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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group Q. Xie 3 Internet-Draft Motorola 4 Intended status: Experimental R. Stewart 5 Expires: May 13, 2007 Cisco Systems, Inc. 6 M. Stillman 7 Nokia 8 M. Tuexen 9 Muenster Univ. of Applied Sciences 10 A. Silverton 11 Motorola, Inc. 12 November 9, 2006 14 Endpoint Handlespace Redundancy Protocol (ENRP) 15 draft-ietf-rserpool-enrp-14.txt 17 Status of this Memo 19 By submitting this Internet-Draft, each author represents that any 20 applicable patent or other IPR claims of which he or she is aware 21 have been or will be disclosed, and any of which he or she becomes 22 aware will be disclosed, in accordance with Section 6 of BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF), its areas, and its working groups. Note that 26 other groups may also distribute working documents as Internet- 27 Drafts. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 The list of current Internet-Drafts can be accessed at 35 http://www.ietf.org/ietf/1id-abstracts.txt. 37 The list of Internet-Draft Shadow Directories can be accessed at 38 http://www.ietf.org/shadow.html. 40 This Internet-Draft will expire on May 13, 2007. 42 Copyright Notice 44 Copyright (C) The Internet Society (2006). 46 Abstract 48 Endpoint Handlespace Redundancy Protocol (ENRP) is designed to work 49 in conjunction with the Aggregate Server Access Protocol (ASAP) to 50 accomplish the functionality of the Reliable Server Pooling 51 (Rserpool) requirements and architecture. Within the operational 52 scope of Rserpool, ENRP defines the procedures and message formats of 53 a distributed, fault-tolerant registry service for storing, 54 bookkeeping, retrieving, and distributing pool operation and 55 membership information. 57 Table of Contents 59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 60 1.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 4 61 1.2. Conventions . . . . . . . . . . . . . . . . . . . . . . . 5 62 2. ENRP Message Definitions . . . . . . . . . . . . . . . . . . . 6 63 2.1. ENRP_PRESENCE message . . . . . . . . . . . . . . . . . . 6 64 2.2. ENRP_HANDLE_TABLE_REQUEST message . . . . . . . . . . . . 8 65 2.3. ENRP_HANDLE_TABLE_RESPONSE message . . . . . . . . . . . . 8 66 2.4. ENRP_HANDLE_UPDATE message . . . . . . . . . . . . . . . . 10 67 2.5. ENRP_LIST_REQUEST message . . . . . . . . . . . . . . . . 11 68 2.6. ENRP_LIST_RESPONSE message . . . . . . . . . . . . . . . . 12 69 2.7. ENRP_INIT_TAKEOVER message . . . . . . . . . . . . . . . . 13 70 2.8. ENRP_INIT_TAKEOVER_ACK message . . . . . . . . . . . . . . 14 71 2.9. ENRP_TAKEOVER_SERVER message . . . . . . . . . . . . . . . 14 72 2.10. ENRP_ERROR message . . . . . . . . . . . . . . . . . . . . 15 73 3. ENRP Operation Procedures . . . . . . . . . . . . . . . . . . 17 74 3.1. Methods for Communicating amongst ENRP Servers . . . . . . 17 75 3.2. ENRP Server Initialization . . . . . . . . . . . . . . . . 18 76 3.2.1. Generate a Server Identifier . . . . . . . . . . . . . 19 77 3.2.2. Acquire Peer Server List . . . . . . . . . . . . . . . 19 78 3.2.3. Download ENRP Handlespace Data from Mentor Peer . . . 21 79 3.3. Handle PE Registration . . . . . . . . . . . . . . . . . . 23 80 3.3.1. Rules on PE Re-registration . . . . . . . . . . . . . 25 81 3.4. Handle PE De-registration . . . . . . . . . . . . . . . . 25 82 3.5. Pool Handle Translation . . . . . . . . . . . . . . . . . 26 83 3.6. Server Handlespace Update . . . . . . . . . . . . . . . . 27 84 3.6.1. Announcing Addition or Update of PE . . . . . . . . . 27 85 3.6.2. Announcing Removal of PE . . . . . . . . . . . . . . . 28 86 3.7. Detecting and Removing Unreachable PE . . . . . . . . . . 28 87 3.8. Helping PE and PU to Discover Home ENRP Server . . . . . . 29 88 3.9. Maintaining Peer List and Monitoring Peer Status . . . . . 30 89 3.9.1. Discovering New Peer . . . . . . . . . . . . . . . . . 30 90 3.9.2. Server Sending Heartbeat . . . . . . . . . . . . . . . 30 91 3.9.3. Detecting Peer Server Failure . . . . . . . . . . . . 30 92 3.10. Taking-over a Failed Peer Server . . . . . . . . . . . . . 31 93 3.10.1. Initiate Server Take-over Arbitration . . . . . . . . 31 94 3.10.2. Take-over Target Peer Server . . . . . . . . . . . . . 32 95 3.11. Handlespace Data Auditing and Re-synchronization . . . . . 33 96 3.11.1. Auditing Procedures . . . . . . . . . . . . . . . . . 33 97 3.11.2. PE Checksum Calculation Algorithm . . . . . . . . . . 34 98 3.11.3. Re-synchronization Procedures . . . . . . . . . . . . 34 99 3.12. Handling Unrecognized Message or Unrecognized Parameter . 35 100 4. Variables and Thresholds . . . . . . . . . . . . . . . . . . . 36 101 4.1. Variables . . . . . . . . . . . . . . . . . . . . . . . . 36 102 4.2. Thresholds . . . . . . . . . . . . . . . . . . . . . . . . 36 103 5. Security Considerations . . . . . . . . . . . . . . . . . . . 37 104 5.1. Implementing Security Mechanisms . . . . . . . . . . . . . 38 105 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 40 106 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 41 107 7.1. Normative References . . . . . . . . . . . . . . . . . . . 41 108 7.2. Informative References . . . . . . . . . . . . . . . . . . 42 109 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 43 110 Intellectual Property and Copyright Statements . . . . . . . . . . 45 112 1. Introduction 114 ENRP is designed to work in conjunction with ASAP [1] to accomplish 115 the functionality of Rserpool as defined by its requirements [2] and 116 architecture [3]. 118 Within the operational scope of Rserpool, ENRP defines the procedures 119 and message formats of a distributed fault-tolerant registry service 120 for storing, bookkeeping, retrieving, and distributing pool operation 121 and membership information. 123 Whenever appropriate, in the rest of this document we will refer to 124 this Rserpool registry service as ENRP handlespace, or simply 125 handlespace. 127 1.1. Definitions 129 This document uses the following terms: 131 Operational scope: See [3]; 133 Pool (or server pool): See [3]; 135 Pool handle: See [3]; 137 Pool element (PE): See [3]; 139 Pool user (PU): See [3]; 141 Pool element handle: See [3]; 143 ENRP handlespace (or handlespace): See [3]; 145 ENRP client channel: The communication channel through which an ASAP 146 User (either a PE or PU) requests ENRP handlespace service. The 147 client channel is usually defined by the transport address of the 148 home server and a well known port number. The channel MAY make 149 use of multi-cast or a named list of ENRP servers. 151 ENRP server channel: Defined by a well known multicast IP address 152 and a well known port number. All ENRP servers in an operational 153 scope can send multicast messages to other servers through this 154 channel. PEs are also allowed to multicast on this channel 155 occasionally; 157 Home ENRP server: The ENRP server to which a PE or PU currently 158 belongs. A PE MUST only have one home ENRP server at any given 159 time and both the PE and its home ENRP server MUST keep track of 160 this master/slave relationship between them. A PU SHOULD select 161 one of the available ENRP servers as its home ENRP server, but the 162 ENRP server does not need to know, nor does it need to keep track 163 of this relationship. 165 1.2. Conventions 167 The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, 168 SHOULD NOT, RECOMMENDED, NOT RECOMMENDED, MAY, and OPTIONAL, when 169 they appear in this document, are to be interpreted as described in 170 [6]. 172 2. ENRP Message Definitions 174 In this section, we defines the format of all ENRP messages. These 175 are messages sent and received amongst ENRP servers in an operational 176 scope. Messages sent and received between a PE/PU and an ENRP server 177 are part of ASAP and are defined in [1]. A common format, defined in 178 [11], is used for all ENRP and ASAP messages. 180 Most ENRP messages contains a combination of fixed fields and TLV 181 parameters. The TLV parameters are also defined in [11]. 183 All messages, as well as their fields/parameters described below, 184 MUST be transmitted in network byte order (a.k.a. Big Endian, i.e., 185 the most significant byte first). 187 For ENRP, the following message types are defined: 189 Type Message Name 190 ----- ------------------------- 191 0x00 - (reserved by IETF) 192 0x01 - ENRP_PRESENCE 193 0x02 - ENRP_HANDLE_TABLE_REQUEST 194 0x03 - ENRP_HANDLE_TABLE_RESPONSE 195 0x04 - ENRP_HANDLE_UPDATE 196 0x05 - ENRP_LIST_REQUEST 197 0x06 - ENRP_LIST_RESPONSE 198 0x07 - ENRP_INIT_TAKEOVER 199 0x08 - ENRP_INIT_TAKEOVER_ACK 200 0x09 - ENRP_TAKEOVER_SERVER 201 0x0a - ENRP_ERROR 202 0x0b-0xff - (reserved by IETF) 204 2.1. ENRP_PRESENCE message 206 This ENRP message is used to announce (periodically) the presence of 207 an ENRP server, or to probe the status of a peer ENRP sever. 209 0 1 2 3 210 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 1 211 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 212 | Type = 0x01 |0|0|0|0|0|0|0|R| Message Length | 213 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 214 | Sender Server's ID | 215 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 216 | Receiver Server's ID | 217 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 218 : PE Checksum Param : 219 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 220 : Server Information Param (optional) : 221 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 223 R (reply_required) flag: 1 bit 225 Set to '1' if the sender requires a response to this message, 226 otherwise set to '0'. 