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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Missing Reference: 'MPLS-TP-22' is mentioned on line 436, but not defined == Unused Reference: 'RFC5654' is defined on line 419, but no explicit reference was found in the text == Unused Reference: 'RFC5921' is defined on line 421, but no explicit reference was found in the text == Unused Reference: 'RFC6372' is defined on line 423, but no explicit reference was found in the text == Unused Reference: 'RFC6378' is defined on line 427, but no explicit reference was found in the text == Unused Reference: 'RFC6974' is defined on line 431, but no explicit reference was found in the text Summary: 1 error (**), 0 flaws (~~), 8 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 MPLS Working Group G. Liu 3 Internet-Draft ZTE Corporation 4 Intended status: Informational Y. Weigarten 5 Expires: April 21, 2014 6 M. Daikoku 7 T. Maruyama 8 KDDI Corporation 9 October 18, 2013 11 MPLS-TP protection for interconnected rings 12 draft-liu-mpls-tp-interconnected-ring-protection-05 14 Abstract 16 The requirements for MPLS Transport Profile include a requirement 17 (R93) that requires MPLS-TP must support recovery mechanisms for a 18 network constructed from interconnected rings that protect user data 19 that traverses more than one ring. In particular, This includes 20 protecting against cases of failure at the ring-interconnect nodes 21 and links. This document presents different scenario of 22 interconnected rings and special mechanism to address recovery of the 23 failure of ring-interconnect nodes and links. . 25 This document is a product of a joint Internet Engineering Task 26 Force(IETF) / International Telecommunications Union 27 Telecommunications Standardization Sector (ITU-T) effort to include 28 an MPLS Transport Profile within the IETF MPLS and PWE3 architectures 29 to support the capabilities and functionalities of a packet transport 30 network as defined by the ITU-T. 32 Status of This Memo 34 This Internet-Draft is submitted in full conformance with the 35 provisions of BCP 78 and BCP 79. 37 Internet-Drafts are working documents of the Internet Engineering 38 Task Force (IETF). Note that other groups may also distribute 39 working documents as Internet-Drafts. The list of current Internet- 40 Drafts is at http://datatracker.ietf.org/drafts/current/. 42 Internet-Drafts are draft documents valid for a maximum of six months 43 and may be updated, replaced, or obsoleted by other documents at any 44 time. It is inappropriate to use Internet-Drafts as reference 45 material or to cite them other than as "work in progress." 47 This Internet-Draft will expire on April 21, 2014. 49 Copyright Notice 51 Copyright (c) 2013 IETF Trust and the persons identified as the 52 document authors. All rights reserved. 54 This document is subject to BCP 78 and the IETF Trust's Legal 55 Provisions Relating to IETF Documents 56 (http://trustee.ietf.org/license-info) in effect on the date of 57 publication of this document. Please review these documents 58 carefully, as they describe your rights and restrictions with respect 59 to this document. Code Components extracted from this document must 60 include Simplified BSD License text as described in Section 4.e of 61 the Trust Legal Provisions and are provided without warranty as 62 described in the Simplified BSD License. 64 This document may not be modified, and derivative works of it may not 65 be created, and it may not be published except as an Internet-Draft. 