idnits 2.17.1 draft-kouvelas-lisp-map-server-reliable-transport-04.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 25, 2017) is 2405 days in the past. Is this intentional? Checking references for intended status: Experimental ---------------------------------------------------------------------------- == Missing Reference: 'RFC5925' is mentioned on line 769, but not defined == Missing Reference: 'RFC4895' is mentioned on line 770, but not defined == Unused Reference: 'RFC6830' is defined on line 818, but no explicit reference was found in the text ** Obsolete normative reference: RFC 6830 (Obsoleted by RFC 9300, RFC 9301) ** Obsolete normative reference: RFC 6833 (Obsoleted by RFC 9301) Summary: 2 errors (**), 0 flaws (~~), 4 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 J. Leong 4 Intended status: Experimental D. Lewis 5 Expires: March 29, 2018 Cisco Systems 6 I. Kouvelas 7 Arista Networks Inc. 8 J. Arango 9 Microsoft 10 September 25, 2017 12 LISP Map Server Reliable Transport 13 draft-kouvelas-lisp-map-server-reliable-transport-04.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 Status of This Memo 30 This Internet-Draft is submitted in full conformance with the 31 provisions of BCP 78 and BCP 79. 33 Internet-Drafts are working documents of the Internet Engineering 34 Task Force (IETF). Note that other groups may also distribute 35 working documents as Internet-Drafts. The list of current Internet- 36 Drafts is at http://datatracker.ietf.org/drafts/current/. 38 Internet-Drafts are draft documents valid for a maximum of six months 39 and may be updated, replaced, or obsoleted by other documents at any 40 time. It is inappropriate to use Internet-Drafts as reference 41 material or to cite them other than as "work in progress." 43 This Internet-Draft will expire on March 29, 2018. 45 Copyright Notice 47 Copyright (c) 2017 IETF Trust and the persons identified as the 48 document authors. All rights reserved. 50 This document is subject to BCP 78 and the IETF Trust's Legal 51 Provisions Relating to IETF Documents 52 (http://trustee.ietf.org/license-info) in effect on the date of 53 publication of this document. Please review these documents 54 carefully, as they describe your rights and restrictions with respect 55 to this document. Code Components extracted from this document must 56 include Simplified BSD License text as described in Section 4.e of 57 the Trust Legal Provisions and are provided without warranty as 58 described in the Simplified BSD License. 60 Table of Contents 62 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 63 2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 3 64 3. Message Format . . . . . . . . . . . . . . . . . . . . . . . 4 65 4. Session Establishment . . . . . . . . . . . . . . . . . . . . 5 66 5. Error Notifications . . . . . . . . . . . . . . . . . . . . . 5 67 6. EID Prefix Registration . . . . . . . . . . . . . . . . . . . 7 68 6.1. Reliable Mapping Registration Messages . . . . . . . . . 7 69 6.1.1. Registration Message . . . . . . . . . . . . . . . . 8 70 6.1.2. Registration Acknowledgement Message . . . . . . . . 8 71 6.1.3. Registration Rejection Message . . . . . . . . . . . 9 72 6.1.4. Registration Refresh Message . . . . . . . . . . . . 10 73 6.1.5. Mapping Notification Message . . . . . . . . . . . . 12 74 6.2. ETR Behavior . . . . . . . . . . . . . . . . . . . . . . 13 75 6.3. Map-Server Behavior . . . . . . . . . . . . . . . . . . . 17 76 7. Security Considerations . . . . . . . . . . . . . . . . . . . 18 77 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 78 8.1. LISP Reliable Transport Message Types . . . . . . . . . . 18 79 8.2. Transport Protocol Port Numbers . . . . . . . . . . . . . 18 80 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 81 10. Normative References . . . . . . . . . . . . . . . . . . . . 19 82 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19 84 1. Introduction 86 The communication channel between LISP ETRs and Map-Servers is based 87 on unreliable UDP message exchange [RFC6833]. Where required, 88 reliability is pursued through periodic retransmissions that maintain 89 soft state on the peer. Map-Register messages are retransmitted 90 every minute by an ETR and the Map-Server times out its state if the 91 state is not refreshed for three successive periods. When 92 registering multiple EID-Prefixes, the ETR includes multiple mapping 93 records in the Map-Register message. Packet size limitations provide 94 an upper bound to the number of mapping records that can be placed in 95 each Map-Register message. When the ETR has more EID-Prefixes to 96 register than can be packed in a single Map-Register message, the 97 mapping records for the EID-Prefixes are split across multiple Map- 98 Register messages. 100 The drawback of the periodic registration is the constant load that 101 it introduces on both the ETR and the Map-Server. The ETR uses 102 resources to periodically build and transmit the Map-Register 103 messages, and to process the resulting Map-Notify messages issued by 104 the Map-Server. The Map-Server uses resources to process the 105 received Map-Register messages, update the corresponding registration 106 state, and build and transmit the matching Map-Notify messages. When 107 the number of EID-Prefixes to be registered by an ETR is small, the 108 resulting load imposed by periodic registrations may not be 109 significant. The ETR will only transmit a single Map-Register 110 message each period that contains a small number of mapping records. 