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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 PCE Working Group H. Chen 3 Internet-Draft Huawei Technologies 4 Intended status: Standards Track M. Toy 5 Expires: March 15, 2018 Verizon 6 X. Liu 7 Jabil 8 L. Liu 9 Fujitsu 10 Z. Li 11 China Mobile 12 September 11, 2017 14 PCEP Link State Abstraction 15 draft-chen-pce-h-connect-access-03 17 Abstract 19 This document presents extensions to the Path Computation Element 20 Communication Protocol (PCEP) for a child PCE to abstract its domain 21 information to its parent for supporting a hierarchical PCE system. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at http://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on March 15, 2018. 40 Copyright Notice 42 Copyright (c) 2017 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (http://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 58 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 59 3. Conventions Used in This Document . . . . . . . . . . . . . . 3 60 4. Connections and Accesses . . . . . . . . . . . . . . . . . . . 4 61 4.1. Information on Inter-domain Link . . . . . . . . . . . . . 4 62 4.2. Information on ABR . . . . . . . . . . . . . . . . . . . . 5 63 4.3. Information on Access Point . . . . . . . . . . . . . . . 5 64 5. Extensions to PCEP . . . . . . . . . . . . . . . . . . . . . . 6 65 5.1. Messages for Abstract Information . . . . . . . . . . . . 6 66 5.2. Procedures . . . . . . . . . . . . . . . . . . . . . . . . 7 67 5.2.1. Child Procedures . . . . . . . . . . . . . . . . . . . 7 68 5.2.2. Parent Procedures . . . . . . . . . . . . . . . . . . 9 69 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 70 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 71 8. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 11 72 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 73 9.1. Normative References . . . . . . . . . . . . . . . . . . . 11 74 9.2. Informative References . . . . . . . . . . . . . . . . . . 11 75 Appendix A. Message Encoding . . . . . . . . . . . . . . . . . . 12 76 A.1. Extension to Existing Message . . . . . . . . . . . . . . 12 77 A.1.1. TLVs . . . . . . . . . . . . . . . . . . . . . . . . . 12 78 A.1.2. Sub-TLVs . . . . . . . . . . . . . . . . . . . . . . . 13 79 A.2. New Message . . . . . . . . . . . . . . . . . . . . . . . 14 80 A.2.1. CONNECTION and ACCESS Object . . . . . . . . . . . . . 15 82 1. Introduction 84 A hierarchical PCE architecture is described in RFC 6805, in which a 85 parent PCE maintains an abstract domain topology, which contains its 86 child domains (seen as vertices in the topology) and the connections 87 among them. 89 For a domain for which a child PCE is responsible, connections 90 attached to the domain may comprise inter-domain links and Area 91 Border Routers (ABRs). For a parent PCE to have the abstract domain 92 topology, each of its child PCEs needs to advertise its connections 93 to the parent PCE. 95 In addition to the connections attached to the domain, there may be 96 some access points in the domain, which are the addresses in the 97 domain to be accessible outside of the domain. For example, an 98 address of a server in the domain that provides a number of services 99 to users outside of the domain is an access point. 101 This document presents extensions to the Path Computation Element 102 Communication Protocol (PCEP) for a child PCE to advertise the 103 information about its connections and access points to its parent PCE 104 and for the parent PCE to build and maintain the abstract domain 105 topology based on the information. The extensions may reduce 106 configurations, thus simplify operations on a PCE system. 108 A child PCE is simply called a child and a parent PCE is called a 109 parent in the following sections. 111 2. Terminology 113 ABR: Area Border Router. Router used to connect two IGP areas 114 (Areas in OSPF or levels in IS-IS). 116 ASBR: Autonomous System (AS) Border Router. Router used to connect 117 together ASes via inter-AS links. 119 TED: Traffic Engineering Database. 121 This document uses terminology defined in [RFC5440]. 123 3. Conventions Used in This Document 125 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 126 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 127 document are to be interpreted as described in [RFC2119]. 129 4. Connections and Accesses 131 A connection is an inter-domain link between two domains in general. 132 An ABR is also a connection, which connects two special domains 133 called areas in a same Autonomous System (AS). 135 An access point in a domain is an address in the domain to be 136 accessible to the outside of the domain. An access point is simply 137 called an access. 139 4.1. Information on Inter-domain Link 141 An inter-domain link connects two domains in two different ASes. 142 Since there is no IGP running over an inter-domain link, we may not 143 obtain the information about the link generated by an IGP. We may 144 suppose that IP addresses are configured on inter-domain links. 