67 Table of Contents 69 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 70 2. Conventions used in this document . . . . . . . . . . . . . . 6 71 3. Recovery mechanism . . . . . . . . . . . . . . . . . . . . . 7 72 3.1. Recovery mechanism for Dual-node interconnection . . . . 7 73 3.2. Recovery mechanism for chained interconnection . . . . . 9 74 4. Security Considerations . . . . . . . . . . . . . . . . . . . 10 75 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 76 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10 77 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 78 7.1. Normative References . . . . . . . . . . . . . . . . . . 11 79 7.2. URL References . . . . . . . . . . . . . . . . . . . . . 11 80 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 82 1. Introduction 84 This document describes different interconnected ring scenario and a 85 few special mechanisms to protect against the failure of the ring- 86 interconnect nodes and links. There are three common interconnection 87 scenarios that we will address in this document: 89 Dual-node interconnection - when the two rings are interconnected by 90 two nodes from each ring (see Figure 1); 92 Single-node interconnection - when the connection between the two 93 rings is through a single node (see Figure 2).As the interconnnection 94 node(LSR-A) is a single-point of failure, this scenario should be 95 avoided in real network; 96 Chained interconnection - when a series of rings are connected 97 through interconnection nodes that are part of both interconnected 98 rings (see Figure 3) 100 /LSR\******/LSR\******/LSR\xxxx/LSR\*****/LSR\******/LSR\ 101 \_C_/ \_B_/ \_A_/ \_6_/ \_1_/ \_2_/ 102 * * x x * * 103 * Ring #1 * x x * Ring #2 * 104 _*_ ___ _*_ x _*_ ___ _*_ 105 /LSR\ /LSR\ /LSR\x x /LSR\ /LSR\ /LSR\ 106 \_D_/******\_E_/******\_F_/xxxx\_5_/*****\_4_/******\_3_/ 108 *** physical link 109 xxx interconnection link 111 Figure 1: Dual-node interconnection scenario 113 ___ ___ ___ ___ 114 /LSR\**********/LSR\ /LSR\*********/LSR\ 115 \_C_/ \_B_/* *\_1_/ \_2_/ 116 * * * * 117 * * * * 118 * * * * 119 _*_ * ___ * _*_ 120 /LSR\ Ring #1 /LSR\ Ring #2 /LSR\ 121 \_D_/ *\_A_/* \_3_/ 122 * * * * 123 * * * * 124 * * * * 125 _*_ ___* *___ _*_ 126 /LSR\ /LSR\ /LSR\ /LSR\ 127 \_E_/***********\_F_/ \_5_/**********\_4_/ 129 *** physical link 131 Figure 2: Single-node interconnection scenario 132 ___ ___ ___ ___ ___ 133 /LSR\******/LSR\******/LSR\*****/LSR\******/LSR\ 134 \_C_/ \_B_/ \_A_/ \_1_/ \_2_/ 135 * x * 136 * Ring #1 x Ring #2 * 137 _*_ ___ _x_ ___ _*_ 138 /LSR\ /LSR\ /LSR\ /LSR\ /LSR\ 139 \_D_/******\_E_/******\_F_/*****\_4_/******\_3_/ 141 *** physical link 142 xxx interconnection link 144 Figure 3: chained interconnected scenario 146 Considering a traffic that traveres more than two rings. Many 147 interconnection scenarios could be existed in the same scenario, They 148 will be mixed interconnection scenario; 150 Dual-node and single-node mixed interconnection- when there exists a 151 multi-ring traffic which traveres more than two rings. two of these 152 rings are dual-node interconnection. while another two are single- 153 node interconnection (see figure 5); 155 Dual-node and chained mixed interconnection-when there exist both 156 dual-node interconnection and chained interconnection in this 157 scenario (see figure 4); 159 single-node and chained mixed interconnection-when there exist both 160 single-node interconnection and chained interconnection in this 161 scenario(see figure 6); 163 Dual-node, single-node and chained mixed interconnection-when there 164 exist all three interconnection scenrios in this scenario including 165 Dual-node interconnnection, single-node interconnection and chained 166 interconnnection( see figure 7); 168 ___ 170 /LSR\******/LSR\xx/LSR\****/LSR\ /LSR\**** /LSR\***/LSR\ 171 \_C_/ \_B_/ \_A_/ \_6_/ \_1_/ \_2_/ \_H_/ 172 * * x x * * * x * 173 x * x * 174 * Ring 1 * x x * Ring 2 * .....