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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force H. Chen 3 Internet-Draft Huawei Technologies 4 Intended status: Standards Track A. Liu 5 Expires: May 4, 2017 Ericsson 6 F. Xu 7 Verizon 8 M. Toy 9 Comcast 10 V. Liu 11 China Mobile 12 October 31, 2016 14 Extensions to PCEP for Distributing Label Cross Domains 15 draft-chen-pce-label-x-domains-05.txt 17 Abstract 19 This document specifies extensions to PCEP for distributing labels 20 crossing domains for an inter-domain Point-to-Point (P2P) or Point- 21 to-Multipoint (P2MP) Traffic Engineering (TE) Label Switched Path 22 (LSP). 24 Status of this Memo 26 This Internet-Draft is submitted in full conformance with the 27 provisions of BCP 78 and BCP 79. 29 Internet-Drafts are working documents of the Internet Engineering 30 Task Force (IETF). Note that other groups may also distribute 31 working documents as Internet-Drafts. The list of current Internet- 32 Drafts is at http://datatracker.ietf.org/drafts/current/. 34 Internet-Drafts are draft documents valid for a maximum of six months 35 and may be updated, replaced, or obsoleted by other documents at any 36 time. It is inappropriate to use Internet-Drafts as reference 37 material or to cite them other than as "work in progress." 39 This Internet-Draft will expire on May 4, 2017. 41 Copyright Notice 43 Copyright (c) 2016 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 Table of Contents 58 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 59 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 60 3. Conventions Used in This Document . . . . . . . . . . . . . . 4 61 4. Label Distribution . . . . . . . . . . . . . . . . . . . . . . 4 62 4.1. An Exmaple . . . . . . . . . . . . . . . . . . . . . . . . 4 63 5. Extensions to PCEP . . . . . . . . . . . . . . . . . . . . . . 5 64 5.1. RP Object Extension . . . . . . . . . . . . . . . . . . . 5 65 5.2. Label Object . . . . . . . . . . . . . . . . . . . . . . . 6 66 5.3. LSP Tunnel Object . . . . . . . . . . . . . . . . . . . . 7 67 5.4. Request Message Extension . . . . . . . . . . . . . . . . 9 68 5.5. Reply Message Extension . . . . . . . . . . . . . . . . . 9 69 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 70 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 71 7.1. Request Parameter Bit Flags . . . . . . . . . . . . . . . 10 72 8. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 10 73 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10 74 9.1. Normative References . . . . . . . . . . . . . . . . . . . 10 75 9.2. Informative References . . . . . . . . . . . . . . . . . . 11 76 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11 78 1. Introduction 80 After a path crossing multiple domains is computed, an inter-domain 81 Traffic Engineering (TE) Label Switched Path (LSP) tunnel may be set 82 up along the path by a number of tunnel central controllers (TCCs). 83 Each of the domains through which the path goes may be controlled by 84 a tunnel central controller (TCC), which sets up the segment of the 85 TE LSP tunnel in the domain. When the TCC sets up the segment of the 86 TE LSP tunnel in its domain that is not a domain containing the tail 87 end of the tunnel, it needs a label from a downstream domain, which 88 is next to it along the path. 90 This document specifies extensions to PCEP for distributing a label 91 from a domain to its upstream domain along the path for the TE LSP 92 tunnel crossing multiple domains. 94 2. Terminology 96 ABR: Area Border Router. Routers used to connect two IGP areas 97 (areas in OSPF or levels in IS-IS). 99 ASBR: Autonomous System Border Router. Routers used to connect 100 together ASes of the same or different service providers via one or 101 more inter-AS links. 103 Boundary Node (BN): a boundary node is either an ABR in the context 104 of inter-area Traffic Engineering or an ASBR in the context of 105 inter-AS Traffic Engineering. 107 Entry BN of domain(n): a BN connecting domain(n-1) to domain(n) along 108 a determined sequence of domains. 110 Exit BN of domain(n): a BN connecting domain(n) to domain(n+1) along 111 a determined sequence of domains. 113 Inter-area TE LSP: A TE LSP that crosses an IGP area boundary. 115 Inter-AS TE LSP: A TE LSP that crosses an AS boundary. 117 LSP: Label Switched Path. 119 LSR: Label Switching Router. 121 PCC: Path Computation Client. Any client application requesting a 122 path computation to be performed by a Path Computation Element. 124 PCE: Path Computation Element. An entity (component, application, or 125 network node) that is capable of computing a network path or route 126 based on a network graph and applying computational constraints. 