A | 680 | | | | | 681 +-----------------+---------------+---------------+---------------+ 682 | Session down | -> Periodic | -> Periodic | -> Periodic | 683 | | A7 | A7 | A7 | 684 +-----------------+---------------+---------------+---------------+ 685 | Recv Refresh | -> AckWait | - | -> AckWait | 686 | | A2 | A2 | A2 | 687 +-----------------+---------------+---------------+---------------+ 688 | Recv Refresh | - | - | -> AckWait | 689 | [rejected] | | A2 | A2 | 690 +-----------------+---------------+---------------+---------------+ 691 | Recv ACK | - | -> Stable | -> AckWait | 692 | | | | A2 | 693 +-----------------+---------------+---------------+---------------+ 694 | Recv Rejection | -> Rejected | -> Rejected | - | 695 | | | | | 696 +-----------------+---------------+---------------+---------------+ 697 | Timer | N/A | N/A | N/A | 698 | | | | | 699 +-----------------+---------------+---------------+---------------+ 701 xTR per EID prefix per MS state machine 703 Action descriptions: 705 o A1: Start periodic registration timer with zero delay. 707 o A2: Send Registration over reliable transport session. 709 o A3: Send UDP registration with zero TTL. 711 o A4: Stop periodic registration timer. 713 o A7: Send UDP registration and start periodic registration timer 714 with registration period. 716 o A6: Send Registration with TTL zero over reliable transport 717 session. 719 o A7: Start periodic registration timer with registration period. 721 All timer start actions must be jittered. 723 When the reliable transport session is established the ETR moves the 724 state machine into the Stable state without first registering the EID 725 prefix over the reliable transport session. The map server will send 726 a refresh message with a scope of 0 that will trigger the 727 registration message to be sent. Because other applications may be 728 using the reliable session, the refresh message signals the ETR that 729 the map server supports reliable map registration messages. This 730 model will also allow future optimizations where the Map-Server may 731 retain registration state from a previous instantiation of the 732 reliable transport session with the ETR and only request the refresh 733 of EID prefix state beyond some negotiated session progress marker. 735 Aa Map-Server authentication key change is treated as a DB change 736 event and will result in triggering a new Registration message to be 737 transmitted. 739 6.3. Map-Server Behavior 741 Received registrations create/update or delete mapping state. 743 A refresh with global scope is sent when a session between the ETR 744 and map-server is first established so the map-server can obtain the 745 complete database contents from the ETR. This refresh is also 746 serving as a capability signaling from the map-server to the ETR that 747 it can support reliable registration. 749 Refresh for rejected registrations sent (R bit set) when a new EID 750 prefix is configured on the Map-Server. 752 Refresh is sent whenever authentication key is changed or EID prefix 753 is deconfigured. Upon reception of the registration map-server can 754 decide whether to acknowledge the registration or issue rejection. 756 Mapping Notification message sent whenever the mapping for a 757 registered or more specific prefix for which notifications are 758 requested changes. ETR acknowledgement or rejection messaging for 759 Mapping Notification is not required because the ETR decides how to 760 process the message based on the registered mapping information. If 761 the mapping information changes the resulting registration will 762 trigger a new Mapping Notification message from the Map-Server. 764 7. Security Considerations 766 The LISP reliable transport session SHOULD be authenticated. On 767 controlled RLOC networks that can guarantee that the source RLOC 768 address of data packets cannot be spoofed, the authentication check 769 can be a source address validation on the reliable transport packets. 770 When the RLOC network does not provide such guarantees, reliable 771 transport authentication SHOULD be used. Implementations SHOULD 772 support the TCP Authentication Option (TCP-AO) [RFC5925] and SCTP 773 Authenticated Chunks [RFC4895]. 775 8. IANA Considerations 777 8.1. LISP Reliable Transport Message Types 779 Assignment of new LISP reliable transport message types is done 780 according to the "IETF Review" model defined in [RFC5266]. 782 The initial content of the registry should be as follows. 784 Type Name Reference 785 ----------- ---------------------------------------- -------------- 786 0-15 Reserved This document 787 16 Error Notification This document 788 17 Registration Message This document 789 18 Registration Acknowledgement Message This document 790 19 Registration Rejected Message This document 791 20 Registration Refresh Message This document 792 21 Mapping Notification Message This document 793 22-30 Reserved for EID membership distribution TBD 794 31-64999 Unassigned 795 65000-65535 Reserved for Experimental Use 797 8.2. Transport Protocol Port Numbers 799 TCP port 4342 already reserved for LISP CONS that is now obsolete. 800 Repurpose for reliable transport over TCP. Reserve an SCTP port. 802 9. Acknowledgments 804 The authors would like to thank Noel Chiappa, Dino Farinacci, Jesper 805 Skriver, Andre Pelletier and Les Ginsberg for their contributions to 806 this document. 808 10. Normative References 810 [I-D.ietf-lisp-lcaf] 811 Farinacci, D., Meyer, D., and J. Snijders, "LISP Canonical 812 Address Format (LCAF)", draft-ietf-lisp-lcaf-14 (work in 813 progress), July 2016. 815 [I-D.kouvelas-lisp-reliable-transport] 816 Cassar, C., Kouvelas, I., and D. Lewis, "LISP Reliable 817 Transport", draft-kouvelas-lisp-reliable-transport-02 818 (work in progress), March 2015. 820 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 821 Requirement Levels", BCP 14, RFC 2119, 822 DOI 10.17487/RFC2119, March 1997, 823 . 825 [RFC5266] Devarapalli, V. and P. Eronen, "Secure Connectivity and 826 Mobility Using Mobile IPv4 and IKEv2 Mobility and 827 Multihoming (MOBIKE)", BCP 136, RFC 5266, 828 DOI 10.17487/RFC5266, June 2008, 829 . 831 [RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The 832 Locator/ID Separation Protocol (LISP)", RFC 6830, 833 DOI 10.17487/RFC6830, January 2013, 834 . 836 [RFC6833] Fuller, V. and D. Farinacci, "Locator/ID Separation 837 Protocol (LISP) Map-Server Interface", RFC 6833, 838 DOI 10.17487/RFC6833, January 2013, 839 . 841 Authors' Addresses 843 Chris Cassar 844 Cisco Systems 845 10 New Square Park 846 Bedfont Lakes, Feltham TW14 8HA 847 United Kingdom 849 Email: ccassar@cisco.com 850 Isidor Kouvelas 851 Arista Networks Inc. 852 5453 Great America Parkway 853 Santa Clara, CA 95054 854 USA 856 Email: kouvelas@cisco.com 858 Darrel Lewis 859 Cisco Systems 860 Tasman Drive 861 San Jose, CA 95134 862 USA 864 Email: darlewis@cisco.com 866 Jesus Arango 867 Cisco Systems 868 Tasman Drive 869 San Jose, CA 95134 870 USA 872 Email: jearango@cisco.com 874 Johnson Leong 875 Cisco Systems 876 Tasman Drive 877 San Jose, CA 95134 878 USA 880 Email: joleong@cisco.com