idnits 2.17.1 draft-fedyk-ccamp-l1vpn-extnd-overlay-01.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** The abstract seems to contain references ([RFC4208], [RFC4847]), which it shouldn't. Please replace those with straight textual mentions of the documents in question. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (October 22, 2012) is 4175 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Obsolete informational reference (is this intentional?): RFC 5996 (Obsoleted by RFC 7296) -- Obsolete informational reference (is this intentional?): RFC 4835 (Obsoleted by RFC 7321) Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group D. Fedyk 3 Internet Draft D. Beller 4 Intended status: Standards Track Lieven Levrau 5 Alcatel-Lucent 6 D. Ceccarelli 7 Ericsson 8 F. Zhang 9 Huawei Technologies 10 Y. Tochio 11 Fujitsu 13 Expires: April 2013 October 22, 2012 15 Overlay Extension Service Model 16 draft-fedyk-ccamp-l1vpn-extnd-overlay-01.txt 18 Status of this Memo 20 This Internet-Draft is submitted in full conformance with the 21 provisions of BCP 78 and BCP 79. 23 Internet-Drafts are working documents of the Internet Engineering 24 Task Force (IETF), its areas, and its working groups. Note that 25 other groups may also distribute working documents as Internet- 26 Drafts. 28 Internet-Drafts are draft documents valid for a maximum of six months 29 and may be updated, replaced, or obsoleted by other documents at any 30 time. It is inappropriate to use Internet-Drafts as reference 31 material or to cite them other than as "work in progress." 33 The list of current Internet-Drafts can be accessed at 34 http://www.ietf.org/ietf/1id-abstracts.txt 36 The list of Internet-Draft Shadow Directories can be accessed at 37 http://www.ietf.org/shadow.html 39 This Internet-Draft will expire on April 25, 2013. 41 Copyright Notice 43 Copyright (c) 2012 IETF Trust and the persons identified as the 44 document authors. All rights reserved. 46 This document is subject to BCP 78 and the IETF Trust's Legal 47 Provisions Relating to IETF Documents 48 (http://trustee.ietf.org/license-info) in effect on the date of 49 publication of this document. Please review these documents 50 carefully, as they describe your rights and restrictions with respect 51 to this document. Code Components extracted from this document must 52 include Simplified BSD License text as described in Section 4.e of 53 the Trust Legal Provisions and are provided without warranty as 54 described in the Simplified BSD License. 56 Abstract 58 This document builds on the GMPLS overlay model [RFC4208] and defines 59 extensions to the GMPLS User-Network Interface (UNI) to support route 60 diversity within the core network for sets of LSPs initiated by edge 61 nodes. A particular example where route diversity within the core 62 network is desired, are dual-homed edge nodes. The document also 63 defines GMPLS UNI extensions to deal with latency requirements for 64 edge node initiated LSPs. 66 This document is also applicable to the L1VPN framework [RFC4847] to 67 extend the L1VPN from the basic mode to the enhanced mode by 68 including additional constraints, focusing upon the overlay extension 69 service model. Route Diversity for customer LSPs are common 70 requirement applicable to L1VPNs. This document describes L1VPN 71 compatible mechanisms to achieve diversity for sets of customer LSPs. 72 The extended overlay service model can support other extensions for 73 L1VPN signaling, for example, those related to latency requirements. 75 Table of Contents 77 1. Introduction...................................................3 78 2. Conventions used in this document..............................3 79 3. Contributors...................................................3 80 4. LSP Diversity in the Overlay Extension Service Model...........4 81 4.1. LSP diversity for dual-homed customer edge (CE) devices...5 82 4.1.1. Exchanging SRLG information between the PEs via the CE 83 device......................................................7 84 4.1.1.1. Operational Procedures..........................8 85 4.1.1.2. Error handling procedures.......................8 86 4.1.2. Using Path Affinity Set extension....................9 87 4.1.2.1. Operational Procedures.........................12 88 4.1.2.2. Error handling procedures......................13 89 4.1.2.3. Distribution of the Path Affinity Set information 90 ........................................................13 91 5. Latency signaling.............................................14 