*Ring 3 x Ring 4* 175 _*_ *x x_*_ _*_ ___ ___ ___ 176 /LSR\ /LSR\ /LSR\ /LSR\ /LSR\*****/LSR\**/LSR\ 177 \_D_/******\_E_/xx\_5_/*****\_4_/ \_k_/ \_L_/ \_M_/ 179 *** physical link 180 xxx interconnection link 182 Figure 4: Dual-node and chained mixed interconnect scenario 184 ___ 185 /LSR\******/LSR\xx/LSR\****/LSR\ /LSR\ /LSR\ 186 \_C_/ \_B_/ \_A_/ \_6_/ \_1_/ *\_H_/ 187 * * x x * * * * * * 188 x * * ___ * * 189 * Ring 1 * x x * Ring 2 * .....*Ring 3/LSR\ Ring 4* 190 _*_ *x x_*_ _*_ ___ * \_L_/* ___ 191 /LSR\ /LSR\ /LSR\ /LSR\ /LSR\* * /LSR\ 192 \_D_/******\_E_/xx\_5_/*****\_4_/ \_k_/ \_M_/ 194 *** physical link 195 xxx interconnection link 197 Figure 5: Dual-node and single-node mixed interconnect scenario 199 ___ 200 /LSR\******/LSR\**/LSR\****/LSR\ /LSR\ /LSR\ 201 \_C_/ \_B_/ \_A_/ \_6_/ \_1_/ *\_H_/ 202 * x * * * * * 203 * * ___ * * 204 * Ring 1 x Ring 2 * .....*Ring 3/LSR\ Ring 4* 205 _*_ _ _x_ _*_ ___ * \_L_/* ___ 206 /LSR\ /LSR\ /LSR\ /LSR\ /LSR\* * /LSR\ 207 \_D_/******\_E_/**\_5_/*****\_4_/ \_k_/ *\_M_/ 208 *** physical link 209 xxx interconnection link 211 Figure 6: Chained and single-node mixed interconnect scenario 213 ___ 214 /LSR\******/LSR\xx/LSR\****/LSR\**** /LSR\ /LSR\ 215 \_C_/ \_B_/ \_A_/ \_6_/ \_1_/ *\_H_/ 216 * * x x * x x * * * 217 x x * ___ * * 218 * Ring 1 * x x * Ring 2 xRing 5 xRing 3/LSR\ Ring 4* 219 _*_ *x x_*_ _x_ ___ * \_L_/* ___ 220 /LSR\ /LSR\ /LSR\ /LSR\****/LSR\* * /LSR\ 221 \_D_/******\_E_/xx\_5_/*****\_4_/ \_k_/ *\_M_/ 223 *** physical link 224 xxx interconnection link 226 Figure 7: Dual-node,chained and single-node mixed interconnect 227 scenario 229 For a multi-ring traffic, It will be across more than one ring just 230 like above seven scenarios. If a failure happens on a multi-ring 231 path, quick recovery is necessary requirement for multi-ring traffic. 233 2. Conventions used in this document 235 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 236 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 237 document are to be interpreted as described in RFC-2119. 239 OAM: Operations, Administration, Maintenance 241 LSP: Label Switched Path. 243 TLV: Type Length Value 245 PSC:Protection Switching Coordination 247 SD:Signal Degrade 248 SF:Signal Fail 250 MPLS-TP:Multi-Protocol Label Switching Transport Profile 252 3. Recovery mechanism 254 In the following subsection, It proposes different mechanism that may 255 be applied for traffic recovery for different interconnection 256 scenario. In general, It may be possible to provide protection 257 against the failure of a ring node/link by using a single-ring 258 protection mechanism. These cases are out of scope for this 259 document.At the same time, It is also possible to configure an end- 260 to-end protection path to protect a multi-ring traffic which will 261 across multi-ring. While this protection mechanism does not scale 262 very well. We need to consider special mechanism to address recovery 263 from failures of the interconnecting nodes and links 265 3.1. Recovery mechanism for Dual-node interconnection 267 Under this scenario , When interconnection link(LSRA-LSR6) has a 268 failure as shown in figure 8. it is possible use 1:1 linear 269 protection mechanism to protect the failure of segment(LSRA-LSR6) by 270 using one of the protection tunnels (LSRA-LSRF-LSR5-LSR6 or LSRA- 271 LSRF-LSR6 or LSRA-LSR5-LSR6) . 