228 Sender Server's ID: 32 bit (unsigned integer) 230 This is the ID of the ENRP server which sends the message. 232 Receiver Server's ID: 32 bit (unsigned integer) 234 This is the ID of the ENRP server to which the message is 235 intended. If the message is not intended to an individual 236 server (e.g., the message is multicasted to a group of 237 servers), this field MUST be set with all 0's. 239 PE Checksum Parameter: 241 This is a TLV that contains the latest PE checksum of the ENRP 242 server who sends the ENRP_PRESENCE. This parameter SHOULD be 243 included for handlespace consistency auditing. See 244 Section 3.11.1 for details. 246 Server Information Parameter: 248 If present, contains the server information of the sender of 249 this message (Server Information Parameter is defined in [11]). 250 This parameter is optional. However, if this message is sent 251 in response to a received "reply required" ENRP_PRESENCE from a 252 peer, the sender then MUST include its server information. 254 Note, at startup an ENRP server MUST pick a randomly generated, non- 255 zero 32-bit unsigned integer as its ID and MUST use this same ID for 256 its entire life. 258 2.2. ENRP_HANDLE_TABLE_REQUEST message 260 An ENRP server sends this message to one of its peers to request a 261 copy of the handlespace data. This message is normally used during 262 server initialization or handlespace re-synchronization. 264 0 1 2 3 265 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 1 266 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 267 | Type = 0x02 |0|0|0|0|0|0|0|W| Message Length = 0xC | 268 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 269 | Sender Server's ID | 270 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 271 | Receiver Server's ID | 272 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 274 W (oWn-children-only) flag: 1 bit 276 Set to '1' if the sender of this message is only requesting 277 information about the PEs owned by the message receiver. 278 Otherwise, set to '0'. 280 Sender Server's ID: 282 See Section 2.1. 284 Receiver Server's ID: 286 See Section 2.1. 288 2.3. ENRP_HANDLE_TABLE_RESPONSE message 289 0 1 2 3 290 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 1 291 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 292 | Type = 0x03 |0|0|0|0|0|0|M|R| Message Length | 293 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 294 | Sender Server's ID | 295 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 296 | Receiver Server's ID | 297 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 298 : : 299 : Pool entry #1 (see below) : 300 : : 301 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 302 : : 303 : ... : 304 : : 305 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 306 : : 307 : Pool entry #n (see below) : 308 : : 309 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 311 M (More_to_send) flag: 1 bit 313 Set to '1' if the sender has more pool entries to sent in 314 subsequent ENRP_HANDLE_TABLE_RESPONSE messages, otherwise, set 315 to '0'. 317 R (Reject) flag: 1 bit 319 MUST be set to '1' if the sender of this message is rejecting a 320 handlespace request. In such a case, this message MUST be sent 321 with no pool entries included. 323 Message Length: 16 bits (unsigned integer) 325 Indicates the entire length of the message in number of octets. 327 Note, the value in Message Length field will NOT cover any 328 padding at the end of this message. 330 Sender Server's ID: 332 See Section 2.1. 334 Receiver Server's ID: 336 See Section 2.1. 338 Pool entry #1-#n: 340 If R flag is '0', at least one pool entry SHOULD be present in 341 the message. Each pool entry MUST start with a pool handle 342 parameter as defined in section 3.1.7, followed by one or more 343 pool element parameters, i.e.: 345 +---------------------------+ 346 : Pool handle : 347 +---------------------------+ 348 : PE #1 : 349 +---------------------------+ 350 : PE #2 : 351 +---------------------------+ 352 : ... : 353 +---------------------------+ 354 : PE #n : 355 +---------------------------+ 357 2.4. ENRP_HANDLE_UPDATE message 359 0 1 2 3 360 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 1 361 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 362 | Type = 0x04 |0|0|0|0|0|0|0|0| Message Length | 363 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 364 | Sender Server's ID | 365 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 366 | Receiver Server's ID | 367 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 368 | Update Action | (reserved) | 369 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 370 : Pool handle : 371 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 372 : Pool Element : 373 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 375 Message Length: 16 bits (unsigned integer) 377 Indicates the entire length of the message in number of octets. 379 Note, the value in Message Length field will NOT cover any 380 padding at the end of this message. 382 Update Action: 16 bits (unsigned integer) 384 This field indicates what act is requested to the specified PE. 385 It MUST take one of the following values: 387 0x0 - ADD_PE: add or update the specified PE in the ENRP 388 handlespace 390 0x1 - DEL_PE: delete the specified PE from the ENRP 391 handlespace. 393 Other values are reserved by IETF and MUST not be used. 395 Reserved: 16 bits 397 MUST be set to 0's by sender and ignored by the receiver. 399 Sender Server's ID: 401 See Section 2.1. 403 Receiver Server's ID: 405 See Section 2.1. 407 Pool handle: 409 Specifies to which the PE belongs. 411 Pool Element: 413 Specifies the PE. 415 2.5. ENRP_LIST_REQUEST message 417 This ENRP message is used to request a copy of the current known ENRP 418 peer server list. This message is normally sent from a newly started 419 ENRP server to an existing ENRP server as part of the initialization 420 process of the new server. 422 0 1 2 3 423 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 1 424 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 425 | Type = 0x05 |0|0|0|0|0|0|0|0| Message Length = 0xC | 426 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 427 | Sender Server's ID | 428 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 429 | Receiver Server's ID | 430 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 432 Sender Server's ID: 434 See Section 2.1. 436 Receiver Server's ID: 438 See Section 2.1. 440 2.6. ENRP_LIST_RESPONSE message 442 This message is used to respond an ENRP_LIST_REQUEST. 444 0 1 2 3 445 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 1 446 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 447 | Type = 0x06 |0|0|0|0|0|0|0|R| Message Length | 448 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 449 | Sender Server's ID | 450 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 451 | Receiver Server's ID | 452 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 453 : Server Info Param of Peer #1 : 454 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 455 : ... : 456 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 457 : Server Info Param of Peer #n : 458 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 460 R (Reject) flag: 1 bit 462 MUST be set to '1' if the sender of this message is rejecting a 463 peer list request. In such a case, this message MUST be sent 464 with no peer server ID included. 466 Message Length: 16 bits (unsigned integer) 468 Indicates the entire length of the message in number of octets. 470 Note, the value in Message Length field will NOT cover any 471 padding at the end of this message. 473 Sender Server's ID: 475 See Section 2.1. 477 Receiver Server's ID: 479 See Section 2.1. 481 Server Information Parameter of Peer #1-#n: 483 Each contains a Server Information Parameter of a peer known to 484 the sender. The Server Information Parameter is defined in 485 [11]. 487 2.7. ENRP_INIT_TAKEOVER message 489 This message is used by an ENRP server (the takeover initiator) to 490 declare its intention of taking over a specific peer ENRP server. 492 0 1 2 3 493 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 1 494 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 495 | Type = 0x07 |0|0|0|0|0|0|0|0| Message Length | 496 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 497 | Sender Server's ID | 498 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 499 | Receiver Server's ID | 500 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 501 | Target Server's ID | 502 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 504 Sender Server's ID: 506 See Section 2.1. 508 Receiver Server's ID: 510 See Section 2.1. 512 Target Server's ID: 514 Contains the 32-bit server ID of the peer ENRP that is the 515 target of this takeover attempt. 517 2.8. ENRP_INIT_TAKEOVER_ACK message 519 This message is used to acknowledge the takeover initiator that the 520 sender of this message received the ENRP_INIT_TAKEOVER message and 521 that it does not object to the takeover. 