92 6. Security Considerations.......................................14 93 7. IANA Considerations...........................................15 94 8. References....................................................15 95 8.1. Normative References.....................................15 96 8.2. Informative References...................................15 97 9. Acknowledgments...............................................16 99 1. Introduction 101 This document builds on the GMPLS overlay model [RFC4208] and defines 102 extensions to the GMPLS User-Network Interface (UNI) to support route 103 diversity within the core network for sets of LSPs initiated by edge 104 nodes. In the following, the term customer edge (CE) device node is 105 used synonymously for the term edge node (EN) as in [RFC4208]. 106 Moreover, the L1VPN terminology is used below when the core network 107 as in [RFC4208] is described. 109 The document is also applicable to the L1VPN framework [RFC4847] to 110 extend the L1VPN from the basic mode to the enhanced mode by 111 including additional constraints, focusing upon the overlay extension 112 service model. 114 The overlay model assumes a UNI interface between the edge nodes of 115 the respective transport domains. Route diversity for LSPs from 116 single homed CE and dual-home CEs is a common requirement in optical 117 transport networks. This document describes two signaling variations 118 that may be used for supporting LSP diversity within the overlay 119 extension service model considering dual-homing. Dual-homing is 120 typically used to avoid a single point of failure (UNI link, PE) or 121 if two disjoint connections are forming a protection group. While 122 both methods are similar in that they utilize common mechanisms in 123 the PE network to achieve diversity, they are distinguished according 124 to whether the CE is permitted to retrieve provider SRLG diversity 125 information for an LSP from a PE1 and pass it on to a PE2 (SRLG 126 information is shared with the CE), or whether a new attribute is 127 used that allows the PE2 that receives this attribute to derive the 128 SRLG information for an LSP based on this attribute value. 130 The extended overlay service model can support other extensions for 131 L1VPN signaling, for example, those related to latency. When 132 requesting diverse LSPs latency may also be an additional 133 requirement. 135 2. Conventions used in this document 137 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 138 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 139 document are to be interpreted as described in RFC-2119 [RFC2119]. 141 In this document, these words will appear with that interpretation 142 only when in ALL CAPS. Lower case uses of these words are not to be 143 interpreted as carrying RFC-2119 significance. 145 3. Contributors 147 The Authors would like to thank Eve Varma and Sergio Belotti for 148 their review and contributions to this document. 150 4. LSP Diversity in the Overlay Extension Service Model 152 The L1VPN Framework [RFC4847] (Enhanced Mode) describes the overlay 153 extension service model, which builds upon the UNI Overlay [RFC4208] 154 serving as the interface between the CE edge node and the PE edge 155 node. In this service model, a CE receives a list of CE-PE TE link 156 addresses to which it can request a L1VPN connection (i.e., 157 membership information) and may include additional information 158 concerning these TE links. This document further builds on the 159 overlay extension service model by adding shared constraint 160 information for path diversity in the optical transport network. 162 This document describes two signaling variations that may be used for 163 supporting LSP diversity within the overlay extension service model 164 considering dual-homing. While both methods are similar in that they 165 utilize common mechanisms in the PE network to achieve diversity, 166 they are distinguished according to whether the CE is permitted to 167 retrieve provider SRLG diversity information for an LSP from a PE1 168 and pass it on to a PE2 (SRLG information is shared with the CE or 169 whether a new attribute is used that allows the PE2 that receives 170 this attribute to derive the SRLG information for an LSP based on 171 this attribute value. The selection between these methods is governed 172 by both PE-network specific policies and approaches taken (i.e., in 173 terms of how the provider chooses to perform routing internal to 174 their network). 