112 In some LISP deployments, a large set of EID-Prefixes must be 113 registered by each ETR (e.g. mobility, database redistribution). Use 114 cases with a large set of EID-Prefixes behind an ETR will result in a 115 much higher load. An example is LISP mobility deployments where EID- 116 Prefixes are limited to host entries. ETRs may have thousands of 117 hosts to register resulting in hundreds of Map-Register and Map- 118 Notify messages per registration period. 120 A transport is required for the ETR to Map-Server communication that 121 provides reliability, flow-control and endpoint liveness 122 notifications. This document describes the use of TCP or SCTP as a 123 LISP reliable transport. The initial application for the LISP 124 reliable transport session is the support of scalable EID prefix 125 registration. The reliable session mechanism is defined to be 126 extensible so that it can support additional LISP communication 127 requirements as they arise using a single reliable transport session 128 between an ETR and a Map-Server. The use of the reliable transport 129 session for EID prefix registration is an alternative and does not 130 replace the existing UDP based mechanism. 132 2. Requirements Notation 134 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 135 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 136 document are to be interpreted as described in [RFC2119]. 138 3. Message Format 140 A single LISP reliable transport session may carry information for 141 multiple LISP applications. One such application is the registration 142 of EID to RLOC mappings that operates over a session between an ETR 143 and a Map-Server. Communication over a session is based on the 144 exchange of messages. This document defines a base set of messages 145 to support session establishment and management. It also defines the 146 messages for the EID to RLOC mapping registration application. 148 To support protocol extensibility when new applications, or 149 extensions to existing applications are introduced, the messages are 150 based on a TLV format. 152 0 1 2 3 153 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 1 154 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 155 | Type | Length | 156 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 157 | Message ID | 158 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 159 | Message Data ... 160 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 161 | Message End Marker | 162 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 164 Reliable transport message format 166 o Type: 16 bit type field identifying the message type. 168 o Length: 16 bit field that provides the total size of the message 169 in octets including the length, type and end marker fields. The 170 length allows the receiver to locate the next message in the TCP 171 stream. The minimum value of the length field is 8. 173 o ID: A 32-bit value that identifies the message. May be used by 174 the receiver to identify the message in replies or notification 175 messages. 177 o Data: Type specific message contents. 179 o End Marker: A 32-bit message end marker that must be set to 180 0x9FACADE9. The End Marker is used by the receiver to validate 181 that it has correctly parsed or skipped a message and provides a 182 method to detect formatting errors. Note that message data may 183 also contain this marker, and that the marker itself is not 184 sufficient for parsing the message. 186 The base message format does not indicate how the peer should deal 187 with the message in cases where the message type is not supported/ 188 understood. This is best dealt with by the application. For 189 example, in case an error notification is returned, or an expected 190 acknowledgement message is not received, the application might choose 191 various courses of action; from simply logging that the feature is 192 not supported, all the way to tearing the relationship with the peer 193 down for the feature, or for all LISP features. 195 4. Session Establishment 197 To ensure backwards compatibility, the map server and ETR MUST 198 communicate via unreliable UDP messages until a TCP session between 199 the two is successfully established. 201 The map server authenticates the ETR with the authentication data 202 contained in the first UDP map-register message it receives from the 203 ETR. Once the ETR is authenticated, the map server performs a 204 passive open by listening on TCP port 4342, and does not qualify the 205 remote port. As a security measure, the map server accepts TCP 206 connections only from those ETRs that have been authenticated via UDP 207 map-register messages. 209 The ETR assumes the active role of the TCP session establishment by 210 connecting to the map server once it has received a UDP map-notify 211 message. 