523 0 1 2 3 524 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 1 525 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 526 | Type = 0x08 |0|0|0|0|0|0|0|0| Message Length | 527 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 528 | Sender Server's ID | 529 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 530 | Receiver Server's ID | 531 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 532 | Target Server's ID | 533 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 535 Sender Server's ID: 537 See Section 2.1. 539 Receiver Server's ID: 541 See Section 2.1. 543 Target Server's ID: 545 Contains the 32-bit server ID of the peer ENRP that is the 546 target of this takeover attempt. 548 2.9. ENRP_TAKEOVER_SERVER message 550 This message is used by the takeover initiator to declare that a 551 takeover is underway. 553 0 1 2 3 554 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 1 555 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 556 | Type = 0x09 |0|0|0|0|0|0|0|0| Message Length | 557 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 558 | Sender Server's ID | 559 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 560 | Receiver Server's ID | 561 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 562 | Target Server's ID | 563 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 565 Sender Server's ID: 567 See Section 2.1. 569 Receiver Server's ID: 571 See Section 2.1. 573 Target Server's ID: 575 Contains the 32-bit server ID of the peer ENRP that is the 576 target of this takeover operation. 578 2.10. ENRP_ERROR message 580 This message is used by an ENRP server to report an operational error 581 to one of its peers. 583 0 1 2 3 584 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 1 585 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 586 | Type = 0x0a |0|0|0|0|0|0|0|0| Message Length | 587 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 588 | Sender Server's ID | 589 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 590 | Receiver Server's ID | 591 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 592 : Operational Error Parameter : 593 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 594 Sender Server's ID: 596 See Section 2.1. 598 Receiver Server's ID: 600 See Section 2.1. 602 Operational Error Parameter: 604 This parameter, defined in [11], indicates the type of error(s) 605 being reported. 607 3. ENRP Operation Procedures 609 In this section, we discuss the operation procedures defined by ENRP. 610 An ENRP server MUST following these procedures when sending, 611 receiving, or processing ENRP messages. 613 Many of the Rserpool events call for both server-to-server and PU/ 614 PE-to-server message exchanges. Only the message exchanges and 615 activities between an ENRP server and its peer(s) are considered 616 within the ENRP scope and are defined in this document. 618 Procedures for exchanging messages between a PE/PU and ENRP servers 619 are defined in [1]. 621 3.1. Methods for Communicating amongst ENRP Servers 623 Within an Rserpool operational scope, ENRP servers need to 624 communicate with each other in order to exchange information such as 625 the pool membership changes, handlespace data synchronization, etc. 627 Two types of communications are used amongst ENRP servers: 629 o point-to-point message exchange from one ENPR server to a specific 630 peer server, and 632 o announcements from one server to all its peer servers in the 633 operational scope. 635 Point-to-point communication is always carried out over an SCTP 636 association between the sending server and the receiving server. 638 Announcements are communicated out with one of the following two 639 approaches: 641 1. The sending server sends the announcement message to a well-known 642 RSERPOOL IP multicast channel that its peer servers subscribe to. 644 Note: Because IP multicast is not reliable, this approach does 645 not guarantee that all the peers will receive the announcement 646 message. Moreover, since IP multicast is not secure, this 647 approach cannot provide any security to the communication. 649 2. The sending server sends multiple copies of the announcement, one 650 to each of its peer servers, over a set of point-to-point SCTP 651 associations between the sending server and the peers. 653 This approach guarantees the reliable reception of the message. 654 When needed, data security can be achieved by using IP security 655 mechanisms such as IPsec [10] or TLS [9]. 657 In order to maximize inter-operability of ENRP servers, the following 658 rules MUST be followed: 660 1. At the startup time, a new ENRP server SHOULD make a decision on 661 whether it will enable IP multicast for ENRP announcements. This 662 decision should be based on factors such as the availability of 663 IP multicast and the security requirements from the user of 664 Rserpool. 666 2. If an ENRP server disables multicast, it then: 668 A. MUST NOT subscribe to the well-known server multicast 669 channel, i.e., it only receives peer announcements over SCTP 670 associations, and 672 B. MUST transmit all its out-going announcements over point-to- 673 point SCTP associations with its peers. 675 3. If an ENRP server enables itself to use multicast, it then: 677 A. MUST subscribe to the well-known server multicast channel to 678 ready itself for receiving peers' multicast announcements, 680 B. MUST also be prepared to receive peer announcements over 681 point-to-point SCTP associations from peers. 683 C. MUST track internally which peers are multicast-enabled and 684 which are not. Note: A peer is always assumed to be 685 multicast-disabled until/unless an ENRP message of any type 686 is received from that peer over the well-known server 687 multicast channel. 689 D. when sending out an announcement, MUST send a copy to the 690 well-known server multicast channel AND a copy to each of the 691 peers that are marked as multicast-disabled over a point-to- 692 point SCTP association. 694 3.2. ENRP Server Initialization 696 This section describes the steps a new ENRP server needs to take in 697 order to join the other existing ENRP servers, or to initiate the 698 handlespace service if it is the first ENRP server started in the 699 operational scope. 701 3.2.1. Generate a Server Identifier 703 A new ENRP server MUST generate a non-zero, 32-bit server Id that is 704 as unique as possible in the operational scope and this server Id 705 MUST remain unchanged for the lifetime of the server. Normally, a 706 good 32-bit random number will be good enough as the server Id ([13] 707 provides some information on randomness guidelines). 709 Note, there is a very remote chance (about 1 in 4 billion) that two 710 ENRP servers in an operational scope will generate the same server Id 711 and hence cause a server Id conflict in the pool. However, no severe 712 consequence of such a conflict has been identified. 714 3.2.2. Acquire Peer Server List 716 At startup, the ENRP server (initiating server) will first attempt to 717 learn all existing peer ENRP servers in the same operational scope, 718 or to determine that it is along in the scope. 720 The initiating server uses an existing peer server to bootstrap 721 itself into service. We call this peer server the mentor server. 723 3.2.2.1. Find the mentor server 725 If the initiating server is told about an existing peer server 726 through some administrative means (such as DNS query, configuration 727 database, startup scripts, etc), the initiating server SHOULD then 728 use this peer server as its mentor server and SHOULD skip the 729 remaining steps in this subsection. 731 If multiple existing peer servers are specified, the initiating 732 server SHOULD pick one of them as its mentor peer server, keep the 733 others as its backup mentor peers, and skip the remaining steps in 734 this subsection. 736 If no existing peer server is specified to the initiating server AND 737 if multicast is available in the operational scope, the following 738 mentor peer discovery procedures SHOULD be followed: 740 1. The initiating server SHOULD first join the well-known ENRP 741 server multicast channel. 743 2. Then the initiating server SHOULD send an ENRP_PRESENCE message, 744 with the 'Reply_required' flag set, over the multicast channel. 745 Upon the reception of this ENRP_PRESENCE message, a peer server 746 MUST send an ENRP_PRESENCE, without the 'Reply_required' flag, 747 back to the initiating server. 749 3. When the first response to its original ENRP_PRESENCE arrives, 750 the initiating server SHOULD take the sender of this received 751 response as its mentor peer server. This completes the discovery 752 of the mentor peer server. 754 If responses are also received from other peers (a likely event 755 when multiple peers exist in the operational scope at the time 756 the new server started), the initiating server SHOULD keep a list 757 of those responded as its backup mentor peers (see below). 759 4. If no response to its ENRP_PRESENCE message are received after 760 TIMEOUT-SERVER-HUNT seconds, the initiating server SHOULD repeat 761 steps 2) and 3) for up to MAX-NUMBER-SERVER-HUNT times. After 762 that, if there is still no response, the initiating server MUST 763 assume that it is alone in the operational scope. 