146 For a point-to-point (P2P) link connecting two ABSRs A and B in two 147 different domains, from A's point of view, the following information 148 about the link may be obtained: 150 1) Link Type: P2P 151 2) Local IP address 152 3) Remote IP address 153 4) Traffic engineering metric 154 5) Maximum bandwidth 155 6) Maximum reservable bandwidth 156 7) Unreserved bandwidth 157 8) Administrative group 158 9) SRLG 160 We will have a link ID if it is configured; otherwise no link ID 161 (i.e., the Router ID of the neighbor) may be obtained since no IGP 162 adjacency over the link is formed. 164 For a broadcast link connecting multiple ASBRs in a number of 165 domains, on each of the ASBRs X, the same information about the link 166 as above may be obtained except for the followings: 168 a) Link Type: Multi-access, 169 b) Local IP address with mask length, and 170 c) No Remote IP address. 172 In other words, the information about the broadcast link obtained by 173 ASBR X comprises a), b), 4) to 9), but does not include any remote IP 174 address or link ID. We will have a link ID if it is configured; 175 otherwise no link ID (i.e., the interface address of the designated 176 router for the link) may be obtained since no IGP selects it. 178 A parent constructs an abstract AS domain topology after receiving 179 the information about each of the inter-domain links described above 180 from its children. 182 RFC 5392 and RFC 5316 describe the distributions of inter-domain 183 links in OSPF and IS-IS respectively. For each inter-domain link, 184 its neighboring AS number and neighboring ASBR Identity (TE Router 185 ID) need to be configured in IGP (OSPF or IS-IS). 187 In addition, an IGP adjacency between a network node running IGP and 188 a PCE running IGP as a component needs to be configured and fully 189 established if we want the PCE to obtain the inter-domain link 190 information from IGP. 192 These configurations and IGP adjacency establishment are not needed 193 if the extensions in this draft are used. 195 RFC 7752 (BGP-LS) describes the distributions of TE link state 196 information including inter-domain link state. A BGP peer between a 197 network node running BGP and a PCE running BGP as a component needs 198 to be configured and the peer relation must be established before the 199 PCE can obtain the inter-domain link information from BGP. However, 200 some networks may not run BGP. 202 4.2. Information on ABR 204 For an AS running IGP and containing multiple areas, an ABR connects 205 two or more areas. For each area connected to the ABR, the PCE as a 206 child responsible for the area sends its parent the information about 207 the ABR, which indicates the identifier (ID) of the ABR. 209 A parent has the information about each of its children, which 210 includes the domain such as the area for which the child is 211 responsible. The parent knows all the areas to which each ABR 212 connects after receiving the information on the ABR from each of its 213 children. 215 4.3. Information on Access Point 217 For an IP address in a domain to be accessible outside of the domain, 218 the PCE as a child responsible for the domain sends its parent the 219 information about the address. 221 The parent has all the access points (i.e., IP addresses) to be 222 accessible outside of all its children' domains after receiving the 223 information on the access points from each of its children. 225 5. Extensions to PCEP 227 This section focuses on procedures for abstracting domain information 228 after briefing messages containing the abstract information. 230 5.1. Messages for Abstract Information 232 A child abstracts its domain to its parent through sending its parent 233 a message containing the abstract information on the domain. After 234 the relation between the child and the parent is determined, the 235 parent has some information on the child, which includes the child's 236 ID and domain. The message does not need to contain this 237 information. It comprises the followings: 239 o For new or updated Connections and Accesses, 241 * Indication of Update Connections and Accesses 243 * Detail Information about Connections and Accesses 245 o For Connections and Accesses down, 247 * Indication of Withdraw Connections and Accesses 249 * ID Information about Connections and Accesses 251 For a P2P link from ASBR A to B and a broadcast link connecting to A, 252 the detail information on the links includes A's ID, the information 253 on the P2P link and the information on the broadcast link described 254 in Section 4. The ID information on the links includes A's ID, 1) to 255 3) for the P2P link and a) to b) for the broadcast link described in 256 Section 4. A link ID for a link is included if it is configured. 