273 /LSR\******/LSR\******/LSR\x||x/LSR\*****/LSR\******/LSR\ 274 \_C_/ \_B_/ \_A_/ \_6_/ \_1_/ \_2_/ 275 * * x x * * 276 * Ring #1 * x x * Ring #2 * 277 _*_ ___ _*_ x _*_ ___ _*_ 278 /LSR\ /LSR\ /LSR\x x /LSR\ /LSR\ /LSR\ 279 \_D_/******\_E_/******\_F_/xxxx\_5_/*****\_4_/******\_3_/ 281 *** physical link 282 xxx interconnection link 283 || failure 285 Figure 8: interconnection link failure for dual-node interconnection 287 When the interconnection node(LSRA or LSR6) detects a SF or SD on the 288 interconnection link(LSRA-LSR6), LSRA or LSR6 will send SF or SD 289 failure message to its peer node. Then they push the multi-ring 290 traffic into its corresponding protection tunnel to another end 291 point(LSRA or LSR6) of the segment . When the peer node (LSR6 or 292 LSRA) receives the traffic packet from its protection tunnel, it will 293 POP the outer label of protection tunnel and return back to the 294 original working tunnel(LSRA-LSRB-LSRC or LSR6-LSR1-LSR2) of another 295 ring(ring 1 or ring 2) to transport the multi-ring traffic. 297 When the interconnection node(LSRA or LSR6) has a failure as shown in 298 figure 9. The end node of the segment detects the failure of the 299 interconnection node, It should send failure messge to the backup 300 interconnection node(LSRF or LSR5) to active its corresponding 301 protection path that goes to the backup interconnection node(LSRF or 302 LSR5) to trasnport the multi-ring traffic. At the same time, the 303 backup interconnection node should active its corresponding 304 protection path that goes to another primary interconnection 305 node(LSR6 or LSRA) of another ring.Then the multi-ring traffic should 306 return back to the original working path to be transported in another 307 ring. 309 ## 310 /LSR\******/LSR\******/LSR\xxxx/LSR\*****/LSR\******/LSR\ 311 \_C_/ \_B_/ \_A_/ \_6_/ \_1_/ \_2_/ 312 * * x x * * 313 * Ring #1 * x x * Ring #2 * 314 _*_ ___ _*_ x _*_ ___ _*_ 315 /LSR\ /LSR\ /LSR\x x /LSR\ /LSR\ /LSR\ 316 \_D_/******\_E_/******\_F_/xxxx\_5_/*****\_4_/******\_3_/ 318 *** physical link 319 xxx interconnection link 320 ## node failure 322 Figure 9: interconnection node failure for dual-node interconnection 324 For example , When LSRC directly detects or is informed of a failure 325 on the interconnection node LSRA. it will send a failure message to 326 notify the backup interconnection node LSRF to active its protection 327 path(LSRC-LSRD-LSRE-LSRF) to transport the multi-ring traffic.At the 328 same time, When LSRF receives the failure message from LSRC ,it 329 should still active its corresponding protection path that goes to 330 another primary interconnection node LSR6 to transport the multi-ring 331 traffic.The corresponding protection path may be one of the two paths 332 (LSRF-LSR5-LSR6 or LSRF-LSR6). Then the multi-ring traffic will be 333 transported by its original working path(LSR6-LSR1-LSR2) to another 334 peer node LSR2. 336 3.2. Recovery mechanism for chained interconnection 338 For this scenario , When only a failure is detected on the 339 interconnection link by interconnection node. since the failure 340 should not affect the multi-ring traffic. no action is need to be 341 taken. When a failure happens on the segment of the multi-ring path 342 and the interconnection link at the same time ,just as shown in 343 figure 10. The end node of the multi-ring path directly detects or 344 is informed of the two failures, Then it will active the protection 345 path that goes to the backup interconnection node to transport