213 When a TCP session goes down, UDP authentication must take place 214 before a new TCP session is established. The map-server will not 215 accept a connection from the ETR until a UDP map-register has been 216 received. Similarly, the ETR will not attempt to establish a session 217 with the map server until an UDP map-notify message has been 218 received. 220 A single reliable transport session is established between the map 221 server and the ETR to cover all communication needs. For example, an 222 ETR that has EID prefix registrations for multiple EID instances and 223 EID address families will only establish a single session with the 224 map server. 226 5. Error Notifications 228 The error notification message is used to communicate base reliable 229 transport session communication errors. LISP applications making use 230 of the reliable transport session and having to communicate 231 application specific errors must define their own messages to do so. 232 An error notification is issued when the receiver of a message does 233 not recognize the message type or cannot parse the message contents. 235 The notification includes the offending message type and ID and as 236 much of the offending message data as the notification sender wishes 237 to. 239 0 1 2 3 240 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 1 241 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 242 | Type = 16 | Length | 243 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 244 | Message ID | 245 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 246 | Error Code | Reserved | 247 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 248 | Offending Message Type | Offending Message Length | 249 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 250 | Offending Message ID | 251 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 252 | Offending Message Data ... 253 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 254 | Message End Marker | 255 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 257 Error Notification message format 259 o Error Code: An 8 bit field identifying the type of error that 260 occurred. Defined errors are: 262 * Unrecognized message type. 264 * Message format error. 266 o Reserved: Set to zero by the sender and ignored by the receiver. 268 o Offending Message Type: 16 bit type field identifying the message 269 type of the offending message that triggered this error 270 notification. This is copied from the Type field of the offending 271 message. 273 o Offending Message Length: 16 bit field that provides the total 274 size of the offending message in octets. This is copied from the 275 Length field of the offending message. 277 o Offending Message ID: A 32-bit field that is set to the Message ID 278 field of the offending message. 280 o Offending Message Data: The Data from the offending message that 281 triggered this error notification. The sender of the notification 282 may include as much of the original data as is deemed necessary. 284 The length of the Offending Message Data field is not provided by 285 the Offending Message Length field and is determined by 286 subtracting the size of the other fields in the message from the 287 Length field. It is valid to not include any of the offending 288 message data when sending an error notification. 290 o End Marker: A 32-bit message end marker that must be set to 291 0x9FACADE9. The End Marker is used by the receiver to validate 292 that it has correctly parsed or skipped a message and provides a 293 method to detect formatting errors. Note that message data may 294 also contain this marker, and that the marker itself is not 295 sufficient for parsing the message. 297 An error notification cannot be the offending message in another 298 error notification and MUST NOT trigger such a message. 300 6. EID Prefix Registration 302 EID prefix registration uses the reliable transport session between 303 an ETR and a Map-Server to communicate the ETR local EID database EID 304 to RLOC mappings to the Map-Server. In contrast to the UDP based 305 periodic registration, mapping information over the reliable 306 transport session is only sent when there is new information 307 available for the Map-Server. The Map-Server does not maintain a 308 timer to expire registrations communicated over the reliable 309 transport session. Instead an explicit de-registration (a 310 registration carrying a zero TTL) is needed to delete the state 311 maintained by the Map-Server. 313 The key used to identify registration mapping records in the ETR to 314 Map-Server communication is the EID prefix. The prefix may be 315 specified using an LCAF encoding that includes an EID instance ID. 317 When the reliable transport session goes down, registration mappings 318 learned by the Map-Server are treated as periodic UDP registrations 319 and a timer is used to expire them after 3 minutes. During this 320 period UDP based registrations or the re-establishment of the 321 reliable transport session and subsequent communication of a new 322 mapping can update the EID prefix mapping state. 