765 5. If the initiating server determined that it is alone in the 766 scope, it MUST skip the procedures in Section 3.2.2.2 and 767 Section 3.2.3 and MUST consider its initialization completed and 768 start offering ENRP services. 770 Note, if multicast is not available (or not allowed for reasons such 771 as security concerns) in the operational scope, at least one peer 772 server MUST be specified to the initiating server through 773 administrative means, unless the initiation server is the first 774 server to start in the operational scope. 776 Note, if the administratively specified mentor peer(s) fails, the 777 initiating server SHOULD use the auto-discover procedure defined in 778 steps 1-5 above. 780 3.2.2.2. Request complete server list from mentor peer 782 Once the initiating server finds its mentor peer server (by either 783 discovery or administrative means), the initiating server MUST send 784 an ENRP_LIST_REQUEST message to the mentor peer server to request a 785 copy of the complete server list maintained by the mentor peer (see 786 Section 3.9 for maintaining server list). 788 The initiating server SHOULD start a timer every time it finishes 789 sending an ENRP_LIST_REQUEST message. If the timer expires before 790 receiving a response from the mentor peer, the initiating server 791 SHOULD abort and send a new server list request to a backup mentor 792 peer, if one is available. 794 Upon the reception of this request, the mentor peer server SHOULD 795 reply with an ENRP_LIST_RESPONSE message and include in the message 796 body all existing ENRP servers known by the mentor peer. 798 Upon the reception of the ENRP_LIST_RESPONSE message from the mentor 799 peer, the initiating server MUST use the server information carried 800 in the message to initialize its own peer list. 802 However, if the mentor itself is in the process of startup and not 803 ready to provide a peer server list (for example, the mentor peer is 804 waiting for a response to its own ENRP_LIST_REQUEST to another 805 server), it MUST reject the request by the initiating server and 806 respond with an ENRP_LIST_RESPONSE message with the R flag set to 807 '1', and with no server information included in the response. 809 In the case where its ENRP_LIST_REQUEST is rejected by the mentor 810 peer, the initiating server SHOULD either wait for a few seconds and 811 re-send the ENRP_LIST_REQUEST to the mentor server, or if there is a 812 backup mentor peer available, select another mentor peer server and 813 send the ENRP_LIST_REQUEST to the new mentor server. 815 3.2.3. Download ENRP Handlespace Data from Mentor Peer 817 After a peer list download is completed, the initiating server MUST 818 request a copy of the current handlespace data from its mentor peer 819 server, by taking the following steps: 821 1. The initiating server MUST first send a ENRP_HANDLE_TABLE_REQUEST 822 message to the mentor peer, with W flag set to '0', indicating 823 that the entire handlespace is requested. 825 2. Upon the reception of this message, the mentor peer MUST start a 826 download session in which a copy of the current handlespace data 827 maintained by the mentor peer is sent to the initiating server in 828 one or more ENRP_HANDLE_TABLE_RESPONSE messages (Note, the mentor 829 server may find it particularly desirable to use multiple 830 ENRP_HANDLE_TABLE_RESPONSE messages to send the handlespace when 831 the handlespace is large, especially when forming and sending out 832 a single response containing a large handlespace may interrupt 833 its other services). 835 If more than one ENRP_HANDLE_TABLE_RESPONSE message are used 836 during the download, the mentor peer MUST use the M flag in each 837 ENRP_HANDLE_TABLE_RESPONSE message to indicate whether this 838 message is the last one for the download session. In particular, 839 the mentor peer MUST set the M flag to '1' in the outbound 840 ENRP_HANDLE_TABLE_RESPONSE if there is more data to be 841 transferred and MUST keep track of the progress of the current 842 download session. The mentor peer MUST set the M flag to '0' in 843 the last ENRP_HANDLE_TABLE_RESPONSE for the download session and 844 close the download session (i.e., removing any internal record of 845 the session) after sending out the last message. 847 3. During the downloading, every time the initiating server receives 848 an ENRP_HANDLE_TABLE_RESPONSE message, it MUST transfer the data 849 entries carried in the message into its local handlespace 850 database, and then check whether or not this message is the last 851 one for the download session. 853 If the M flag is set to '1' in the just processed 854 ENRP_HANDLE_TABLE_RESPONSE message, the initiating server MUST 855 send another ENRP_HANDLE_TABLE_REQUEST message to the mentor peer 856 to request for the next ENRP_HANDLE_TABLE_RESPONSE message. 858 4. When unpacking the data entries from a ENRP_HANDLE_TABLE_RESPONSE 859 message into its local handlespace database, the initiating 860 server MUST handle each pool entry carried in the message using 861 the following rules: 863 A. If the pool does not exist in the local handlespace, the 864 initiating server MUST creates the pool in the local 865 handlespace and add the PE(s) in the pool entry to the pool. 867 When creating the pool, the initiation server MUST set the 868 overall member selection policy type of the pool to the 869 policy type indicated in the first PE. 871 B. If the pool already exists in the local handlespace, but the 872 PE(s) in the pool entry is not currently a member of the 873 pool, the initiating server MUST add the PE(s) to the pool. 875 C. If the pool already exists in the local handlespace AND the 876 PE(s) in the Pool entry is already a member of the pool, the 877 initiating server SHOULD replace the attributes of the 878 existing PE(s) with the new information. 880 5. When the last ENRP_HANDLE_TABLE_RESPONSE message is received from 881 the mentor peer and unpacked into the local handlespace, the 882 initialization process is completed and the initiating server 883 SHOULD start to provide ENRP services. 885 Under certain circumstances, the mentor peer itself may not be able 886 to provide a handlespace download to the initiating server. For 887 example, the mentor peer is in the middle of initializing its own 888 handlespace database, or it has currently too many download sessions 889 open to other servers. 891 In such a case, the mentor peer MUST reject the request by the 892 initiating server and respond with an ENRP_HANDLE_TABLE_RESPONSE 893 message with the R flag set to '1', and with no pool entries included 894 in the response. 896 In the case where its ENRP_HANDLE_TABLE_REQUEST is rejected by the 897 mentor peer, the initiating server SHOULD either wait for a few 898 seconds and re-send the ENRP_HANDLE_TABLE_REQUEST to the mentor 899 server, or if there is a backup mentor peer available, select another 900 mentor peer server and send the ENRP_HANDLE_TABLE_REQUEST to the new 901 mentor server. 903 A started handlespace download session may get interrupted for some 904 reason. To cope with this, the initiating server SHOULD start a 905 timer every time it finishes sending an ENRP_HANDLE_TABLE_REQUEST to 906 its mentor peer. If this timer expires without receiving a response 907 from the mentor peer, the initiating server SHOULD abort the current 908 download session and re-start a new handlespace download with a 909 backup mentor peer, if one is available. 911 Similarly, after sending out an ENRP_HANDLE_TABLE_RESPONSE, if the 912 mentor peer has still more data to send, it SHOULD start a session 913 timer. If this timer expires without receiving another request from 914 the initiating server, the mentor peer SHOULD abort the session, 915 cleaning out any resource and record of the session. 917 3.3. Handle PE Registration 919 To register itself with the handlespace, a PE sends an 920 ASAP_REGISTRATION message to its home ENRP server. The format of 921 ASAP_REGISTRATION message and rules of sending it are defined in [1]. 923 In the ASAP_REGISTRATION message, the PE indicates the handle of the 924 pool it wishes to join in a pool handle parameter, and its complete 925 transport information and any load control information in a PE 926 parameter. 928 The ENRP server handles the ASAP_REGISTRATION message according to 929 the following rules: 931 1. If the named pool does not exist in the handlespace, the ENRP 932 server MUST creates a new pool with that handle in the 933 handlespace and add the PE to the pool as its first PE; 935 When a new pool is created, the overall member selection policy 936 of the pool MUST be set to the policy type indicated by the first 937 PE, the overall pool transport type MUST be set to the transport 938 type indicated by the PE, and the overall pool data/control 939 channel configuration MUST be set to what is indicated in the 940 Transport Use field of the User Transport parameter by the 941 registering PE. 943 2. If the named pool already exists in the handlespace, but the 944 requesting PE is not currently a member of the pool, the ENRP 945 server will add the PE as a new member to the pool; 947 However, before adding the PE to the pool, the server MUST check 948 if the policy type, transport type, and transport usage indicated 949 by the registering PE is consistent with those of the pool. If 950 different, the ENRP server MUST reject the registration. 