the 346 multi-ring traffic. After the backup interconnection node receives 347 the failure message , it will active its corresponding protection 348 path that goes to the end node of another ring 350 ___ ___ ___ ___ ___ 351 /LSR\**||**/LSR\******/LSR\*****/LSR\******/LSR\ 352 \_C_/ \_B_/ \_A_/ \_1_/ \_2_/ 353 * x * 354 * Ring #1 || Ring #2 * 355 _*_ ___ _x_ ___ _*_ 356 /LSR\ /LSR\ /LSR\ /LSR\ /LSR\ 357 \_D_/******\_E_/******\_F_/*****\_4_/******\_3_/ 359 *** physical link 360 xxx interconnection link 361 || failure 363 Figure 10: interconnection link failure for chained interconnected 364 scenario 366 For example, there are a failure on both link(LSRC-LSRB) and (LSRA- 367 LSRF) at the same time as shown in figure.10. When LSRC detects or 368 is notified of the segment failure on both the segment of ring 1 and 369 the interconnection link. It will send a failure message to the 370 backup interconnection node LSRF, Then LSRF will active its 371 corresponding protection path(LSRF-LSR4-LSR3-LSR2) of ring 2 to 372 transport the multi-ring traffic. 374 When a interconnection node has a failure for the chained 375 interconnection scenario, both peer node of the two rings will detect 376 the failure by segment OAM. So they should switch into the multi- 377 ring protection path to transport the multi-ring traffic. 379 ___ ___ _##_ ___ ___ 380 /LSR\******/LSR\******/LSR\*****/LSR\******/LSR\ 381 \_C_/ \_B_/ \_A_/ \_1_/ \_2_/ 382 * x * 383 * Ring #1 x Ring #2 * 384 _*_ ___ _x_ ___ _*_ 385 /LSR\ /LSR\ /LSR\ /LSR\ /LSR\ 386 \_D_/******\_E_/******\_F_/*****\_4_/******\_3_/ 388 *** physical link 389 xxx interconnection link 390 ## node failure 392 Figure 11: interconnection node failure for chained interconnected 393 scenario 395 Just as the failure scenario in figure 11. When an interconnection 396 node LSRA has a failure, the peer node(LSRC and LSR2) of ring 1 and 397 ring 2 must detect the node failure by segment OAM , Then they will 398 active protection switch and transport the protected multi-ring 399 traffic by its corresponding protection path(LSRC-LSRD-LSRE-LSRF- 400 LSR4-LSR3-LSR2) to LSR2. Then the protected traffic will return back 401 to the original working path to be transported. 403 4. Security Considerations 405 TBD 407 5. IANA Considerations 409 TBD. 411 6. Acknowledgments 413 TBD . 415 7. References 417 7.1. Normative References 419 [RFC5654] IETF, "MPLS-TP requirement ", September 2009. 421 [RFC5921] IETF, "MPLS-TP framework ", July 2010. 423 [RFC6372] N. Sprecher, A. Farrel, ., "Multiprotocol Label Switching 424 Transport Profile Survivability Framework", September 425 2011. 427 [RFC6378] S. Bryant, N. Sprecher, A. Fulignoli Y. Weingarten, ., 428 "MPLS transport profile Linear Protection", September 429 2011. 431 [RFC6974] Y. Weingarten,S. Bryant,D. Ceccarelli, ., "Applicability 432 of MPLS Transport Profile for Ring Topologies", July 2013. 434 7.2. URL References 436 [MPLS-TP-22] 437 IETF - ITU-T Joint Working Team, 2008, 438 . 440 Authors' Addresses 442 Guoman Liu 443 ZTE Corporation 444 No.50, Ruanjian Ave, Yuhuatai District 445 Nanjing 210012 446 P.R.China 448 Phone: +86 025 88014227 449 Email: liu.guoman@zte.com.cn 451 Yaacov Weingarten 452 34 Hagefen St Karnei 453 Shomron 44853 454 Israel 456 Phone: +972-9-775 1827 457 Email: wyaacov@gmail.com 458 Masahiro Daikoku 459 KDDI Corporation 460 Garden Air Tower,Iidabashi, Chiyoda-ku 461 Tokyo 102-8460 462 Japan 464 Email: ms-daikoku@kddi.com 466 Takeshi Maruyama 467 KDDI Corporation 468 Garden Air Tower,Iidabashi, Chiyoda-ku 469 Tokyo 102-8460 470 Japan 472 Email: ta-maruyama@kddi.com