176 The first method (see 3.1.1) assumes that provider Shared Resource 177 Link Group (SRLG) Identifier information is both available and 178 shareable (policy decision) with the CE. Since SRLG IDs can then be 179 used (passed transparently between PEs via the dual-homed CE) as 180 signaled information on a UNI message, a mechanism supporting LSP 181 diversity for the overlay extension service model can be provided via 182 straightforward signaling extensions. 184 The second method (see 3.1.2) assumes that provider SRLG IDs are 185 either not available or not shareable (based on provider network 186 operator policy) with the CE. For this case, a mechanism is provided 187 where information signaled to the PE on UNI messages does not require 188 shared knowledge of provider SRLG IDs to support LSP diversity for 189 the overlay extension model. 191 Both approaches follow the L1VPN framework. 193 While both methods could be implemented in the same PE network, it is 194 likely that an L1VPN CE network would use only one mechanism at a 195 time. 197 4.1. LSP diversity for dual-homed customer edge (CE) devices 199 Single-homed CE devices are connected to a single PE device via a 200 single UNI link (could be a bundle of parallel links which are 201 typically using the same fiber cable). This single UNI link may 202 constitute a single point of failure. Such a single point of failure 203 can be avoided when the CE device is connected to two PE devices via 204 two UNI interfaces as depicted for CE1 in Figure 1 below. 206 For the dual-homing case, it is possible to establish two connections 207 from the source CE device to the same destination CE device where one 208 connection is using one UNI link to, for example, PE1 and the other 209 connection is using the UNI link to PE2. In order to avoid single 210 points of failure within the provider network, it is necessary to 211 also ensure path (LSP) diversity within the provider network in order 212 to achieve end-to-end diversity for the two LSPs between the two CE 213 devices. This document describes how it is possible to enable such 214 path diversity to be achieved within the provider network (which is 215 subject to additional routing constraints). [RFC4202] defines SRLG 216 information that can be used to allow GMPLS to provide path diversity 217 in a GMPLS controlled transport network. As the two connections are 218 entering the provider network at different PE devices, the PE device 219 that receives the connection request for the second connection needs 220 to be capable of determining the additional path computation 221 constraints such that the path of the second LSP is disjoint with 222 respect to the already established first connection entering the 223 network at a different PE device. The methods described in this 224 document allow a PE device to determine the SRLG information for a 225 connection in the provider network that is entering the network on a 226 different PE device. 228 PE SRLG information can be used directly by a CE if the CE 229 understands the context, and the CE view is limited to its L1VPN 230 context. In this case, there is a dependency on the provider 231 information and there is a need to be able to query the SRLG in the 232 provider network. 234 It may, on the other hand, be preferable to avoid this dependency and 235 to decouple the SRLG identifier space used in the provider network 236 from the SRLG space used in the client network. This is possible with 237 both methods detailed below. Even for the method where provider SRLG 238 information is passing through the CE device (note the CE device does 239 not need to process and decode this information) the two SRLG 240 identifier spaces can remain fully decoupled and the operator of the 241 client network is free to assign SRLG identifiers from the client 242 SRLG identifier space to the CE to CE connection that is passing 243 through the provider network. 245 Referring to Figure 1, the UNI signaling mechanism must support at 246 least one of the two mechanisms described in this document for CE 247 dual homing to achieve LSP diversity in the provider network. 249 The described mechanisms can also be applied to a scenario where two 250 CE devices are connected to two different PE devices. In this case, 251 the additional information that is exchanged across the UNI 252 interfaces also needs to be exchanged between the two CE devices in 253 order to achieve the desired diversity in the provider network. 