324 6.1. Reliable Mapping Registration Messages 326 This section defines the LISP reliable transport session messages 327 used to communicate local EID database registrations between the ETR 328 and the Map-Server. 330 6.1.1. Registration Message 332 The reliable transport registration message is used to communicate 333 EID to RLOC mapping registrations from the ETR to the Map-Server. To 334 increase code reuse, the "Message Data" field uses the same format as 335 the UDP Map-Registers but without the IP and UDP headers. A reliable 336 registration message MUST contain a single mapping-record. The map 337 server MUST discard any reliable registration message that contains 338 more than one mapping record. 340 The reliable transport session is authenticated by means of the 341 session establishment procedure. Thus, although the Map-Register 342 MUST carry the authentication data, it is up to the map server to 343 determine if each individual reliable registration message should be 344 authenticated. 346 0 1 2 3 347 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 1 348 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 349 | Type = 17 | Length | 350 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 351 | Message ID | 352 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 353 | Map-Register message ... 354 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 355 ... Map-Register message | 356 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 357 | Message End Marker | 358 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 360 Registration message format 362 6.1.2. Registration Acknowledgement Message 364 The Acknowledgement message is sent from the Map-Server to the ETR to 365 confirm successful registration of an EID prefix previously 366 communicated by a reliable transport session Registration message. 367 The Registration Acknowledgement message does not carry a mapping 368 record (the map servers view of the mapping). This is accomplished 369 by the LISP reliable transport Map Notification message. 371 0 1 2 3 372 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 1 373 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 374 | Type = 18 | Length | 375 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 376 | Message ID | 377 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 378 | Prefix-Length | EID-Prefix-AFI | EID-Prefix ... 379 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 380 | Message End Marker | 381 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 383 Registration Acknowledgement message format 385 o Prefix-Length: Mask length for the EID prefix. 387 o EID-Prefix AFI: Address family identifier for the EID prefix in 388 the following field. 390 o EID-Prefix: The EID prefix from the received Registration. 392 6.1.3. Registration Rejection Message 394 The Registration Rejection Message is sent by the map server to the 395 ETR to indicate that the registration of a specific EID prefix is 396 being rejected or withdrawn. A rejection refers to a recently-sent 397 registration that is being immediately rejected. A withdrawal refers 398 to a previously accepted registration that is no longer acceptable, 399 perhaps due to a configuration change in the map-server. The ETR 400 must keep track of rejected EID prefixes and be prepared to re- 401 register their mappings when requested through a registration refresh 402 message. 404 0 1 2 3 405 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 1 406 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 407 | Type = 19 | Length | 408 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 409 | Message ID | 410 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 411 | Reason | Reserved | Prefix-Length | 412 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 413 | EID-Prefix-AFI | EID-Prefix ... 414 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 415 | Message End Marker | 416 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 418 Registration Rejection message format 420 o Reason: Code identifying the reason for which the Map-Server 421 rejected or withdrew the registration. 423 * 1 - Not a valid site EID prefix. 425 * 2 - Authentication failure. 427 * 3 - Locator set not allowed. 429 * 4 - Used to cover reason that's not defined. 431 o Reserved: This field is reserved for future use. Set to zero by 432 the sender and ignored by the receiver. 434 o Prefix-Length: Mask length for the EID prefix. 436 o EID-Prefix-AFI: Address family identifier for the EID prefix in 437 the following field. 439 o EID-Prefix: The EID prefix being rejected or withdrawn. 441 6.1.4. Registration Refresh Message 443 Sent by the Map-Server to the ETR to request the (re-)transmission of 444 EID prefix database mapping Registration messages. 446 0 1 2 3 447 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 1 448 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 449 | Type = 20 | Length | 450 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 451 | Message ID | 452 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 453 | Scope |R| Reserved | Prefix-Length | 454 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 455 | EID-Prefix-AFI | EID-Prefix ... 