258 For an ABR X, the information on X includes X's ID and a flag 259 indicating that X is ABR. 261 For an Access X (address), the detail information on X includes X and 262 a cost associated with it. The ID information on X is X itself. 264 There are a few ways to encode the information above into a message. 265 For example, one way is to extend an existing Notification message 266 for including the information. Another way is to use a new message. 267 These are put in Appendix A for your reference. 269 5.2. Procedures 271 5.2.1. Child Procedures 273 5.2.1.1. New or Changed Connections and Accesses 275 After a child determines its parent, it sends the parent a message 276 containing the information about the connections (i.e., inter-domain 277 links and ABRs) from its domain to its adjacent domains and the 278 access points in its domain. 280 For any new or changed inter-domain links, ABRs and access points in 281 the domain for which a child is responsible, the child sends its 282 parent a message containing the information about these links, ABRs 283 and access points with indication of Update Connections and Accesses. 285 For example, for a new inter-domain P2P link from ASBR A in a child's 286 domain to ASBR B in another domain, the child sends its parent a 287 message containing an indication of Update Connections and Accesses, 288 A's ID, and the detail information on the link described in section 289 4.1. 291 For multiple new or changed inter-domain links from ASBR A, the child 292 sends its parent a message having an indication of Update Connections 293 and Accesses, and A's ID followed by the detail information about 294 each of the links. 296 In another example, for a new or changed inter-domain broadcast link 297 connected to ASBR X, an ABR Y and an access point 10.10.10.1/32 with 298 cost 10 in a child's domain, the child sends its parent a message 299 containing an indication of Update Connections and Accesses, and X's 300 ID followed by the detail information about the link attached to X 301 and the detail information about ABR Y, and the information on access 302 10.10.10.1/32 with cost 10. 304 For changes on the attributes (such as bandwidth) of an inter-domain 305 link, a threshold may be used to control the frequency of updates 306 that are sent from a child to its parent. At one extreme, the 307 threshold is set to let a child send its parent a update message for 308 any change on the attributes of an inter-domain link. At another 309 extreme, the threshold is set to make a child not to send its parent 310 any update message for any change on the attributes of an inter- 311 domain link. Typically, the threshold is set to allow a child to 312 send its parent a update message for a significant change on the 313 attributes of an inter-domain link. 315 5.2.1.2. Connections and Accesses Down 317 For any inter-domain links, ABRs and access points down in the domain 318 for which a child is responsible, the child sends its parent a 319 message containing the information about these links, ABRs and access 320 points with indication of Withdraw Connections and Accesses. 322 For example, for the inter-domain P2P link from ASBR A down, the 323 child sends its parent a message containing an indication of Withdraw 324 Connections and Accesses, and A's ID, which is followed by the ID 325 information about the link. 327 For multiple inter-domain links from ASBR A down, the child sends its 328 parent a message having an indication of Withdraw Connections and 329 Accesses, and A's ID, which is followed by the ID information about 330 each of the links. 332 5.2.1.3. Child and Parent in Same Organization 334 If a child and its parent are in a same organization, the child may 335 send its parent the information inside its domain. For a parent, 336 after all its children in its organization send their parent the 337 information in their domains, connections and access points, it has 338 in its TED the detail information inside each of its children's 339 domains and the connections among these domains. The parent can 340 compute a path crossing these domains directly and efficiently 341 without sending any path computation request to its children. 343 5.2.1.4. Child as a Parent 345 There are a few ways in which a child as a parent abstracts its 346 domain information to its parent. 348 One way is that the child sends its parent all its domain information 349 if the child and the parent are in a same organization. The 350 information includes the detail network topology inside each of the 351 child's domains, the inter-domain links connecting the domains that 352 the child's children are responsible and the inter-domain links 353 connecting these domains to other adjacent domains. 355 In another way, the child abstracts each of the domains that its 356 children are responsible as a cloud (or say abstract node) and these 357 clouds are connected by the inter-domain links attached to the 358 domains. The child sends its parent all the inter-domain links 359 attached to any of the domains. 