idnits 2.17.1 draft-ietf-i2rs-yang-l2-network-topology-02.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 : ---------------------------------------------------------------------------- ** There are 5 instances of too long lines in the document, the longest one being 108 characters in excess of 72. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (December 22, 2015) is 3041 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) == Unused Reference: 'I-D.amante-i2rs-topology-use-cases' is defined on line 862, but no explicit reference was found in the text == Unused Reference: 'I-D.medved-i2rs-topology-requirements' is defined on line 867, but no explicit reference was found in the text == Outdated reference: A later version (-20) exists of draft-ietf-i2rs-yang-network-topo-02 == Outdated reference: A later version (-14) exists of draft-ietf-netmod-rfc6020bis-09 Summary: 1 error (**), 0 flaws (~~), 5 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group J. Dong 3 Internet-Draft X. Wei 4 Intended status: Standards Track Huawei Technologies 5 Expires: June 24, 2016 December 22, 2015 7 A YANG Data Model for Layer-2 Network Topologies 8 draft-ietf-i2rs-yang-l2-network-topology-02 10 Abstract 12 This document defines a YANG data model for Layer 2 network 13 topologies. 15 Requirements Language 17 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 18 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 19 document are to be interpreted as described in RFC 2119 [RFC2119]. 21 Status of This Memo 23 This Internet-Draft is submitted in full conformance with the 24 provisions of BCP 78 and BCP 79. 26 Internet-Drafts are working documents of the Internet Engineering 27 Task Force (IETF). Note that other groups may also distribute 28 working documents as Internet-Drafts. The list of current Internet- 29 Drafts is at http://datatracker.ietf.org/drafts/current/. 31 Internet-Drafts are draft documents valid for a maximum of six months 32 and may be updated, replaced, or obsoleted by other documents at any 33 time. It is inappropriate to use Internet-Drafts as reference 34 material or to cite them other than as "work in progress." 36 This Internet-Draft will expire on June 24, 2016. 38 Copyright Notice 40 Copyright (c) 2015 IETF Trust and the persons identified as the 41 document authors. All rights reserved. 43 This document is subject to BCP 78 and the IETF Trust's Legal 44 Provisions Relating to IETF Documents 45 (http://trustee.ietf.org/license-info) in effect on the date of 46 publication of this document. Please review these documents 47 carefully, as they describe your rights and restrictions with respect 48 to this document. Code Components extracted from this document must 49 include Simplified BSD License text as described in Section 4.e of 50 the Trust Legal Provisions and are provided without warranty as 51 described in the Simplified BSD License. 53 Table of Contents 55 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 56 2. Layer 2 Topology Model . . . . . . . . . . . . . . . . . . . 2 57 3. Layer-2 Topology Yang Module . . . . . . . . . . . . . . . . 6 58 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 59 5. Security Considerations . . . . . . . . . . . . . . . . . . . 18 60 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 18 61 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 62 7.1. Normative References . . . . . . . . . . . . . . . . . . 18 63 7.2. Informative References . . . . . . . . . . . . . . . . . 19 64 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19 66 1. Introduction 68 [I-D.ietf-i2rs-yang-network-topo] defines the Yang [RFC6020] 69 [RFC6991] [I-D.ietf-netmod-rfc6020bis]data models of the abstract 70 (generic) network and network topology. Such models can be augmented 71 with technology-specific details to build more specific topology 72 models. 74 This document defines the Yang data model for Layer 2 network 75 topologies by augmenting the generic network and network topology 76 data models with L2 specific topology attributes. 