456 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 457 | Message End Marker | 458 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 460 Registration Refresh message format 462 o Scope: Determines the set of registrations being refreshed. 464 * 0 - All prefixes under all address families under all EID 465 instances are being refreshed. When using this scope the 466 Prefix-Length, EID-Prefix-AFI, and EID-Prefix fields MUST be 467 omitted. That is, the Message End Marker follows immediately 468 after the Reserved field. The total length of the message MUST 469 be 15 bytes. 471 * 1 - All prefixes under all address families under a single EID 472 instance are being refreshed. The Prefix-Length MUST be set to 473 zero, EID-Prefix-AFI MUST be set to LCAF type, the EID-Prefix 474 encodes the LCAF Instance ID, the LCAF address AFI MUST be set 475 to UNSPECIFIED. The total length of the message MUST be 30 476 bytes. 478 * 2 - All prefixes under a single address family under a single 479 EID instance are being refreshed. The Prefix-Length MUST be 480 set to zero, the EID-Prefix-AFI MUST be set to LCAF type and 481 the EID-Prefix MUST encode the Instance ID. The LCAF address 482 AFI MUST specify the address family to refresh, the actual 483 address SHOULD be set to zero. 485 * 3 - All prefixes covered by a specific EID prefix in a single 486 EID instance is being refreshed. The Prefix-Length, EID- 487 Prefix-AFI and EID prefix MUST be encoded accordingly. 489 * 4 - A specific EID prefix in a single EID instance is being 490 refreshed. The Prefix-Length, EID-Prefix-AFI and EID prefix 491 MUST be encoded accordingly. 493 The map-server has the flexibility to control the granularity of 494 the refresh by issuing refresh with different scopes. It can send 495 a single refresh with a coarse scope or send individual refreshes 496 with narrower scope. The ETR MUST be able to process all scopes 497 to ensure the map-server registration states are synchronized with 498 the ETR. 500 o R: Request from the ETR to only refresh registrations that have 501 been previously rejected by the Map-Server. If the R bit is set 502 then the scope cannot have a value of 3 and the EID-Prefix and 503 Prefix-Length fields must be omitted. 505 o Reserved: This field is reserved for future use. Set to zero by 506 the sender and ignored by the receiver. 508 o Prefix-Length: Mask length for the EID prefix. Refer to scope for 509 more details. 511 o EID-Prefix-AFI: Address family identifier for the EID prefix in 512 the following field. Refer to scope for more details. 514 o EID-Prefix: The EID prefix being refreshed. Refer to scope for 515 more details. 517 6.1.5. Mapping Notification Message 519 Mapping Notification messages communicate the Map-Server view of the 520 mapping for an EID prefix and no longer serve as a registration 521 acknowledgement. Mapping Notifications do not need message level 522 authentication as they are received over a reliable transport session 523 to a known Map-Server. Note that reliable transport Mapping 524 Notification messages do not reuse the UDP Map-Notify message format. 526 0 1 2 3 527 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 1 528 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 529 | Type = 21 | Length | 530 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 531 | Message ID | 532 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 533 | xTR-ID 128 bits ... 534 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 535 | xTR-ID 128 bits ... 536 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 537 | xTR-ID 128 bits ... 538 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 539 | xTR-ID 128 bits | 540 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 541 | site-ID 64 bits ... 542 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 543 | site-ID 64 bits | 544 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 545 | Mapping Record ... 546 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 547 ... Mapping Record | 548 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 549 | Message End Marker | 550 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 552 Mapping Notification message format 554 o xTR-ID: xTR-ID taken from the last valid registration the map- 555 server received for the EID-prefix conveyed in the mapping record. 557 o site-ID: site-ID taken from the last valid registration the map- 558 server received for the EID-prefix conveyed in the mapping record. 560 o Mapping Record: Mapping record of the EID-prefix the map-server is 561 conveying to the ETR. 563 6.2. ETR Behavior 565 The ETR operates the following per EID prefix, per MS state machine 566 that defines the reliable transport EID prefix registration behavior. 568 There are five states: 570 o No state: The local EID database prefix does not exist. 572 o Periodic: The local EID database prefix is being periodically 573 registered through UDP Map-Register messages as specified in []. 575 o Stable: From the ETR's perspective, no registrations are due to be 576 sent to the peer. The session to the peer is up, and the peer has 577 either acknowledged the registration, or is expected to request a 578 refresh in the future. 