361 In a third way, the child abstracts all its domains including the 362 domains for which its children are responsible as a cloud. This 363 abstraction is described below in details. 365 If a parent P1 is also a child of another parent P2, P1 as a child 366 sends its parent P2 a message containing the information about the 367 connections and access points. P1 as a parent has the connections 368 among its children's domains. But these connections are hidden from 369 its parent P2. P1 may have connections from its children's domains 370 to other domains. P1 as a child sends its parent P2 these 371 connections. 373 P1 as a parent has the access points in its children's domains to be 374 accessible outside of the domains. P1 as child may not send all of 375 these to its parent P2. It sends its parent some of these access 376 points according to some local policies. 378 From P2's point of view, its child P1 is responsible for one domain, 379 which has some connections to its adjacent domains and some access 380 points to be accessible. 382 5.2.2. Parent Procedures 384 5.2.2.1. Process Connections and Accesses 386 A parent stores into its TED the connections and accesses for each of 387 its children according to the messages containing connections and 388 accesses received. For a message containing Update Connections and 389 Accesses, it updates the connections and accesses in the TED 390 accordingly. For a message containing Withdraw Connections and 391 Accesses, it removes the connections and accesses from the TED. 393 After receiving the messages for connections and accesses from its 394 children, the parent builds and maintains the TED for the topology of 395 its children's domains, in which each of the domains is seen as a 396 cloud or an abstract node. The information inside each of the 397 domains is hidden from the parent. There are connections among the 398 domains and the access points in the domains to be accessible in the 399 topology. 401 For a new P2P link from node A to B with no link ID configured, when 402 receiving a message containing the link from a child, the parent 403 stores the link from A into its TED, where A is attached to the 404 child's domain as a cloud. It finds the link's remote end B using 405 the remote IP address of the link. After finding B, it associates 406 the link attached to A with B and the link attached to B with A. This 407 creates a bidirectional connection between A and B. 409 For a new P2P link from node A to B with link ID configured, when 410 receiving a message containing the link, the parent stores the link 411 from A into its TED. It finds the link's remote end B using the link 412 ID (i.e., B's ID). 414 For a new broadcast link connecting multiple nodes with no link ID 415 configured, when the parent receives a message containing the link 416 attached to node X, it stores the link from X into its TED. It finds 417 the link's remote end P using the link's local IP address with 418 network mask. P is a Pseudo node identified by the local IP address 419 of the designated node selected from the nodes connected to the link. 420 After finding P, it associates the link attached to X with P and the 421 link connected to P with X. If P is not found, a new Pseudo node P is 422 created. The parent associates the link attached to X with P and the 423 link attached to P with X. This creates a bidirectional connection 424 between X and P. 426 The first node and second node from which the parent receives a 427 message containing the link is selected as the designed node and 428 backup designed node respectively. After the designed node is down, 429 the backup designed node becomes the designed node and the node other 430 than the designed node with the largest local IP address connecting 431 to the link is selected as the backup designed node. 433 When the old designed node is down and the backup designed node 434 becomes the new designed node, the parent updates its TED through 435 removing the link between each of nodes X and old P (the Pseudo node 436 corresponding to the old designed node) and adding a link between 437 each of nodes X (still connecting to the broadcast link) and new P 438 (the Pseudo node corresponding to the new designed node). 440 5.2.2.2. Detail Topology in a Domain 442 If a parent is in a same organization as its child, it stores into 443 its TED the detail information inside the child's domain when 444 receiving a message containing the information from the child; 445 otherwise, it discards the information and issues a warning 446 indicating that the information is sent to a wrong place. 448 6. Security Considerations 450 The mechanism described in this document does not raise any new 451 security issues for the PCEP protocols. 453 7. IANA Considerations 455 This section specifies requests for IANA allocation. 457 8. Acknowledgement 459 The authors would like to thank Jescia Chen, Adrian Farrel, and Eric 460 Wu for their valuable comments on this draft. 