78 2. Layer 2 Topology Model 80 The Layer 2 network topology model is designed to be generic and 81 applicable to Layer 2 networks built with different L2 technologies. 83 The Layer 2 topology model applies the generic network and network 84 topology models to Layer 2 network topologies, and augments the 85 generic models with information specific in Layer 2 networks. The 86 relationship between the Layer 2 topology model and the generic 87 network and network topology model is shown in the figure below: 89 +---------------------+ 90 | ietf-network | 91 +----------^----------+ 92 | 93 | 94 +---------------------+ 95 |ietf-network-topology| 96 +----------^----------+ 97 | 98 | 99 +----------^----------+ 100 | ietf-l2-topology | 101 +---------------------+ 102 Figure 1. L2-topology model structure 104 In order to represent a Layer 2 network topology, the generic network 105 and topology models are augmented with Layer-2 specific information, 106 such as the identifiers, descriptions, attributes and states of the 107 Layer-2 networks, nodes, links and termination points. Some of the 108 information may be collected via Link Layer Discovery Protocl (LLDP) 109 or other Layer-2 protocols, and some of them may be locally 110 configured. 112 The structure of "ietf-l2-topology" data model is depicted in the 113 following diagram. Brackets enclose list keys, "rw" means 114 configuration data, "ro" means operational state data, "?" designates 115 optional nodes, "*" designates nodes that can have multiple 116 instances. 118 module: ietf-l2-topology 119 augment /nw:networks/nw:network/nw:network-types: 120 +--rw l2-network! 121 augment /nw:networks/nw:network: 122 +--rw l2-network-attributes 123 +--rw name? string 124 +--rw flag* flag-type 125 augment /nw:networks/nw:network/nw:node: 126 +--rw l2-node-attributes 127 +--rw name? string 128 +--rw description? string 129 +--rw management-address* inet:ip-address 130 +--rw management-vid? vlan {VLAN}? 131 +--rw nick-name* trill-nickname {TRILL}? 132 +--rw flag* flag-type 133 augment /nw:networks/nw:network/nt:link: 134 +--rw l2-link-attributes 135 +--rw name? string 136 +--rw flag* flag-type 137 +--rw rate? decimal64 138 +--rw delay? uint32 139 +--rw srlg* uint32 140 augment /nw:networks/nw:network/nw:node/nt:termination-point: 141 +--rw l2-termination-point-attributes 142 +--rw description? string 143 +--rw maximum-frame-size? uint32 144 +--rw (l2-termination-point-type)? 145 | +--:(ethernet) 146 | | +--rw mac-address? yang:mac-address 147 | | +--rw eth-encapsulation? identityref 148 | | +--rw port-vlan-id? vlan {VLAN}? 149 | | +--rw vlan-id-name* [vlan-id] {VLAN}? 150 | | +--rw vlan-id vlan 151 | | +--rw vlan-name? string 152 | +--:(legacy) 153 | +--rw encapsulation? identityref 154 +--ro tp-state? enumeration 155 notifications: 156 +---n l2-node-event 157 | +--ro event-type? l2-network-event-type 158 | +--ro network-ref? -> /nw:networks/network/network-id 159 | +--ro node-ref? -> /nw:networks/network[nw:network-id = current()/../network-ref]/node/node-id 160 | +--ro l2-network! 161 | +--ro l2-node-attributes 162 | +--ro name? string 163 | +--ro description? string 164 | +--ro management-address* inet:ip-address 165 | +--ro management-vid? vlan {VLAN}? 166 | +--ro nick-name* trill-nickname {TRILL}? 167 | +--ro flag* flag-type 168 +---n l2-link-event 169 | +--ro event-type? l2-network-event-type 170 | +--ro network-ref? -> /nw:networks/network/network-id 171 | +--ro link-ref? -> /nw:networks/network[nw:network-id = current()/../network-ref]/nt:link/link-id 172 | +--ro l2-network! 173 | +--ro l2-link-attributes 174 | +--ro name? string 175 | +--ro flag* flag-type 176 | +--ro rate? decimal64 177 | +--ro delay? uint32 178 | +--ro srlg* uint32 179 +---n l2-termination-point-event 180 +--ro event-type? l2-network-event-type 181 +--ro network-ref? -> /nw:networks/network/network-id 182 +--ro node-ref? -> /nw:networks/network[nw:network-id = current()/../network-ref]/node/node-id 183 +--ro tp-ref? -> /nw:networks/network[nw:network-id = current()/../network-ref]/node[nw:node-id = current()/../node-ref]/nt:termination-point/tp-id 184 +--ro l2-network! 