580 o AckWait: A Registration message for the prefix has been 581 transmitted to the Map-Server and the ETR is waiting for either a 582 Registration Acknowledge or Registration Rejected reply from the 583 Map-Server. 585 o Reject: The reliable transport registration for the local EID 586 database prefix was rejected by the Map-Server. From the ETR's 587 perspective, no registration is due to the peer AND the peer is 588 known to have rejected the registration. 590 The following events drive the state transitions: 592 o DB creation: The local EID database entry for the EID prefix is 593 created. 595 o DB deletion: The local EID database entry for the EID prefix is 596 deleted. 598 o DB change: The mapping contents or authentication information for 599 the local EID database entry changes. 601 o Session up: The reliable transport session to the Map-Server is 602 established. 604 o Session down: The reliable transport session the Map-Server goes 605 down. 607 o Recv Refresh: A Registration refresh message is received from the 608 Map-Server. 610 o Recv ACK: A Registration Acknowledge message is received from the 611 Map-Server. 613 o Recv Rejected: A Registration Rejected message is received from 614 the Map-Server. 616 o Periodic timer: The timer that drives generation of periodic UDP 617 Map-Register messages fires. 619 The state machine is: 621 +--------------------+--------------------------------------+ 622 | | Prev State | 623 | Event +-------------------+------------------+ 624 | | No state | Periodic | 625 +--------------------+-------------------+------------------+ 626 | DB creation | -> Periodic | N/A | 627 | [session down] | A1 | | 628 +--------------------+-------------------+------------------+ 629 | DB creation | -> AckWait | N/A | 630 | [session up] | A2 | | 631 +--------------------+-------------------+------------------+ 632 | DB deletion | N/A | -> No state | 633 | | | A3 | 634 +--------------------+-------------------+------------------+ 635 | DB change | N/A | - | 636 | | | A1 | 637 +--------------------+-------------------+------------------+ 638 | Session up | - | -> Stable | 639 | | | A4 | 640 +--------------------+-------------------+------------------+ 641 | Session down | - | N/A | 642 | | | | 643 +--------------------+-------------------+------------------+ 644 | Recv Refresh | - | N/A | 645 | | | | 646 +--------------------+-------------------+------------------+ 647 | Recv Refresh | - | N/A | 648 | [rejected] | | | 649 +--------------------+-------------------+------------------+ 650 | Recv ACK | - | N/A | 651 | | | | 652 +--------------------+-------------------+------------------+ 653 | Recv Rejection | - | N/A | 654 | | | | 655 +--------------------+-------------------+------------------+ 656 | Timer | N/A | - | 657 | | | A5 | 658 +--------------------+-------------------+------------------+ 660 xTR per EID prefix per MS state machine 662 +-----------------+-----------------------------------------------+ 663 | | Prev State | 664 | Event +---------------+---------------+---------------+ 665 | | Stable | AckWait | Rejected | 666 +-----------------+---------------+---------------+---------------+ 667 | DB creation | N/A | N/A | N/A | 668 | | | | | 669 +-----------------+---------------+---------------+---------------+ 670 | DB deletion | -> No state | -> No state | -> No state | 671 | | A6 | A6 | | 672 +-----------------+---------------+---------------+---------------+ 673 | DB change | -> AckWait | - | -> AckWait | 674 | | A2 | A2 | A2 | 675 +-----------------+---------------+---------------+---------------+ 676 | Session up | N/A | N/A | N/A | 677 | | | | | 678 +-----------------+---------------+---------------+---------------+ 679 | Session down | -> Periodic | -> Periodic | -> Periodic | 680 | | A7 | A7 | A7 | 681 +-----------------+---------------+---------------+---------------+ 682 | Recv Refresh | -> AckWait | - | -> AckWait | 683 | | A2 | A2 | A2 | 684 +-----------------+---------------+---------------+---------------+ 685 | Recv Refresh | - | - | -> AckWait | 686 | [rejected] | | A2 | A2 | 687 +-----------------+---------------+---------------+---------------+ 688 | Recv ACK | - | -> Stable | -> AckWait | 689 | | | | A2 | 690 +-----------------+---------------+---------------+---------------+ 691 | Recv Rejection | -> Rejected | -> Rejected | - | 692 | | | | | 693 +-----------------+---------------+---------------+---------------+ 694 | Timer | N/A | N/A | N/A | 695 | | | | | 696 +-----------------+---------------+---------------+---------------+ 698 xTR per EID prefix per MS state machine 700 Action descriptions: 702 o A1: Start periodic registration timer with zero delay. 704 o A2: Send Registration over reliable transport session. 706 o A3: Send UDP registration with zero TTL. 708 o A4: Stop periodic registration timer. 710 o A7: Send UDP registration and start periodic registration timer 711 with registration period. 713 o A6: Send Registration with TTL zero over reliable transport 714 session. 716 o A7: Start periodic registration timer with registration period. 718 All timer start actions must be jittered. 