462 9. References 464 9.1. Normative References 466 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 467 Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ 468 RFC2119, March 1997, 469 . 471 [RFC6805] King, D., Ed. and A. Farrel, Ed., "The Application of the 472 Path Computation Element Architecture to the Determination 473 of a Sequence of Domains in MPLS and GMPLS", RFC 6805, 474 DOI 10.17487/RFC6805, November 2012, 475 . 477 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 478 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 479 DOI 10.17487/RFC5440, March 2009, 480 . 482 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 483 (TE) Extensions to OSPF Version 2", RFC 3630, 484 DOI 10.17487/RFC3630, September 2003, 485 . 487 9.2. Informative References 489 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 490 Engineering", RFC 5305, DOI 10.17487/RFC5305, 491 October 2008, . 493 [RFC5392] Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in 494 Support of Inter-Autonomous System (AS) MPLS and GMPLS 495 Traffic Engineering", RFC 5392, DOI 10.17487/RFC5392, 496 January 2009, . 498 [RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in 499 Support of Inter-Autonomous System (AS) MPLS and GMPLS 500 Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316, 501 December 2008, . 503 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and 504 S. Ray, "North-Bound Distribution of Link-State and 505 Traffic Engineering (TE) Information Using BGP", RFC 7752, 506 DOI 10.17487/RFC7752, March 2016, 507 . 509 Appendix A. Message Encoding 511 A.1. Extension to Existing Message 513 An existing Notification message may be extended to advertise the 514 information about connections and access points. The following new 515 Notification-type (NT) and Notification-value (NV) of a NOTIFICATION 516 object in the message are defined: 518 o NT=8 (TBD): Connections and Accesses 520 * NV=1: Update Connections and Accesses. A NT=8 and NV=1 521 indicates that the child sends its parent updates on the 522 information about Connections and Accesses, and TLVs containing 523 the information are in the object. 525 * NV=2: Withdraw Connections and Accesses. A NT=8 and NV=2 526 indicates that the child asks its parent to remove Connections 527 and Accesses indicated by TLVs in the object. 529 A.1.1. TLVs 531 Four TLVs are defined for connections and accesses. They are Inter- 532 Domain link TLV, Router-ID TLV, Access IPv4/IPv6 Prefix TLV. 534 The format of the Inter-Domain link TLV is illustrated below. 536 0 1 2 3 537 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 1 538 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 539 | Type (tTBD1) | Length | 540 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 541 | Inter-Domain Link Sub-TLVs | 542 ~ ~ 543 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 545 An Inter-Domain link TLV describes a single inter-domain link. It 546 comprises a number of inter-domain link sub-TLVs for the information 547 described in section 4, which are the sub-TLVs defined in RFC 3630 or 548 their equivalents except for the local IP address with mask length 549 defined below. 551 The format of the Router-ID TLV is shown below. Undefined flags MUST 552 be set to zero. The ID indicates the ID of a router. For a router 553 running OSPF, the ID may be the 32-bit OSPF router ID of the router. 554 For a router running IS-IS, the ID may be the 48-bit IS-IS router ID 555 of the router. For a router not running OSPF or IS-IS, the ID may be 556 the 32-bit ID of the router configured. 558 0 1 2 3 559 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 1 560 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 561 | Type (tTBD2) | Length | 562 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 563 |B|E|I| Flags | | 564 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + 565 | 32-bit/48-bit ID ~ 566 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 567 Flag B: Set to 1 indicating ABR (B is for Border) 568 Flag E: Set to 1 indicating ASBR (E is for External) 569 Flag I: Set to 1 indicating ID of local router (I is for ID) 571 The format of the Access IPv4/IPv6 Prefix TLV is shown as follows. 572 The cost is the metric to the prefix. The Prefix Length indicates 573 the length of the prefix. The IPv4/IPv6 Prefix indicates an access 574 IPv4/IPv6 address prefix. 576 0 1 2 3 577 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 1 578 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 579 | Type (tTBD3/tTDB4) | Length | 580 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 581 | cost | 582 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 583 | Prefix Length | IPv4/IPv6 Prefix (variable) ~ 584 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 586 A.1.2. Sub-TLVs 588 The format of the Sub-TLV for a local IPv4/IPv6 address with mask 589 length is shown as follows. 