255 This information may be configured or exchanged by some automated 256 mechanism not described in this document. 258 In the dual-homing example, CE1 can locally correlate the LSP 259 requests. For the slightly more complicated example involving CE2 and 260 CE3, both requiring a path that shall be diverse to a connection 261 initiated by the other CE device, CE2 and CE3 need to have a common 262 view of the SRLG information to be signaled. In this document, we 263 detail the required diversity information and the signaling of this 264 diversity information; however, the means for distributing this 265 information within the PE domain or the CE domain is out of scope. 267 +---+ +---+ 268 | P |....| P | 269 +---+ +---+ 270 / \ 271 +-----+ +-----+ +---+ 272 +---+ | PE1 | | |----| | 273 |CE1|----| | | | |CE2| 274 +---+\ +-----+ | |----| | 275 \ | | PE3 | +---+ 276 \ +-----+ | | 277 \| PE2 | | | +---+ 278 | | | |----|CE3| 279 +-----+ +-----+ +---+ 280 \ / 281 +---+ +---+ 282 | P |....| P | 283 +---+ +---+ 285 Figure 1: Generalized Layer 1 VPN Reference Model 287 Figure 1 Overlay Reference Diagram 289 In an overlay model, the information exchanged between the CE and the 290 PE is kept to a minimum. 292 How diversity is achieved, in terms of configuration, distribution 293 and usage in each part of the transport networks should be kept 294 independent and separate from how diversity is signaled at the UNI 295 between the two transport networks. 297 Signaling parameters discussed in this document are: 299 o SRLG information (see [RFC4202]) 301 o Path Affinity Set 303 4.1.1. Exchanging SRLG information between the PEs via the CE device 305 SRLG information is defined in [RFC4202] and if the SRLG information 306 of an LSP is known, it can be used to calculate a path for another 307 LSP that is SRLG diverse with respect to an existing LSP. SRLG 308 information is an unordered list of SRLGs. SRLG information is 309 normally not shared between the transport network and the client 310 network; i.e., not shared with the CEs of a L1VPN in the L1VPN 311 context. However, this becomes more challenging when a CE is dual- 312 homed. For example, CE1 in Figure 1 may have requested an LSP1 from 313 CE1 to CE2 via PE1 and PE3. CE1 could subsequently request an LSP2 314 to CE2 via PE2 and PE3 with the requirement that it should be 315 maximally SRLG disjoint with respect to LSP1. Since PE2 does not have 316 any information about LSP1, PE2 would need to know the SRLG 317 information associated with LSP1. If CE1 could request the SRLG 318 information of LSP1 from PE1, it could then transparently pass this 319 information to PE2 as part of the LSP2 setup request, and PE2 would 320 now be capable of calculating a path for LSP2 that is SRLG disjoint 321 with respect to LSP1. 323 The exchange of SRLG information is achieved on a per L1VPN LSP basis 324 using the existing RSVP-TE signaling procedures. It can be exchanged 325 in the PATH (exclusion information) or RESV message in the original 326 request or it can be requested by the CE at any time the path is 327 active. 329 It shall be noted that SRLG information is an unordered list of SRLG 330 identifiers and the encoding of SRLG information for RSVP signaling 331 is already defined in [SRLG_info]. Even if SRLG information is known 332 for several LSPs it is not possible for the CEs to derive the 333 provider network topology from this information. 335 4.1.1.1. Operational Procedures 337 Retrieving SRLG information from a PE for an existing LSP: 339 When a dual-homed UNI-C intends to establish an LSP to the same 340 destination UNI-C via another PE node, it can request the SRLG 341 information for an already established LSP by setting the SRLG 342 information flag in the LSP attributes sub-object of the RSVP PATH 343 message (IANA to assign the new SRLG flag). As long as the SRLG 344 information flag is set in the PATH message, the PE node inserts the 345 SRLG sub-object as defined in [SRLG_info] into the RSVP RESV message 346 that contains the current SRLG information for the LSP. If the 347 provider network's policy has been configured so as not to share SRLG 348 information with the client network, the SRLG sub-object is not 349 inserted in the PATH message even if the SRLG information flag is 350 set. The PE passes on the SRLG information for the LSP. Note the 351 SRLG information is expected to be up-to-date. 353 Establishment of a new LSP with SRLG diversity constraints: 355 When a dual-homed CE device sends an LSP setup requests to a PE 356 device for a new LSP that is required to be SRLG diverse with respect 357 to an existing LSP that is entering the network via another PE 358 device, the UNI-C sets the SRLG diversity flag (note: IANA to assign 359 the new SRLG diversity flag) in the LSP attributes sub-object of the 360 PATH message that initiates the setup of this new LSP. When the PE 361 device receives this request it calculates a path to the given 362 destination and uses the received SRLG information as path 363 computation constraints. 