720 When the reliable transport session is established the ETR moves the 721 state machine into the Stable state without first registering the EID 722 prefix over the reliable transport session. The map server will send 723 a refresh message with a scope of 0 that will trigger the 724 registration message to be sent. Because other applications may be 725 using the reliable session, the refresh message signals the ETR that 726 the map server supports reliable map registration messages. This 727 model will also allow future optimizations where the Map-Server may 728 retain registration state from a previous instantiation of the 729 reliable transport session with the ETR and only request the refresh 730 of EID prefix state beyond some negotiated session progress marker. 732 Aa Map-Server authentication key change is treated as a DB change 733 event and will result in triggering a new Registration message to be 734 transmitted. 736 6.3. Map-Server Behavior 738 Received registrations create/update or delete mapping state. 740 A refresh with global scope is sent when a session between the ETR 741 and map-server is first established so the map-server can obtain the 742 complete database contents from the ETR. This refresh is also 743 serving as a capability signaling from the map-server to the ETR that 744 it can support reliable registration. 746 Refresh for rejected registrations sent (R bit set) when a new EID 747 prefix is configured on the Map-Server. 749 Refresh is sent whenever authentication key is changed or EID prefix 750 is deconfigured. Upon reception of the registration map-server can 751 decide whether to acknowledge the registration or issue rejection. 753 Mapping Notification message sent whenever the mapping for a 754 registered or more specific prefix for which notifications are 755 requested changes. ETR acknowledgement or rejection messaging for 756 Mapping Notification is not required because the ETR decides how to 757 process the message based on the registered mapping information. If 758 the mapping information changes the resulting registration will 759 trigger a new Mapping Notification message from the Map-Server. 761 7. Security Considerations 763 The LISP reliable transport session SHOULD be authenticated. On 764 controlled RLOC networks that can guarantee that the source RLOC 765 address of data packets cannot be spoofed, the authentication check 766 can be a source address validation on the reliable transport packets. 767 When the RLOC network does not provide such guarantees, reliable 768 transport authentication SHOULD be used. Implementations SHOULD 769 support the TCP Authentication Option (TCP-AO) [RFC5925] and SCTP 770 Authenticated Chunks [RFC4895]. 772 8. IANA Considerations 774 8.1. LISP Reliable Transport Message Types 776 Assignment of new LISP reliable transport message types is done 777 according to the "IETF Review" model defined in [RFC5266]. 779 The initial content of the registry should be as follows. 781 Type Name Reference 782 ----------- ---------------------------------------- -------------- 783 0-15 Reserved This document 784 16 Error Notification This document 785 17 Registration Message This document 786 18 Registration Acknowledgement Message This document 787 19 Registration Rejected Message This document 788 20 Registration Refresh Message This document 789 21 Mapping Notification Message This document 790 22-30 Reserved for EID membership distribution TBD 791 31-64999 Unassigned 792 65000-65535 Reserved for Experimental Use 794 8.2. Transport Protocol Port Numbers 796 TCP port 4342 already reserved for LISP CONS that is now obsolete. 797 Repurpose for reliable transport over TCP. Reserve an SCTP port. 799 9. Acknowledgments 801 The authors would like to thank Noel Chiappa, Dino Farinacci, Jesper 802 Skriver, Andre Pelletier and Les Ginsberg for their contributions to 803 this document. 805 10. Normative References 807 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 808 Requirement Levels", BCP 14, RFC 2119, 809 DOI 10.17487/RFC2119, March 1997, . 812 [RFC5266] Devarapalli, V. and P. Eronen, "Secure Connectivity and 813 Mobility Using Mobile IPv4 and IKEv2 Mobility and 814 Multihoming (MOBIKE)", BCP 136, RFC 5266, 815 DOI 10.17487/RFC5266, June 2008, . 818 [RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The 819 Locator/ID Separation Protocol (LISP)", RFC 6830, 820 DOI 10.17487/RFC6830, January 2013, . 823 [RFC6833] Fuller, V. and D. Farinacci, "Locator/ID Separation 824 Protocol (LISP) Map-Server Interface", RFC 6833, 825 DOI 10.17487/RFC6833, January 2013, . 828 Authors' Addresses 830 Chris Cassar 831 Cisco Systems 832 10 New Square Park 833 Bedfont Lakes, Feltham TW14 8HA 834 United Kingdom 836 Email: ccassar@cisco.com 838 Johnson Leong 839 Cisco Systems 840 Tasman Drive 841 San Jose, CA 95134 842 USA 844 Email: joleong@cisco.com 845 Darrel Lewis 846 Cisco Systems 847 Tasman Drive 848 San Jose, CA 95134 849 USA 851 Email: darlewis@cisco.com 853 Isidor Kouvelas 854 Arista Networks Inc. 855 5453 Great America Parkway 856 Santa Clara, CA 95054 857 USA 859 Email: isidor@kouvelas.net 861 Jesus Arango 862 Microsoft 864 Email: jearango@microsoft.com