952 3. If the named pool already exists in the handlespace AND the 953 requesting PE is already a member of the pool, the ENRP server 954 SHOULD consider this as a re-registration case. The ENRP server 955 MUST perform the same tests on policy, transport type, transport 956 use, as described above. If the re-registration is accepted 957 after the test, the ENRP Server SHOULD replace the attributes of 958 the existing PE with the information carried in the received 959 ASAP_REGISTRATION message. 961 4. After accepting the registration, the ENRP server MUST assign 962 itself the owner of this PE. If this is a re-registration, the 963 ENRP server MUST take over ownership of this PE regardless of 964 whether the PE was previously owned by this server or by another 965 server. The ENRP server MUST also record the SCTP transport 966 address from which it received the ASAP_REGISTRATION in the ASAP 967 Transport parameter TLV inside the PE parameter of this PE. 969 5. The ENRP server may reject the registration due to other reasons 970 such as invalid values, lack of resource, authentication failure, 971 etc. 973 In all above cases, the ENRP server MUST reply to the requesting PE 974 with an ASAP_REGISTRATION_RESPONSE message. If the registration is 975 accepted, the ENRP server MUST set the 'R' flag in the 976 ASAP_REGISTRATION_RESPONSE to '0'. If the registration is rejected, 977 the ENRP server MUST indicate the rejection by setting the 'R' flag 978 in the ASAP_REGISTRATION_RESPONSE to '1'. 980 If the registration is rejected, the ENRP server SHOULD include the 981 proper error cause(s) in the ASAP_REGISTRATION_RESPONSE message. 983 If the registration is granted (either a new registration or a re- 984 registration case), the ENRP server MUST assign itself to be the home 985 ENRP server of the PE, i.e., to "own" the PE. 987 Implementation note: for better performance, the ENRP server may 988 find it both efficient and convenient to internally maintain two 989 separate PE lists or tables - one is for the PEs that are "owned" 990 by the ENRP server and the other for all the PEs owned by its 991 peer(s). 993 Moreover, if the registration is granted, the ENRP server MUST take 994 the handlespace update action as described in Section 3.6 to inform 995 its peers about the change just made. If the registration is denied, 996 no message will be sent to its peers. 998 3.3.1. Rules on PE Re-registration 1000 A PE may re-register itself to the handlespace with a new set of 1001 attributes in order to, for example, extend its registration life, 1002 change its load factor value, etc. 1004 A PE may modify its load factor value at any time via re- 1005 registration. Based on the number of PEs in the pool and the pool's 1006 overall policy type, this operation allows the PE to dynamically 1007 control its share of inbound messages received by the pool (also see 1008 Section ???? in [1] for more on load control). 1010 Moreover, when re-registering, the PE MUST NOT change its policy 1011 type. The server MUST reject the re-registration if the PE attempt 1012 to change its policy type. In the rejection, the server SHOULD 1013 attach an error code "Pooling Policy Inconsistent". 1015 Regardless whether it is the current owner of the PE, if the re- 1016 registration is granted to the PE, the ENRP server MUST assign itself 1017 to be the new home ENRP server of the PE. 1019 Moreover, if the re-registration is granted, the ENRP server MUST 1020 take the handlespace update action as described in Section 3.6 to 1021 inform its peers about the change just made. If the re-registration 1022 is denied, no message will be sent to its peers. 1024 3.4. Handle PE De-registration 1026 To remove itself from a pool, a PE sends an ASAP_DEREGISTRATION 1027 message to its home ENRP server. The complete format of 1028 ASAP_DEREGISTRATION message and rules of sending it are defined in 1029 [1]. 1031 In the ASAP_DEREGISTRATION message the PE indicates the handle of the 1032 pool it belongs to in a pool handle parameter and provides its PE 1033 identifier. 1035 Upon receiving the message, the ENRP server SHALL remove the PE from 1036 its handlespace. Moreover, if the PE is the last one of the named 1037 pool, the ENRP server will remove the pool from the handlespace as 1038 well. 1040 If the ENRP server fails to find any record of the PE in its 1041 handlespace, it SHOULD consider the de-registration granted and 1042 completed, and send an ASAP_DEREGISTRATION_RESPONSE message to the 1043 PE. 1045 The ENRP server may reject the de-registration request for various 1046 reasons, such as invalid parameters, authentication failure, etc. 1048 In response, the ENRP server MUST send an 1049 ASAP_DEREGISTRATION_RESPONSE message to the PE. If the de- 1050 registration is rejected, the ENRP server MUST indicate the rejection 1051 by including the proper Operational Error parameter. 1053 It should be noted that de-registration does not stop the PE from 1054 sending or receiving application messages. 1056 Once the de-registration request is granted AND the PE removed from 1057 its local copy of the handlespace, the ENRP server MUST take the 1058 handlespace update action described in Section 3.6 to inform its 1059 peers about the change just made. Otherwise, NO message SHALL be 1060 send to its peers. 1062 3.5. Pool Handle Translation 1064 A PU uses the pool handle translation service of an ENRP server to 1065 resolve a pool handle to a list of accessible transport addresses of 1066 the member PEs of the pool. 1068 This requires the PU to send an ASAP_HANDLE_RESOLUTION message to its 1069 home ENRP server and in the ASAP_HANDLE_RESOLUTION message specify 1070 the pool handle to be translated in a Pool Handle parameter. 1071 Complete definition of the ASAP_HANDLE_RESOLUTION message and the 1072 rules of sending it are defined in [1]. 1074 An ENRP server SHOULD be prepared to receive ASAP_HANDLE_RESOLUTION 1075 requests from PUs either over an SCTP association on the well-know 1076 SCTP port, or over a TCP connection on the well-know TCP port. 1078 Upon reception of the ASAP_HANDLE_RESOLUTION message, the ENRP server 1079 MUST first look up the pool handle in its handlespace. If the pool 1080 exits, the home ENRP server MUST compose and send back an 1081 ASAP_HANDLE_RESOLUTION_RESPONSE message to the requesting PU. 1083 In the response message, the ENRP server SHOULD list all the PEs 1084 currently registered in this pool, in a list of PE parameters. The 1085 ENRP server MUST also include a pool member selection policy 1086 parameter to indicate the overall member selection policy for the 1087 pool, if the current pool member selection policy is not round-robin 1088 (if the overall policy is round-Robin, this parameter MAY be 1089 omitted?). 1091 If the named pool does not exist in the handlespace, the ENRP server 1092 MUST reject the handle resolution request by responding with an 1093 ASAP_HANDLE_RESOLUTION_RESPONSE message carrying a Unknown Poor 1094 Handle error. 1096 The complete format of ASAP_HANDLE_RESOLUTION_RESPONSE message and 1097 the rules of receiving it are defined in [1]. 1099 3.6. Server Handlespace Update 1101 This includes a set of update operations used by an ENRP server to 1102 inform its peers when its local handlespace is modified, e.g., 1103 addition of a new PE, removal of an existing PE, change of pool or PE 1104 properties. 1106 3.6.1. Announcing Addition or Update of PE 1108 When a new PE is granted registration to the handlespace or an 1109 existing PE is granted a re-registration, the home ENRP server uses 1110 this procedure to inform all its peers. 1112 This is an ENRP announcement and is sent to all the peer of the home 1113 ENRP server. See Section 3.1 on how announcements are sent. 1115 An ENRP server MUST announce this update to all its peers in a 1116 ENRP_HANDLE_UPDATE message with the Update Action field set to 1117 ADD_PE, indicating the addition of a new PE or the modification of an 1118 existing PE. The complete new information of the PE and the pool its 1119 belongs to MUST be indicated in the message with a PE parameter and a 1120 Pool Handle parameter, respectively. 1122 The home ENRP server SHOULD fill in its server Id in the Sender 1123 Server's ID field and leave the Receiver Server's ID blank (i.e., all 1124 0's). 1126 When a peer receives this ENRP_HANDLE_UPDATE message, it MUST take 1127 the following actions: 1129 1. If the named pool indicated by the pool handle does not exist in 1130 its local copy of the handlespace, the peer MUST create the named 1131 pool in its local handlespace and add the PE to the pool as the 1132 first PE. It MUST then copy in all other attributes of the PE 1133 carried in the message. 1135 When the new pool is created, the overall member selection policy 1136 of the pool MUST be set to the policy type indicated by the PE. 1138 2. If the named pool already exists in the peer's local copy of the 1139 handlespace AND the PE does not exist, the peer MUST add the PE 1140 to the pool as a new PE and copy in all attributes of the PE 1141 carried in the message. 1143 3. If the named pool exists AND the PE is already a member of the 1144 pool, the peer MUST replace the attributes of the PE with the new 1145 information carried in the message. 