365 4.1.1.2. Error handling procedures 367 To be added in the next version of the document. 369 4.1.2. Using Path Affinity Set extension 371 The Path Affinity Set (PAS) is used to signal diversity in a pure CE 372 context by abstracting SRLG information. There are two types of 373 diversity information in the PAS. The first type of information is a 374 single PAS identifier. Optionally, more detailed PATH information of 375 an exclude path or set of paths can be specified. The motive behind 376 the PAS information is to have as little exchange of diversity 377 information as possible between the L1VPN CE and PE elements. 379 Rather than a detailed CE or PE SRLG list, the Path Affinity Set 380 contains an abstract SRLG identifier that associates the given path 381 as diverse. Logically the identifier is in an L1VPN context and 382 therefore only unique with respect to a particular L1VPN. 384 How the CE determines the PAS identifier is a local matter for the CE 385 administrator. A CE may signal PAS as a diversity object in the PATH 386 message. This identifier is a suggested identifier and may be 387 overridden by a PE under some conditions. 389 For example, PAS can be used with no prior exchange of PAS 390 information between the CE and the PE. Upon reception of the PAS 391 information the PE can infer the CEs requirements. The actual PAS 392 identifier used will be returned in the RESV message. Optionally an 393 empty PAS identifier allows the PE to pick the PAS identifier. 394 Similar to the section 4.1.1 on SRLG information, a PE can return PAS 395 identifier as the response to a Query allowing flexibility. 397 A PE interprets the specific PAS identifier, for example, "123" as 398 meaning to exclude that identifier and by association any PE related 399 SRLG information, for any LSPs associated with the resources assigned 400 to the L1VPN. For example, if a Path exists for the LSP with the 401 identifier "123", the PE would use local knowledge of the PE SRLGs 402 associated with the "123" LSPs and exclude those SRLGs in the path 403 request. In other words, two LSPs that need to be diverse both 404 signal "123" and the PEs interpret this as meaning not to use shared 405 resources. Alternatively, a PE could use the PAS identifier to 406 select from already established LSPs. Once the path is established it 407 becomes associated with the "123" identifier or optionally another 408 PAS identifier for that L1VPN. 410 The PAS Source and Destination Address tuple represents one or more 411 source addresses and destination addresses associated with the CE 412 Path Affinity Set identifier. These associated address tuples 413 represent paths that use resources that should be excluded for the 414 establishment of the current LSP. The address tuple information 415 gives both finer grain details on the path diversity request and 416 serves as an alternative identifier in the case when the PAS 417 identifier is not known by the PE. The address tuples used in 418 signaling is within a CE context and its interpretation is local to a 419 PE that receives a Path request from a CE. The PE can use the address 420 information to relate to PE Addresses and PE SRLG information. When 421 a PE satisfies a connection setup for a (SRLG) diverse signaled path, 422 the PE may optionally record the PE SRLG information for that 423 connection in terms of PE based parameters and associate that with 424 the CE addresses in the Path message. 426 The L1VPN Port Information table (PIT) [RFC5251] can be leveraged to 427 translate between CE based addresses and PE based addresses. The Path 428 Affinity Set and associated PE addresses with PE SRLG information can 429 be distributed via the IGP in the provider transport network (or by 430 other means such as configuration); they can be utilized by other PEs 431 when other CE Paths are setup that would require path/connection 432 diversity. This information is distributed on a L1VPN basis and 433 contains a PAS identifier, PE addresses and SRLG information. 