185 +--ro l2-termination-point-attributes 186 +--ro description? string 187 +--ro maximum-frame-size? uint32 188 +--ro (l2-termination-point-type)? 189 | +--:(ethernet) 190 | | +--ro mac-address? yang:mac-address 191 | | +--ro eth-encapsulation? identityref 192 | | +--ro port-vlan-id? vlan {VLAN}? 193 | | +--ro vlan-id-name* [vlan-id] {VLAN}? 194 | | +--ro vlan-id vlan 195 | | +--ro vlan-name? string 196 | +--:(legacy) 197 | +--ro encapsulation? identityref 198 +--ro tp-state? enumeration 200 The L2-topology module augments the generic ietf-network and ietf- 201 network-topology modules as follows: 203 o A new network type "l2-network-type" is introduced. This is 204 represented by a container object, and is inserted under the 205 "network-types" container of the generic ietf-network module in 206 [I-D.ietf-i2rs-yang-network-topo]. 208 o Additional network attributes are introduced in a grouping "l2- 209 network-attributes", which augments the "network" list of the 210 ietf-network module. The attributes include Layer-2 network name 211 and a set of flags. Each type of flag is represented by a 212 separate identity. 214 o Additional data objects for Layer-2 nodes are introduced by 215 augmenting the "node" list of the generic ietf-network module. 216 New objects include Layer-2 node identifier, description, 217 management address, and a set of flags. 219 o Additional data objects for Layer-2 termination points are 220 introduced by augmenting the "termination-point" list of the ietf- 221 network-topology module defined in 222 [I-D.ietf-i2rs-yang-network-topo]. New objects include Layer-2 223 termination point descriptions, Layer-2 termination point type 224 specific attributes and Layer-2 termination point states. 226 o Links in the ietf-network-topology module are augmented as well 227 with a set of Layer-2 parameters, allowing to associate a link 228 with a name, a set of Layer-2 link attributes and flags. 230 o The optional L2 technology specific attributes are introduced in 231 this module as Layer-2 features. 233 3. Layer-2 Topology Yang Module 235 file "ietf-l2-topology@2015-12-22.yang" 236 module ietf-l2-topology { 237 yang-version 1.1; 238 namespace "urn:ietf:params:xml:ns:yang:ietf-l2-topology"; 239 prefix "l2t"; 241 import ietf-network { 242 prefix "nw"; 243 } 245 import ietf-network-topology { 246 prefix "nt"; 247 } 249 import ietf-inet-types { 250 prefix "inet"; 251 } 253 import ietf-yang-types { 254 prefix "yang"; 255 } 257 organization 258 "IETF I2RS (Interface to the Routing System) Working Group"; 259 contact 260 "WG Web: 261 WG List: 262 WG Chair: Susan Hares 263 265 WG Chair: Jeffrey Haas 266 268 Editor: Jie Dong 269 271 Editor: Xiugang Wei 272 "; 274 description 275 "This module defines a basic model for 276 the layer-2 topology of a network"; 278 revision "2015-12-22" { 279 description "Initial revision"; 280 reference "draft-ietf-i2rs-l2-network-topology-02"; 282 } 284 /* 285 * Typedefs 286 */ 288 typedef vlan { 289 type uint16 { 290 range "0..4095"; 291 } 292 description "VLAN ID"; 293 } 295 typedef trill-nickname { 296 type uint16; 297 description "TRILL Nickname"; 298 } 300 typedef flag-type { 301 type identityref { 302 base "flag-identity"; 303 } 304 description "Base type for flags"; 305 } 307 typedef l2-network-event-type { 308 type enumeration { 309 enum "add" { 310 value 0; 311 description "An L2 node or link or termination-point 312 has been added"; 313 } 314 enum "remove" { 315 value 1; 316 description "An L2 node or link or termination-point 317 has been removed"; 318 } 319 enum "update" { 320 value 2; 321 description "An L2 node or link or termination-point 322 has been updated"; 323 } 324 } 325 description "l2 network event type for notifications"; 326 } // l2-topology-event-type 327 /* 328 * Features 329 */ 331 feature VLAN { 332 description 333 "Indicates that the system supports the 334 vlan functions"; 335 } 337 feature QinQ { 338 description 339 "Indicates that the system supports the 340 qinq functions"; 341 } 343 feature PBB { 344 description 345 "Indicates that the device supports the 346 provider-backbone-bridging functions"; 347 } 349 feature VPLS { 350 description 351 "Indicates that the device supports the 352 VPLS functions"; 353 reference "RFC 4761, RFC 4762"; 354 } 356 feature TRILL { 357 description 358 "Indicates that the device supports the 359 TRILL functions"; 360 reference "RFC 6325"; 361 } 363 feature VXLAN { 364 description 365 "Indicates that the device supports the 366 VXLAN functions"; 367 reference "RFC 7348"; 368 } 370 /* 371 * Identities 372 */ 373 identity flag-identity { 374 description "Base type for flags"; 375 } 377 identity encapsulation-type { 378 description 379 "Base identity from which specific encapsulation 380 types are derived."; 381 } 383 identity eth-encapsulation-type { 384 base encapsulation-type; 385 description 386 "Base identity from which specific ethernet 387 encapsulation types are derived."; 389 } 391 identity ethernet { 392 base eth-encapsulation-type; 393 description 394 "native ethernet encapsulation"; 395 } 397 identity vlan { 398 base eth-encapsulation-type; 399 description 400 "vlan encapsulation"; 401 } 403 identity qinq { 404 base eth-encapsulation-type; 405 description 406 "qinq encapsulation"; 407 } 409 identity pbb { 410 base eth-encapsulation-type; 411 description 412 "pbb encapsulation"; 413 } 415 identity trill { 416 base eth-encapsulation-type; 417 description 418 "trill encapsulation"; 419 } 420 identity vpls { 421 base eth-encapsulation-type; 422 description 423 "vpls encapsulation"; 424 } 426 identity vxlan { 427 base eth-encapsulation-type; 428 description 429 "vxlan encapsulation"; 430 } 432 identity frame-relay { 433 base encapsulation-type; 434 description 435 "Frame Relay encapsulation"; 436 } 438 identity ppp { 439 base encapsulation-type; 440 description 441 "PPP encapsulation"; 442 } 444 identity hdlc { 445 base encapsulation-type; 446 description 447 "HDLC encapsulation"; 448 } 450 identity atm { 451 base encapsulation-type; 452 description 453 "Base identity from which specific ATM 454 encapsulation types are derived."; 456 } 458 identity pwe3 { 459 base encapsulation-type; 460 description 461 "Base identity from which specific pw 462 encapsulation types are derived."; 463 } 465 /* 466 * Groupings 467 */ 469 grouping l2-network-type { 470 description "Identify the topology type to be L2."; 471 container l2-network { 472 presence "indicates L2 Network"; 473 description 474 "The presence of the container node indicates 475 L2 Topology"; 476 } 477 } 479 grouping l2-network-attributes { 480 description "L2 Topology scope attributes"; 481 container l2-network-attributes { 482 description "Containing L2 network attributes"; 483 leaf name { 484 type string; 485 description "Name of the L2 network"; 486 } 488 leaf-list flag { 489 type flag-type; 490 description "L2 network flags"; 491 } 492 } 493 } 495 grouping l2-node-attributes { 496 description "L2 node attributes"; 497 container l2-node-attributes { 498 description "Containing L2 node attributes"; 499 leaf name { 500 type string; 501 description "Node name"; 502 } 503 leaf description { 504 type string; 505 description "Node description"; 506 } 507 leaf-list management-address { 508 type inet:ip-address; 509 description "System management address"; 510 } 511 leaf management-vid { 512 if-feature VLAN; 513 type vlan; 514 description "System management VID"; 515 } 516 leaf-list nick-name { 517 if-feature TRILL; 518 type trill-nickname; 519 description "Nickname of the RBridge"; 520 } 521 leaf-list flag { 522 type flag-type; 523 description "Node operational flags"; 524 } 525 } 526 } // grouping l2-node-attributes 528 grouping l2-link-attributes { 529 description "L2 link attributes"; 530 container l2-link-attributes { 531 description "Containing L2 link attributes"; 532 leaf name { 533 type string; 534 description "Link name"; 535 } 536 leaf-list flag { 537 type flag-type; 538 description "Link flags"; 539 } 540 leaf rate { 541 type decimal64 { 542 fraction-digits 2; 543 } 544 description "Link rate"; 546 } 547 leaf delay { 548 type uint32; 549 description "Link delay in microseconds"; 550 } 551 leaf-list srlg { 552 type uint32; 553 description 554 "List of Shared Risk Link Groups 