128 PCE(i) is a PCE with the scope of domain(i). 130 TED: Traffic Engineering Database. 132 This document uses terminologies defined in RFC5440. 134 3. Conventions Used in This Document 136 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 137 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 138 document are to be interpreted as described in RFC2119. 140 4. Label Distribution 142 The Label Distribution may be provided by the PCE-based path 143 computation. A PCE responsible for a domain computes a path segment 144 for the domain, which is from an entry boundary to an exit boundary 145 (or an egress) node of the domain. The PCE gets an label from the 146 entry boundary node and adds an label object containing the label in 147 the reply message to be sent to the requesting PCC (or another PCE). 149 When a PCE or PCC receives a reply message containing an label 150 object, it removes the object from the message. The PCE may store 151 the information in the label object or send the information to 152 another component such as a Tunnel Central Controller (TCC). 154 4.1. An Exmaple 156 Figure 1 below illustrates a simple two-AS topology. There is a PCE 157 responsible for the path computation in each AS. A path computation 158 is requested from the Tunnel Central Controller (TCC), acting as the 159 PCC, which sends the path computation request to PCE-1. 161 PCE-1 is unable to compute an end-to-end path and invokes PCE-2 162 (possibly using the techniques described in [RFC5441]). PCE-2 163 computes a path segment from entry boundary node ASBR-2 of the right 164 domain to the egress as {ASBR-2, C, D, Egress}. 166 In addition to placing this path segment in the reply message to 167 PCE-1, PCE-2 gets an label from the entry boundary node ASBR-2 and 168 adds an label object containing the label and optionally the ASBR-2 169 into the reply message. 171 ------------------------------- ------------------------------ 172 | ------- | | ------- | 173 | +-->| PCE-1 |<---------+--+-->| PCE-2 | | 174 | | ------- | | ------- | 175 | v | | ^ | 176 | ----- | | | | 177 | | TCC | | | | | 178 | | PCC | | | | | 179 | ----- | | v | 180 | ------- - - ------ | | ------ - - ------ | 181 | |Ingress|--|A|--|B|--|ASBR-1|-+--+-|ASBR-2|--|C|--|D|--|Egress| | 182 | ------- - - ------ | | ------ - - ------ | 183 | | | | 184 ------------------------------- ------------------------------ 186 Figure 1: Example of Label Distribution 188 When PCE-1 receives the reply message containing the label object 189 from PCE-2, it removes the object from the message. PCE-1 may store 190 the information in the label object or send the information to 191 another component such as a Tunnel Central Controller (TCC). TCC may 192 set up the segment of the LSP tunnel from Ingress to ASBR-2 using the 193 label in the label object from ASBR-2. 195 5. Extensions to PCEP 197 This section describes the extensions to PCEP for distributing labels 198 crossing domains for an inter-domain Point-to-Point (P2P) or Point- 199 to-Multipoint (P2MP) Traffic Engineering (TE) Label Switched Path 200 (LSP). The extensions include the definition of a new flag in the RP 201 object, tunnel information and label in a PCReq/PCRep message. 203 5.1. RP Object Extension 205 The following flags are added into the RP Object: 207 o L (Label distribution bit - 1 bit): 208 0: This indicates that this is not a PCReq/PCRep message 209 for distributing labels crossing domains. 210 1: This indicates that this is a PCReq or PCRep message 211 for distributing labels crossing domains. 213 o C (LSP tunnel Creation bit - 1 bit): 214 0: This indicates that this is not a PCReq/PCRep message for 215 creating the segment of the LSP tunnel. 216 1: This indicates that this is a PCReq/PCRep message for 217 creating the segment of the LSP tunnel in the domain 218 before distributing labels to its previous domain. 220 An L bit is added in the flag bits field of the RP object to tell a 221 receiver of a PCReq/PCRep message that the message is for 222 distributing labels crossing domains for an inter-domain LSP. The 223 IANA request is referenced in Section below (Request Parameter Bit 224 Flags) of this document. 226 The C bit is added in the flag bits field of the RP object to tell 227 the receiver of a PCReq/PCRep message that the message is for 228 creating the segment of the LSP tunnel in a domain before 229 distributing labels from this domain to its previous domain. The 230 IANA request is referenced in Section below (Request Parameter Bit 231 Flags) of this document. 