1147 3.6.2. Announcing Removal of PE 1149 When an existing PE is granted de-registration or is removed from its 1150 handlespace for some other reasons (e.g., purging an unreachable PE, 1151 see Section 3.7), the ENRP server MUST uses this procedure to inform 1152 all its peers about the change just made. 1154 This is an ENRP announcement and is sent to all the peer of the home 1155 ENRP server. See Section 3.1 on how announcements are sent. 1157 An ENRP server MUST announce the PE removal to all its peers in an 1158 ENRP_HANDLE_UPDATE message with the Update Action field set to 1159 DEL_PE, indicating the removal of an existing PE. The complete 1160 information of the PE and the pool its belongs to MUST be indicated 1161 in the message with a PE parameter and a Pool Handle parameter, 1162 respectively. 1164 [editor's note: only the pool handle and the PE's id are needed, it 1165 should reduce the size of the message] 1167 The sending server MUST fill in its server ID in the Sender Server's 1168 ID field and leave the Receiver Server's ID blank (i.e., set to all 1169 0's). 1171 When a peer receives this ENRP_HANDLE_UPDATE message, it MUST first 1172 find pool and the PE in its own handlespace, and then remove the PE 1173 from its local handlespace. If the removed PE is the last one in the 1174 pool, the peer MUST also delete the pool from its local handlespace. 1176 If the peer fails to find the PE or the pool in its handlespace, it 1177 SHOULD take no further actions. 1179 3.7. Detecting and Removing Unreachable PE 1181 Whenever a PU finds a PE unreachable (e.g., via an SCTP SEND.FAILURE 1182 Notification, see section 10.2 of [8]), the PU SHOULD send an 1183 ASAP_ENDPOINT_UNREACHABLE message to its home ENRP server. The 1184 message SHOULD contain the pool handle and the PE Id of the 1185 unreachable PE. 1187 Upon the reception of an ASAP_ENDPOINT_UNREACHABLE message, a server 1188 MUST immediately send a point-to-point ASAP_ENDPOINT_KEEP_ALIVE 1189 message to the PE in question (the 'H' flag in the message SHOULD be 1190 set to '0' in this case). If this ASAP_ENDPOINT_KEEP_ALIVE fails 1191 (e.g., it results in an SCTP SEND.FAILURE notification), the ENRP 1192 server MUST consider the PE as truly unreachable and MUST remove the 1193 PE from its handlespace and take actions described in Section 3.6.2. 1195 If the ASAP_ENDPOINT_KEEP_ALIVE message is transmitted successfully 1196 to the PE, the ENRP server MUST retain the PE in its handlespace. 1197 Moreover, the server SHOULD keep a counter to record how many 1198 ASAP_ENDPOINT_UNREACHABLE messages it has received reporting 1199 reachability problem relating to this PE. If the counter exceeds the 1200 protocol threshold MAX-BAD-PE-REPORT, the ENRP server SHOULD remove 1201 the PE from its handlespace and take actions described in 1202 Section 3.6.2. 1204 Optionally, an ENRP server may also periodically send point-to-point 1205 ASAP_ENDPOINT_KEEP_ALIVE (with 'H' flag set to '0') messages to each 1206 of the PEs owned by the ENRP server in order to check their 1207 reachability status. If the send of ASAP_ENDPOINT_KEEP_ALIVE to a PE 1208 fails, the ENRP server MUST consider the PE as unreachable and MUST 1209 remove the PE from its handlespace and take actions described in 1210 Section 3.6.2. Note, if an ENRP server owns a large number of PEs, 1211 the implementation should pay attention not to flood the network with 1212 bursts of ASAP_ENDPOINT_KEEP_ALIVE messages. Instead, the 1213 implementation should try to smooth out the ASAP_ENDPOINT_KEEP_ALIVE 1214 message traffic over time. 1216 The complete definition and rules of sending 1217 ASAP_ENDPOINT_UNREACHABLE and receiving ASAP_ENDPOINT_KEEP_ALIVE 1218 messages are described in [1]. 1220 3.8. Helping PE and PU to Discover Home ENRP Server 1222 At its startup time, or whenever its current home ENRP server is not 1223 providing services, a PE or PU will attempt to find a new home 1224 server. For this reason, the PE or PU will need to maintain a list 1225 of currently available ENRP servers in its scope. 1227 To help the PE or PU maintaining this list, an ENRP server, if it is 1228 enabled for multicast, SHOULD periodically send out an 1229 ASAP_SERVER_ANNOUNCE message every SERVER-ANNOUNCE-CYCLE seconds to 1230 the well-known ASAP multicast channel. And in the 1231 ASAP_SERVER_ANNOUNCE message the ENRP server SHOULD include all the 1232 transport addresses available for ASAP communications. If the ENRP 1233 server only supports SCTP for ASAP communications, the transport 1234 information MAY be omitted in the ASAP_SERVER_ANNOUNCE message. 1236 For the complete procedure of this, see Section 3.6?? in [1]. 1238 3.9. Maintaining Peer List and Monitoring Peer Status 1240 An ENRP server MUST keep an internal record on the status of each of 1241 its known peers. This record is referred to as the server's "peer 1242 list" 1244 3.9.1. Discovering New Peer 1246 If a message of any type is received from a previously unknown peer, 1247 the ENRP server MUST consider this peer a new peer in the operational 1248 scope and add it to the peer list. 1250 The ENRP server MUST send an ENRP_PRESENCE message with the Reply- 1251 required flag set to '1' to the source address found in the arrived 1252 message. This will force the new peer to reply with its own 1253 ENRP_PRESENCE containing its full server information (see 1254 Section 2.1). 1256 [editor's note: should we ask for a peer list from the new peer? this 1257 may help mending two split networks.] 1259 3.9.2. Server Sending Heartbeat 1261 Every PEER-HEARTBEAT-CYCLE seconds, an ENRP server MUST announce its 1262 continued presence to all its peer with a ENRP_PRESENCE message. In 1263 the ENRP_PRESENCE message, the ENRP server MUST set the 1264 'Replay_required' flag to '0', indicating that no response is 1265 required. 1267 The arrival of this periodic ENRP_PRESENCE message will cause all its 1268 peers to update their internal variable "peer.last.heard" for the 1269 sending server (see Section 3.9.3 for more details). 1271 3.9.3. Detecting Peer Server Failure 1273 An ENRP server MUST keep an internal variable "peer.last.heard" for 1274 each of its known peers and the value of this variable MUST be 1275 updated to the current local time every time a message of any type 1276 (point-to-point or announcement) is received from the corresponding 1277 peer. 1279 If a peer has not been heard for more than MAX-TIME-LAST-HEARD 1280 seconds, the ENRP server MUST immediately send a point-to-point 1281 ENRP_PRESENCE with 'Reply_request' flag set to '1' to that peer. 1283 If the send fails or the peer does not reply after MAX-TIME-NO- 1284 RESPONSE seconds, the ENRP server MUST consider the peer server dead 1285 and SHOULD initiate the takeover procedure defined in Section 3.10. 1287 3.10. Taking-over a Failed Peer Server 1289 In the following descriptions, We call the ENRP server that detects 1290 the failed peer server and initiates the take-over the "initiating 1291 server" and the failed peer server the "target server." 1293 3.10.1. Initiate Server Take-over Arbitration 1295 The initiating server SHOULD first start a take-over arbitration 1296 process by announcing an ENRP_INIT_TAKEOVER message to all its peer 1297 servers. See Section 3.1 on how announcements are sent. In the 1298 message, the initiating server MUST fill in the Sender Server's ID 1299 and Target Server's ID. 1301 After announcing the ENRP_INIT_TAKEOVER message, the initiating 1302 server SHOULD wait for an ENRP_INIT_TAKEOVER_ACK message from _each_ 1303 of its known peers, except of the target server. [editor's note: how 1304 long should it wait?] 1306 Each of the peer servers that receives the ENRP_INIT_TAKEOVER message 1307 from the initiating server SHOULD take the following actions: 1309 1. If the peer server finds that itself is the target server 1310 indicated in the ENRP_INIT_TAKEOVER message, it MUST immediately 1311 announce an ENRP_PRESENCE message to all its peer ENRP servers in 1312 an attempt to stop this take-over process. This indicates a 1313 false failure detection case by the initiating server. 1315 2. If the peer server finds that itself has already started its own 1316 take-over arbitration process on the same target server, it MUST 1317 perform the following arbitration: 1319 A. if the peer's server ID is smaller in value than the Sender 1320 Server's ID in the arrived ENRP_INIT_TAKEOVER message, the 1321 peer server SHOULD immediately abort its own take-over 1322 attempt. Moreover, the peer SHOULD mark the target server as 1323 "not active" on its internal peer list so that its status 1324 will no longer be monitored by the peer, and reply the 1325 initiating server with an ENRP_INIT_TAKEOVER_ACK message. 1327 B. Otherwise, the peer MUST ignore the ENRP_INIT_TAKEOVER 1328 message and take no action. 1330 3. If the peer finds that it is neither the target server nor is in 1331 its own take-over process, the peer SHOULD: a) mark the target 1332 server as "not active" on its internal peer list so that its 1333 status will no longer be monitored by this peer, and b) reply to 1334 the initiating server with an ENRP_INIT_TAKEOVER_ACK message. 