591 0 1 2 3 592 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 1 593 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 594 | Type (stTBD1/stTBD2) | Length | 595 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 596 | IPv4/IPv6 Address ~ 597 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 598 | Mask Length | 599 +-+-+-+-+-+-+-+-+ 601 The IPv4/IPv6 Address indicates the local IPv4/IPv6 address of a 602 link. The Mask Length indicates the length of the IPv4/IPv6 address 603 mask. 605 A.2. New Message 607 A new message may be defined to advertise the connections and 608 accesses from a child to its parent. The format of the message 609 containing Connections and Access (AC for short) is as follows: 611 ::= 612 [] 613 where: 614 ::= [] 615 ::= [ | ] 616 ::= [] 618 Where the value of the Message-Type in the Common Header indicates 619 the new message type. The exact value is to be assigned by IANA. A 620 new RP (NRP) object will be defined, which follows the Common Header. 622 A new flag W (Withdraw) in the NRP object is defined to indicate 623 whether the connections and access are withdrawn. When flag W is set 624 to one, the parent removes the connections and accesses contained in 625 the message after receiving it. When flag W is set to zero, the 626 parent adds/updates the connections and accesses in the message after 627 receiving it. 629 An alternative to flag W in the NRP object is a similar flag in each 630 CONNECTION and ACCESS object such as using one bit in Res flags for 631 flag W. For example, when the flag is set to one in the object, the 632 parent removes the connections and accesses in the object after 633 receiving it. When the flag is set to zero in the object, the parent 634 adds/updates the connections and accesses in the object after 635 receiving it. 637 In another option, one byte in a CONNECTION and ACCESS Object is 638 defined as flags field and one bit is used as flag W. The other 639 undefined bits in the flags field MUST be set to zero. 641 The objects in the new message are defined below. 643 A.2.1. CONNECTION and ACCESS Object 645 A new object, called CONNECTION and ACCESS Object (CA for short), is 646 defined. It has Object-Class ocTBD1. Four Object-Types are defined 647 under CA object: 649 o CA Inter-Domain Link: CA Object-Type is 1. 651 o CA ABR: CA Object-Type is 2. 653 o CA Access IPv4 Prefix: CA Object-Type is 3. 655 o CA Access IPv6 Prefix: CA Object-Type is 4. 657 Each of these objects are described below. 659 The format of Inter-Domain Link object body is as follows: 661 Object-Class = ocTBD1 (Connection and Access) 662 Object-Type = 1 (CA Inter-Domain Link) 663 0 1 2 3 664 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 1 665 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 666 |W| Flags | Router-ID TLV | 667 +-+-+-+-+-+-+-+-+ + 668 ~ ~ 669 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 670 | Inter-Domain Link TLVs | 671 ~ ~ 672 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 674 The Router-ID TLV indicates an ASBR in the domain, which is a local 675 end of inter-domain links. Each of the Inter-Domain Link TLVs 676 describes an inter-domain link and comprises a number of inter-domain 677 link Sub-TLVs. Flag W=1 indicates withdraw the links. W=0 indicates 678 new or changed links. 680 The format of ABR object body is illustrated below: 682 Object-Class = ocTBD1 (Connection and Access) 683 Object-Type = 2 (CA ABR) 684 0 1 2 3 685 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 1 686 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 687 |W| Flags | Router-ID TLVs | 688 +-+-+-+-+-+-+-+-+ + 689 ~ ~ 690 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 692 Each of the Router-ID TLVs indicates an ABR in the domain. Flag W=1 693 indicates withdraw the ABRs. W=0 indicates new ABRs. 695 The format of Access IPv4/IPv6 Prefix object body is as follows: 697 Object-Class = ocTBD1 (Connection and Access) 698 Object-Type = 3/4 (CA Access IPv4/IPv6 Prefix) 699 0 1 2 3 700 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 1 701 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 702 |W| Flags | Access IPv4/IPv6 Prefix TLVs | 703 +-+-+-+-+-+-+-+-+ + 704 ~ ~ 705 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 707 Each of the Access IPv4/IPv6 Prefix TLVs describes an access IPv4/ 708 IPv6 address prefix in the domain, which is accessible to outside of 709 the domain. Flag W=1 indicates withdraw the address prefixes. W=0 710 indicates new address prefixes. 712 The TLVs in the objects are the same as those described above. 714 Authors' Addresses 716 Huaimo Chen 717 Huawei Technologies 718 Boston, MA, 719 USA 721 EMail: Huaimo.chen@huawei.com 722 Mehmet Toy 723 Verizon 724 USA 726 EMail: mehmet.toy@verizon.com 728 Xufeng Liu 729 Jabil 730 McLean, VA 731 USA 733 EMail: Xufeng_Liu@jabil.com 735 Lei Liu 736 Fujitsu 737 USA 739 EMail: lliu@us.fujitsu.com 741 Zhenqiang Li 742 China Mobile 743 No.32 Xuanwumenxi Ave., Xicheng District 744 Beijing 100032 745 P.R. China 747 EMail: li_zhenqiang@hotmail.com