233 This L bit with the N bit defined in RFC6006 can indicate whether the 234 PCReq/PCRep message is for distributing labels for an MPLS TE P2P LSP 235 or an MPLS TE P2MP LSP. 237 o L = 1 and N = 0: This indicates that this is a PCReq/PCRep message 238 for distributing labels for a P2P LSP. 239 o L = 1 and N = 1: This indicates that this is a PCReq/PCRep message 240 for distributing labels for a P2MP LSP. 242 5.2. Label Object 244 The format of a label object body (Object-Type=2) is illustrated 245 below, which comprises a label and an optional node sub object. The 246 node sub object contains a boundary node IP address, from which the 247 label is allocated and distributed. 249 0 1 2 3 250 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 1 251 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 252 | Label | 253 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 254 | Node IPv4/IPv6 sub object (optional) | 255 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 257 The format of the node IPv4 address sub object (Type=1) is as 258 follows: 260 0 1 2 3 261 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 1 262 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 263 |L| Type(1) | Length (8) | Node IPv4 address | 264 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 265 | Node IPv4 address (cont) | Reserved | 266 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 268 The format of the node IPv6 address sub object (Type=2) is 269 illustrated below: 271 0 1 2 3 272 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 1 273 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 274 |L| Type(2) | Length (20) | Node IPv6 address | 275 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 276 | | 277 | Node IPv6 address (cont) | 278 | | 279 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 280 | Node IPv6 address (cont) | Reserved | 281 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 283 5.3. LSP Tunnel Object 285 The LSP tunnel object contains the information that may be used to 286 identify an LSP tunnel. An LSP tunnel may be a P2P or P2MP LSP 287 tunnel. It may be an IPv4 or IPv6 LPS tunnel. Thus there are four 288 types of LSP tunnels: 1) P2P LSP IPv4 tunnel, 2) P2P LSP IPv6 tunnel, 289 3) P2MP LSP IPv4 tunnel, and 4) P2MP LSP IPv6 tunnel. 291 The format of the P2P LSP IPv4/6 tunnel object body is as follows: 293 0 1 2 3 294 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 1 295 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 296 | P2P LSP Tunnel Egress IPv4/6 Address (4/16 bytes) | 297 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 298 | Reserved | Tunnel ID | 299 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 300 | Extended Tunnel ID (4/16 bytes) | 301 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 302 | Reserved | LSP ID | 303 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 304 | Controller ID (4/16 bytes) | 305 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 307 o P2P LSP Tunnel Egress IPv4/6 Address: 308 IPv4/6 address of the egress of the tunnel. 309 o Tunnel ID: 310 A 16-bit identifier that is constant over the life of the tunnel. 311 o Extended Tunnel ID: 312 A 4/16-byte identifier that is constant over the life of the tunnel. 313 o LSP ID: 314 A 16-bit identifier to allow resources sharing. 315 o Controller ID: 316 A 4/16-byte identifier for the controller responsible for the head 317 segment of the tunnel. 319 The format of the P2MP LSP IPv4/6 tunnel object body is as follows: 321 0 1 2 3 322 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 1 323 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 324 | P2MP ID | 325 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 326 | Reserved | Tunnel ID | 327 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 328 | Extended Tunnel ID (4/16 bytes) | 329 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 330 | Reserved | LSP ID | 331 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 332 | Controller ID (4/16 bytes) | 333 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 335 o P2MP ID: 336 A 32-bit number unique within the ingress of LSP tunnel. 337 o Tunnel ID: 338 A 16-bit identifier that is constant over the life of the tunnel. 339 o Extended Tunnel ID: 340 A 4/16-byte identifier that is constant over the life of the tunnel. 341 o LSP ID: 342 A 16-bit identifier to allow resources sharing. 343 o Controller ID: 344 A 16-byte identifier for the controller responsible for the head 345 segment of the tunnel. 347 5.4. Request Message Extension 349 Figure below illustrates the format of a request message with a 350 optional LSP tunnel object: 352 ::= 353 [] 354 355 ::=[] 356 ::= [] [] [] 357 [] [[]] [] 358 [] 359 [] 361 5.5. Reply Message Extension 363 Below is the format of a reply message with an optional Label object: 365 ::= 366 367 ::=[] 368 ::= 369 [] 370 [] 371 [] 372 ::=[] 373 ::= [][