1336 Once the initiating server has received ENRP_INIT_TAKEOVER_ACK 1337 message from _all_ of its currently known peers (except for the 1338 target server), it SHOULD consider that it has won the arbitration 1339 and SHOULD proceed to complete the take-over, following the steps 1340 described in Section 3.10.2. 1342 However, if it receives an ENRP_PRESENCE from the target server at 1343 any point in the arbitration process, the initiating server SHOULD 1344 immediately abort the take-over process and mark the status of the 1345 target server as "active". 1347 3.10.2. Take-over Target Peer Server 1349 The initiating ENRP server SHOULD first send, via an announcement, a 1350 ENRP_TAKEOVER_SERVER message to inform all its active peers that the 1351 take-over is enforced. The target server's ID MUST be filled in the 1352 message. The initiating server SHOULD then remove the target server 1353 from its internal peer list. 1355 Then it SHOULD examine its local copy of the handlespace and claim 1356 ownership of each of the PEs originally owned by the target server, 1357 by following these steps: 1359 1. mark itself as the home ENRP server of each of the PEs originally 1360 owned by the target server; 1362 2. send a point-to-point ASAP_ENDPOINT_KEEP_ALIVE message, with the 1363 'H' flag set to '1', to each of the PEs. This will trigger the 1364 PE to adopt the initiating sever as its new home ENRP server; 1366 When a peer receives the ENRP_TAKEOVER_SERVER message from the 1367 initiating server, it SHOULD update its local peer list and PE cache 1368 by following these steps: 1370 1. remove the target server from its internal peer list; 1372 2. update the home ENRP server of each PE in its local copy of the 1373 handlespace to be the sender of the message, i.e., the initiating 1374 server. 1376 3.11. Handlespace Data Auditing and Re-synchronization 1378 Message losses or certain temporary breaks in network connectivity 1379 may result in data inconsistency in the local handlespace copy of 1380 some of the ENRP servers in an operational scope. Therefore, each 1381 ENRP server in the operational scope SHOULD periodically verify that 1382 its local copy of handlespace data is still in sync with that of its 1383 peers. 1385 This section defines the auditing and re-synchronization procedures 1386 for an ENRP server to maintain its handlespace data consistency. 1388 3.11.1. Auditing Procedures 1390 The auditing of handlespace consistency is based on the following 1391 procedures: 1393 1. An ENRP server SHOULD keep a separate PE checksum (a 32-bit 1394 integer internal variable) for each of its known peers and for 1395 itself. For an ENRP server with 'k' known peers, we denote these 1396 internal variables as "pe.checksum.pr0", "pe.checksum.pr1", ..., 1397 "pe.checksum.prk", where "pe.checksum.pr0" is the server's own PE 1398 checksum. The definition and detailed algorithm for calculating 1399 these PE checksum variables are given in Section 3.11.2. 1401 2. Each time an ENRP server sends out an ENRP_PRESENCE, it SHOULD 1402 include in the message its current PE checksum (i.e., 1403 "pe.checksum.pr0"). 1405 3. When an ENRP server (server A) receives a PE checksum (carried in 1406 an arrived ENRP_PRESENCE) from a peer ENRP server (server B), 1407 server A SHOULD compare the PE checksum found in the 1408 ENRP_PRESENCE with its own internal PE checksum of server B 1409 (i.e., "pe.checksum.prB"). 1411 4. If the two values match, server A will consider that there is no 1412 handlespace inconsistency between itself and server B and should 1413 take no further actions. 1415 5. If the two values do NOT match, server A SHOULD consider that 1416 there is a handlespace inconsistency between itself and server B 1417 and a re-synchronization process SHOULD be carried out 1418 immediately with server B (see Section 3.11.3). 1420 3.11.2. PE Checksum Calculation Algorithm 1422 When an ENRP server (server A) calculate an internal PE checksum for 1423 a peer (server B), it MUST use the following algorithm. 1425 Let us assume that in server A's internal handlespace there are 1426 currently 'M' PEs that are owned by server B. Each of the 'M' PEs 1427 will then contribute to the checksum calculation with the following 1428 byte block: 1430 0 1 2 3 1431 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 1432 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1433 : Pool handle string of the pool the PE belongs (padded with : 1434 : zeros to next 32-bit word boundary if needed) : 1435 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1436 | PE Id (4 octets) | 1437 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1439 Note, these are not TLVs. This byte block gives each PE a unique 1440 byte pattern in the scope. The 16-bit PE checksum for server B 1441 "pe.checksum.prB" is then calculated over the byte blocks contributed 1442 by the 'M' PEs one by one. The PE checksum calculation MUST use the 1443 Internet algorithm described in [4]. 1445 Server A MUST calculate its own PE checksum (i.e., "pe.checksum.pr0") 1446 in the same fashion, using the byte blocks of all the PEs owned by 1447 itself. 1449 Note, whenever an ENRP finds that its internal handlespace has 1450 changed (e.g., due to PE registration/deregistration, receiving peer 1451 updates, removing failed PEs, downloading handlespace pieces from a 1452 peer, etc.), it MUST immediately update all its internal PE checksums 1453 that are affected by the change. 1455 Implementation Note: when the internal handlespace changes (e.g., a 1456 new PE added or an existing PE removed), an implementation needs not 1457 to re-calculate the affected PE checksum; it should instead simply 1458 update the checksum by adding or subtracting the byte block of the 1459 corresponding PE from the previous checksum value. 1461 3.11.3. Re-synchronization Procedures 1463 Once an ENRP server determines that there is inconsistency between 1464 its local handlespace data and a peer's handlespace data with 1465 regarding to the PEs owned by that peer, it SHOULD perform the 1466 following steps to re-synchronize the data: 1468 1. The ENRP server SHOULD first "mark" every PE it knows about that 1469 is owned by the peer in its local handlespace database; 1471 2. The ENRP server SHOULD then send an ENRP_HANDLE_TABLE_REQUEST 1472 message with W flag set to '1' to the peer to request a complete 1473 list of PEs owned by the peer; 1475 3. Upon reception of the ENRP_HANDLE_TABLE_REQUEST message with W 1476 flag set to '1', the peer server SHOULD immediately respond with 1477 an ENRP_HANDLE_TABLE_RESPONSE message listing all PEs currently 1478 owned by the peer. 1480 4. Upon reception of the ENRP_HANDLE_TABLE_RESPONSE message, the 1481 ENRP server SHOULD transfer the PE entries carried in the message 1482 into its local handlespace database. If an PE entry being 1483 transferred already exists in its local database, the ENRP server 1484 MUST replace the entry with the copy found in the message and 1485 remove the "mark" from the entry. 1487 5. After transferring all the PE entries from the received 1488 ENRP_HANDLE_TABLE_RESPONSE message into its local database, the 1489 ENRP server SHOULD check whether there are still PE entries that 1490 remain "marked" in its local handlespace. If so, the ENRP server 1491 SHOULD silently remove those "marked" entries. 1493 Note, similar to what is described in Section 3.2.3, the peer may 1494 reject the ENRP_HANDLE_TABLE_REQUEST or use more than one 1495 ENRP_HANDLE_TABLE_RESPONSE message to respond. 1497 3.12. Handling Unrecognized Message or Unrecognized Parameter 1499 When an ENRP server receives an ENRP message with an unknown message 1500 type or a message of known type that contains an unknown parameter, 1501 it SHOULD handle the unknown message or the unknown parameter 1502 according to the unrecognized message and parameter handling rules 1503 defined in Sections 3 and 4 in [11]. 1505 According to the rules, if an error report to the message sender is 1506 needed, the ENRP server that discovered the error SHOULD send back an 1507 ENRP_ERROR message with proper error cause code. 1509 4. Variables and Thresholds 1511 4.1. Variables 1513 peer.last.heard - the local time that a peer server was last heard 1514 (via receiving either a multicast or point-to-point message from 1515 the peer). 1517 pe.checksum.pr - the internal 32-bit PE checksum that an ENRP server 1518 keeps for a peer. A separate PE checksum is kept for each of its 1519 known peers as well as for itself. 1521 4.2. Thresholds 1523 MAX-NUMBER-SERVER-HUNT - the maximal number of attempts a sender 1524 will make to contact an ENRP server (Default=3 times). 1526 TIMEOUT-SERVER-HUNT - pre-set threshold for how long a sender will 1527 wait for a response from an ENRP server (Default=5 seconds). 1529 PEER-HEARTBEAT-CYCLE - the period for an ENRP server to announce a 1530 heartbeat message to all its known peers. (Default=30 secs.) 1532 SERVER-ANNOUNCE-CYCLE - the period for an ENRP server to announce a 1533 SERVER_ANNOUNCE message to all PEs and PUs. (Default=5 secs.) 1535 MAX-TIME-LAST-HEARD - pre-set threshold for how long an ENRP server 1536 will wait before considering a silent peer server potentially 1537 dead. (Default=61 secs.) 1539 MAX-TIME-NO-RESPONSE - pre-set threshold for how long a message 1540 sender will wait for a response after sending out a message. 