435 The CE Path Affinity Set may be used to signal paths without CE 436 Source and Destination addresses; however, the PE will always 437 associate the CE SRLG Group with a list of PE SRLG plus the PE 438 addresses associated with this LSP. 440 If diversity is not signaled, the assumption is that no diversity is 441 required and the Provider network is free to route the LSP to 442 optimize traffic. No Path affinity set information needs to be 443 recorded for these LSPs. If a diversity object is included in the 444 connection request, the PE in the Provider Network should be able to 445 look-up the existing Provider SRLG information from the provider 446 network and choose an LSP that is maximally diverse from other LSPs. 447 The mechanisms to achieve this are outside the scope of this 448 document. 450 A new L1VPN Diverse LSP LABEL object is specified: 452 0 1 2 3 453 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 1 454 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 455 | Length | Type (TBA) |0| C-type (TBA)| 456 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 458 1 2 3 459 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 1 461 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 462 | ADDR Length |Number of PAS |D| reserved | 463 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 464 | Path Affinity Set identifier | 465 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 466 | Source Address (variable) | 467 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 468 | Destination Address (variable) | 469 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 471 Figure 2 Diverse LSP information 473 1. The Address Length field (8 bits) is the number of bytes for both 474 the source address and destination address. The address may be in 475 any format from 1 to 32 bytes but the key point is the customers 476 can maintain their existing addresses. A value of zero indicates 477 there are no addresses included. 479 2. The Number of Path Affinity (8 bits)sets is included in the 480 object. This is typically 1. Addition of other sets is for further 481 study. 483 3. The Path affinity Set identifier (4 bytes) is a single number that 484 represents a summarized SRLG for this path. Paths with that same 485 Path Affinity set should be set up with diverse paths and 486 associated with the path affinity set. A value of all zeros 487 allows the PE to pick a PAS identifier to return. A PAS 488 identifier of an established path may be different than the 489 requested path identifier. 491 4. The diversity Bit (D) (one Bit) indicates if the diversity must be 492 satisfied when set as a one. If a PE finds an established path 493 with a Path Affinity set matching the signaled Path Affinity Set 494 or the signaled Address tuple it should attempt find a diverse 495 path. 497 5. The Diverse Path Source address/destination address tuple is that 498 of an established LSP in the PE network that belongs to the same 499 Path Affinity Set identifier. If the path for these addresses is 500 not setup or cannot be determined by the PE edge processing the 501 UNI then the path is only with the Path Affinity set constraint. 502 If the path(s) for these address tuples are known by the PE the PE 503 uses the SRLG information associated with these addresses. If in 504 any case a diverse path cannot be setup then the Diverse bit 505 controls whether a path is established anyway. The PE must use a 506 mechanism to translate CE Addresses into provider addresses when 507 correlating with provider SRLG information. How SRLG information 508 and network address tuples are distributed is for future study. 510 4.1.2.1. Operational Procedures 512 When a UNI-C constructs a PATH message it may optionally specify and 513 insert a Path Affinity Set in the PATH message. This Path Affinity 514 Set may optionally include the address of an LSP that that could 515 belong to the same Path Affinity Set. The Path Affinity Set 516 identifier is a value (0 through 2**32-255) that is independent of 517 the mechanism the CE or the PE use for diversity. The Path Affinity 518 Set is a single identifier that can be used to request diversity and 519 associate diversity. 