1541 (Default=5 secs.) 1543 MAX-BAD-PE-REPORT - the maximal number of unreachability reports on 1544 a PE that an ENRP server will allow before purging this PE from 1545 the handlespace. (Default=3) 1547 5. Security Considerations 1549 Threats Introduced by Rserpool and Requirements for Security in 1550 Response to Threats [12] describes the threats to the Rserpool 1551 architecture in detail and lists the security requirements in 1552 response to each threat. From the threats described in this 1553 document, the security services required for the Rserpool protocol 1554 are enumerated below. 1556 Threat 1) PE registration/deregistration flooding or spoofing 1557 ----------- 1558 Security mechanism in response: ENRP server authenticates the PE 1560 Threat 2) PE registers with a malicious ENRP server 1561 ----------- 1562 Security mechanism in response: PE authenticates the ENRP server 1564 Threat 1 and 2 taken together results in mutual authentication of the 1565 ENRP server and the PE. 1567 Threat 3) Malicious ENRP server joins the ENRP server pool 1568 ----------- 1569 Security mechanism in response: ENRP servers mutually authenticate 1571 Threat 4) A PU communicates with a malicious ENRP server for handle 1572 resolution 1573 ----------- 1574 Security mechanism in response: The PU authenticates the ENRP server 1576 Threat 5) Replay attack 1577 ----------- 1578 Security mechanism in response: Security protocol which has 1579 protection from replay attacks 1581 Threat 6) Corrupted data which causes a PU to have misinformation 1582 concerning a pool handle resolution 1583 ----------- 1584 Security mechanism in response: Security protocol which supports 1585 integrity protection 1587 Threat 7) Eavesdropper snooping on handlespace information 1588 ----------- 1589 Security mechanism in response: Security protocol which supports data 1590 confidentiality 1592 Threat 8) Flood of ASAP_ENDPOINT_UNREACHABLE messages from the PU to 1593 ENRP server 1594 ----------- 1595 Security mechanism in response: ASAP must control the number of 1596 endpoint unreachable messages transmitted from the PU to the ENRP 1597 server. 1599 Threat 9) Flood of Endpoint_KeepAlive messages to the PE from the 1600 ENRP server 1601 ----------- 1602 Security mechanism in response: ENRP server must control the number 1603 of Endpoint_KeepAlive messages to the PE 1605 To summarize the threats 1-7 require security mechanisms which 1606 support authentication, integrity, data confidentiality, protection 1607 from replay attacks. 1609 For Rserpool we need to authenticate the following: 1611 PU <---- ENRP Server (PU authenticates the ENRP server) 1612 PE <----> ENRP Server (mutual authentication) 1613 ENRP server <-----> ENRP Server (mutual authentication) 1615 We do not define any new security mechanisms specifically for 1616 responding to threats 1-7. Rather we use existing IETF security 1617 protocols to provide the security services required. TLS supports 1618 all these requirements and MUST be implemented. The 1619 TLS_RSA_WITH_AES_128_CBC_SHA ciphersuite MUST be supported at a 1620 minimum by implementers of TLS for Rserpool. For purposes of 1621 backwards compatibility, ENRP SHOULD support 1622 TLS_RSA_WITH_3DES_EDE_CBC_SHA. Implementers MAY also support any 1623 other ciphersuite. 1625 Threat 8 requires the ASAP protocol to limit the number of 1626 ASAP_ENDPOINT_UNREACHABLE messages (see Section 3.5??? in [1]) to the 1627 ENRP server. 1629 Threat 9 requires the ENRP protocol to limit the number of 1630 Endpoint_KeepAlive messages to the PE (see Section x.y???). 1632 5.1. Implementing Security Mechanisms 1634 ENRP servers, PEs, PUs MUST implement TLS. ENRP servers and PEs must 1635 support mutual authentication. ENRP servers must support mutual 1636 authentication among themselves. PUs MUST authenticate ENRP servers. 1638 ENRP servers and PEs SHOULD possess a site certificate whose subject 1639 corresponds to their canonical hostname. PUs MAY have certificates 1640 of their own for mutual authentication with TLS, but no provisions 1641 are set forth in this document for their use. All Rserpool elements 1642 that support TLS MUST have a mechanism for validating certificates 1643 received during TLS negotiation; this entails possession of one or 1644 more root certificates issued by certificate authorities (preferably 1645 well-known distributors of site certificates comparable to those that 1646 issue root certificates for web browsers). 1648 Implementations MUST support TLS with SCTP as described in RFC3436 1649 [9] or TLS over TCP as described in RFC2246 [7]. When using TLS/SCTP 1650 we must ensure that RSerPool does not use any features of SCTP that 1651 are not available to an TLS/SCTP user. This is not a difficult 1652 technical problem, but simply a requirement. When describing an API 1653 of the RSerPool lower layer we have also to take into account the 1654 differences between TLS and SCTP. 1656 6. Acknowledgements 1658 The authors wish to thank John Loughney, Lyndon Ong, Walter Johnson, 1659 Thomas Dreibholz, and many others for their invaluable comments and 1660 feedback. 1662 7. References 1664 7.1. Normative References 1666 [1] Stewart, R., Xie, Q., Stillman, M., and M. Tuexen, "Aggregate 1667 Server Access Protocol (ASAP)", draft-ietf-rserpool-asap-12 1668 (work in progress), July 2005. 1670 [2] Tuexen, M., Xie, Q., Stewart, R., Shore, M., Ong, L., Loughney, 1671 J., and M. Stillman, "Requirements for Reliable Server 1672 Pooling", RFC 3237, January 2002. 1674 [3] Tuexen, M., Xie, Q., Stewart, R., Shore, M., Loughney, J., and 1675 A. Silverton, "Architecture for Reliable Server Pooling", 1676 draft-ietf-rserpool-arch-10 (work in progress), July 2005. 1678 [4] Braden, R., Borman, D., and C. Partridge, "Computing the 1679 Internet Checksum", RFC 1071, September 1988. 1681 [5] Bradner, S., "The Internet Standards Process -- Revision 3", 1682 BCP 9, RFC 2026, October 1996. 1684 [6] Bradner, S., "Key words for use in RFCs to Indicate Requirement 1685 Levels", BCP 14, RFC 2119, March 1997. 1687 [7] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", 1688 RFC 2246, January 1999. 1690 [8] Stewart, R., Xie, Q., Morneault, K., Sharp, C., Schwarzbauer, 1691 H., Taylor, T., Rytina, I., Kalla, M., Zhang, L., and V. 1692 Paxson, "Stream Control Transmission Protocol", RFC 2960, 1693 October 2000. 1695 [9] Jungmaier, A., Rescorla, E., and M. Tuexen, "TLS over SCTP", 1696 RFC 3436, December 2002. 1698 [10] Bellovin, S., Ioannidis, J., Keromytis, A., and R. Stewart, "On 1699 the Use of Stream Control Transmission Protocol (SCTP) with 1700 IPsec", RFC 3554, July 2003. 1702 [11] Stewart, R., Xie, Q., Stillman, M., and M. Tuexen, "Aggregate 1703 Server Access Protocol (ASAP) and Endpoint Handlespace 1704 Redundancy Protocol (ENRP) Parameters", 1705 draft-ietf-rserpool-common-param-09 (work in progress), 1706 July 2005. 1708 [12] Stillman, M., Gopal, R., Sengodan, S., Guttman, E., and M. 1709 Holdrege, "Threats Introduced by Rserpool and Requirements for 1710 Security in Response to Threats", 1711 draft-ietf-rserpool-threats-05 (work in progress), July 2005. 1713 7.2. Informative References 1715 [13] Eastlake, D., Crocker, S., and J. Schiller, "Randomness 1716 Recommendations for Security", RFC 1750, December 1994. 1718 Authors' Addresses 1720 Qiaobing Xie 1721 Motorola, Inc. 1722 1501 W. Shure Drive, 2-F9 1723 Arlington Heights, IL 60004 1724 US 1726 Phone: 1727 Email: qxie1@email.mot.com 1729 Randall R. Stewart 1730 Cisco Systems, Inc. 1731 4875 Forest Drive 1732 Suite 200 1733 Columbia, SC 29206 1734 USA 1736 Phone: 1737 Email: rrs@cisco.com 1739 Maureen Stillman 1740 Nokia 1741 127 W. State Street 1742 Ithaca, NY 14850 1743 US 1745 Phone: 1746 Email: maureen.stillman@nokia.com 1748 Michael Tuexen 1749 Muenster Univ. of Applied Sciences 1750 Stegerwaldstr. 39 1751 48565 Steinfurt 1752 Germany 1754 Email: tuexen@fh-muenster.de 1755 Aron J. Silverton 1756 Motorola, Inc. 1757 1301 E. Algonquin Road 1758 Room 2246 1759 Schaumburg, IL 60196 1760 USA 1762 Phone: +1 847-576-8747 1763 Email: aron.j.silverton@motorola.com 1765 Full Copyright Statement 1767 Copyright (C) The Internet Society (2006). 1769 This document is subject to the rights, licenses and restrictions 1770 contained in BCP 78, and except as set forth therein, the authors 1771 retain all their rights. 1773 This document and the information contained herein are provided on an 1774 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 1775 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET 1776 ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, 1777 INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE 1778 INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 1779 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 1781 Intellectual Property 1783 The IETF takes no position regarding the validity or scope of any 1784 Intellectual Property Rights or other rights that might be claimed to 1785 pertain to the implementation or use of the technology described in 1786 this document or the extent to which any license under such rights 1787 might or might not be available; nor does it represent that it has 1788 made any independent effort to identify any such rights. 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