521 When processing a CE PATH message in a L1VPN Overlay, the PE first 522 looks up the PE based addresses in the Provider Index Table (PIT). If 523 the Path Affinity Set is included in the PATH message, the PE must 524 look up the SRLG information (or equivalent) in the PE network that 525 has been allocated by LSPs associated with a Path Affinity Set and 526 exclude those resources from the path computation for this LSP if it 527 is a new path. The PE may alternatively choose from an existing path 528 with a disjoint set of resources. If a path that is disjoint cannot 529 be found, the value of the PAS diversity bit determines whether a 530 path should be setup anyway. If the PAS diversity bit is clear, one 531 can still attempt to setup the LSP. A PE should still attempt to 532 minimize shared resources but that is an implementation issue, and is 533 outside the scope of this document. 535 Optionally the CE may use a value of all zeros in the PAS identifier 536 allowing the PE to select an appropriate PAS identifier. Also the PE 537 may to override the PAS identifier allowing the PE to re-assign the 538 identifier if required. A CE should not assume that the PAS 539 identifier used for setup is the actual PAS identifier. 541 4.1.2.2. Error handling procedures 543 The PAS object must be understood by the PE device. Otherwise, the CE 544 should not use the PAS object. Path Message processing of the PAS 545 object SHOULD follow CTYPE 0. An Error code of IANA (TBD) indicates 546 that the PAS object is not understood. 548 When a PAS identifier is not recognized by a PE it must assume this 549 LSP defines that PAS identifier however the PE may override PAS 550 identifier under certain conditions. 552 If the identifier is recognized but the Source Address-Destination 553 address pair(s) are not recognized, this LSP must be set up using the 554 PAS identifier only. 556 If the identifier is recognized and the Source Address-Destination 557 address pair(s) are also recognized, then the PE SHOULD use the PE 558 SRLG information associated with the LSPs identified by the address 559 pairs to select a disjoint path. 561 The Following are the additional error codes: 563 1) Route Blocked by Exclude Route Value IANA (TBA). 565 4.1.2.3. Distribution of the Path Affinity Set information 567 Information about SRLG is already available in the IGP TE database. A 568 PE network can be designed to have additional opaque records for 569 Provider paths that distribute PE paths and SRLG on a L1VPN basis. 570 When a PE path is setup, the following information allows a PE to 571 lookup the PE diversity information: 573 - L1 VPN Identifier 8 bytes 574 - Path Affinity Set Identifier 575 - Source PE Address 576 - Destination PE Address 577 - List of PE SRLG (variable) 579 The source PE address and destination PE address are the same 580 addresses in the L1VPN PIT and correspond to the respective CE 581 address identifiers. 583 Note that all of the information is local to the PE context and is 584 not shared with the CE. The L1VPN Identifier is associated with a CE. 585 The only value that is signaled from the CE is the Path Affinity Set 586 and optionally the addresses of an existing LSP. The PE stores source 587 and destination PE addresses of the LSP in their native format along 588 with the SRLG information. This information is internal to the PE 589 network and is always known. 591 PE paths may be setup on demand or they may be pre-established. When 592 paths are pre-established, the Path Affinity Set is set to unassigned 593 0x0000 and is ignored. When a CE uses a pre-established path the PE 594 may set the Path SRLG Path Affinity Set value if the CE signals one 595 otherwise the Path Affinity Set remains unassigned 0x0000. 597 5. Latency signaling 599 A latency requirement can be added to signaling in the form of a 600 constraint [DRAFT OBJECTIVE FUNCTION]. The constraint can take the 601 form of: 603 - Minimize latency 605 - Maximum acceptable 607 While some systems may be able to compute routes based on delay 608 metrics it is usual that minimizing hops subject to bandwidth 609 reservation are satisfied as the object function and delay is not 610 considered. When considering diversity latency falls after diversity 611 constraints have been satisfied. 613 Recording the latency of existing paths [DRAFT_TE_METRIC RECORD] to 614 ensure they meet a maximum acceptable latency can be utilized to 615 ensure latency constraint is met. 617 When a low latency path is required, the minimize latency subject to 618 other constraints criteria should be signaled. A CE device can use 619 the record latency to ensure that the maximum acceptable latency has 620 been met. 622 More detail to be added in a future revision. 624 6. Security Considerations 626 Security for L1VPNs is covered in [RFC4847], [RFC5251] and [RFC5253]. 627 In this document, the model follows the L1VPN control plane model 628 where CE addresses are completely distinct from the PE addresses. 630 The use of a private network assumes that entities outside the 631 network cannot spoof or modify control plane communications between 632 CE and PE. Furthermore, all entities in the private network are 633 assumed to be trusted. Thus, no security mechanisms are required by 634 the protocol exchanges described in this document. 636 However, an operator that is concerned about the security of their 637 private control plane network may use the authentication and 638 integrity functions available in RSVP-TE [RFC3473] or utilize IPsec 639 ([RFC4301], [RFC4302], [RFC4835], [RFC5996], and [RFC6071]) for the 640 point-to-point signaling between PE and CE. See [RFC5920] for a full 641 discussion of the security options available for the GMPLS control 642 plane. 644 7. IANA Considerations 646 TBD 648 8. References 650 Normative References 652 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 653 Requirement Levels", BCP 14, RFC 2119, March 1997. 655 [RFC4202] Kompella, K., Rekhter, Y., "Routing Extensions in Support 656 of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 657 4202, October 2005. 659 [RFC4208] G. Swallow, J. Drake, H. Ishimatsu, Y. Rekhter, 660 "Generalized Multiprotocol Label Switching (GMPLS) User- 661 Network Interface (UNI): Resource ReserVation Protocol- 662 Traffic Engineering (RSVP-TE) Support for the Overlay 663 Model", RFC 4208, October 2005. 665 [RFC5251] Fedyk, D., Rekhter, Y., Editors "Layer 1 VPN Basic Mode", 666 RFC 5251, July 2008. 668 [SRLG_info] Zhang, F., Li, D., Gonzalez de Dios, O., Margaria, C., 669 "RSVP-TE Extensions for Collecting SRLG Information", 670 draft-ietf-ccamp-rsvp-te-srlg-collect-00.txt, June 2012. 672 8.2. Informative References 674 [RFC6071] S. Frankel, S. Krishnan, " IP Security (IPsec) and Internet 675 Key Exchange (IKE) Document Roadmap", RFC 6071, February 676 2011. 678 [RFC3473] Berger, L. (editor), "Generalized MPLS Signaling - RSVP-TE 679 Extensions", RFC 3473, January 2003. 681 [RFC4301] S. Kent, K. Seo, "Security Architecture for the Internet 682 Protocol," December 2005. 684 [RFC4302] S. Kent, "IP Authentication Header," December 2005. 686 [RFC5996] C. Kaufman, P. Hoffman, Y. Nir, P. Eronen " Internet Key 687 Exchange Protocol Version 2 (IKEv2)", September 2010. 689 [RFC4835] V. Manral, "Cryptographic Algorithm Implementation 690 Requirements for Encapsulating Security Payload (ESP) and 691 Authentication Header (AH)", April 2007. 693 [RFC4847] Takeda, T., Editor "Framework and Requirements for Layer 1 694 Virtual Private Networks", RFC 4847, April 2007. 696 [RFC5253] Takeda, T., Editor "Applicability Statement for Layer 1 697 Virtual Private Network (L1VPN) Basic Mode", RFC 5253, July 698 2008. 700 [RFC5920] L. Fang, Ed., "Security Framework for MPLS and GMPLS 701 Networks", RFC 5920, July 2010. 703 [DRAFT OBJECTIVE FUNCTION] Ali, Z., Swallow, G., Filsfils, C., Fang, 704 L., Kumaki, K., Kunze, R.,"Resource ReserVation Protocol- 705 Traffic Engineering (RSVP-TE) extension for signaling 706 Objective Function and Metric Bound", draft-ali-ccamp-rc- 707 objective-function-metric-bound-02.txt, July 2012. 709 [DRAFT_TE_METRIC RECORD] Ali, Z., Swallow, G., Filsfils, C., Kumaki, 710 K., Kunze, R., "Resource ReserVation Protocol-Traffic 711 Engineering (RSVP-TE) extension for recording TE Metric of 712 a Label Switched Path", draft-ali-ccamp-te-metric- 713 recording-02.txt, July 2012. 715 9. Acknowledgments 717 Copyright (c) 2012 IETF Trust and the persons identified as authors 718 of the code. All rights reserved. 720 Redistribution and use in source and binary forms, with or without 721 modification, is permitted pursuant to, and subject to the license 722 terms contained in, the Simplified BSD License set forth in Section 723 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents 724 (http://trustee.ietf.org/license-info). 726 Authors' Addresses 728 Don Fedyk 729 Alcatel-Lucent 730 Groton, MA, 01450 731 Email: donald.fedyk@alcatel-lucent.com 733 Dieter Beller 734 Alcatel-Lucent 735 Email: Dieter.Beller@alcatel-lucent.com 737 Lieven Levrau 738 Alcatel-Lucent 739 Email: Lieven.Levrau@alcatel-lucent.com 741 Daniele Ceccarelli 742 Ericsson 743 Email: Daniele.Ceccarelli@ericsson.com 745 Fatai Zhang 746 Huawei Technologies 747 Email: zhangfatai@huawei.com 749 Yuji Tochio 750 Fujitsu 751 Email: tochio@jp.fujitsu.com