555 this link belongs to."; 556 } 557 } 558 } // grouping l2-link-attributes 560 grouping l2-termination-point-attributes { 561 description "L2 termination point attributes"; 562 container l2-termination-point-attributes { 563 description "Containing L2 TP attributes"; 564 leaf description { 565 type string; 566 description "Port description"; 567 } 569 leaf maximum-frame-size { 570 type uint32; 571 description "Maximum frame size"; 572 } 574 choice l2-termination-point-type { 575 description 576 "Indicates termination-point type 577 specific attributes"; 578 case ethernet { 579 leaf mac-address { 580 type yang:mac-address; 581 description "Interface MAC address"; 582 } 584 leaf eth-encapsulation { 585 type identityref { 586 base eth-encapsulation-type; 587 } 588 description 589 "Encapsulation type of this 590 ternimation point."; 591 } 593 leaf port-vlan-id { 594 if-feature VLAN; 595 type vlan; 596 description "Port VLAN ID"; 597 } 599 list vlan-id-name { 600 if-feature VLAN; 601 key "vlan-id"; 602 description "Interface configured VLANs"; 603 leaf vlan-id { 604 type vlan; 605 description "VLAN ID"; 606 } 607 leaf vlan-name { 608 type string; 609 description "VLAN Name"; 611 } 612 } 613 } //case ethernet 615 case legacy { 616 leaf encapsulation { 617 type identityref { 618 base encapsulation-type; 619 } 620 description 621 "Encapsulation type of this termination point."; 622 } 623 } //case legacy 625 } //choice termination-point-type 627 leaf tp-state { 628 type enumeration { 629 enum in-use { 630 value 0; 631 description 632 "the termination point is in forwarding state"; 633 } 634 enum blocking { 635 value 1; 636 description 637 "the termination point is in blocking state"; 638 } 639 enum down { 640 value 2; 641 description 642 "the termination point is in down state"; 643 } 644 enum others { 645 value 3; 646 description 647 "the termination point is in other state"; 648 } 649 } 650 config false; 651 description "State of the termination point"; 652 } 653 } 654 } // grouping l2-termination-point-attributes 656 /*** grouping of network/node/link/tp leaf-refs ***/ 658 grouping network-ref { 659 description 660 "Grouping for an absolute reference to a network topology 661 instance."; 662 leaf network-ref { 663 type leafref { 664 path "/nw:networks/nw:network/nw:network-id"; 665 } 666 description 667 "An absolute reference to a network topology instance."; 668 } 669 } 671 grouping link-ref { 672 description 673 "Grouping for an absolute reference to a link instance."; 674 uses network-ref; 675 leaf link-ref { 676 type leafref { 677 path "/nw:networks/nw:network" 678 +"[nw:network-id = current()/../network-ref]" 679 +"/nt:link/nt:link-id"; 680 } 681 description 682 "An absolute reference to a link instance."; 683 } 684 } 686 grouping node-ref { 687 description 688 "Grouping for an absolute reference to a node instance."; 689 uses network-ref; 690 leaf node-ref { 691 type leafref { 692 path "/nw:networks/nw:network" 693 +"[nw:network-id = current()/../network-ref]" 694 +"/nw:node/nw:node-id"; 695 } 696 description 697 "An absolute reference to a node instance."; 698 } 699 } 701 grouping tp-ref { 702 description 703 "Grouping for an absolute reference to a termination point."; 704 uses node-ref; 705 leaf tp-ref { 706 type leafref { 707 path "/nw:networks/nw:network" 708 +"[nw:network-id = current()/../network-ref]" 709 +"/nw:node[nw:node-id = current()/../node-ref]" 710 +"/nt:termination-point/nt:tp-id"; 711 } 712 description 713 "Grouping for an absolute reference to a TP."; 714 } 715 } 717 /* 718 * Data nodes 719 */ 721 augment "/nw:networks/nw:network/nw:network-types" { 722 description 723 "Introduce new network type for L2 topology"; 724 uses l2-network-type; 725 } 727 augment "/nw:networks/nw:network" { 728 when "/nw:networks/nw:network/nw:network-types/l2-network" { 729 description 730 "Augmentation parameters apply only for networks 731 with L2 topology"; 732 } 733 description 734 "Configuration parameters for the L2 network 735 as a whole"; 736 uses l2-network-attributes; 737 } 739 augment "/nw:networks/nw:network/nw:node" { 740 when "/nw:networks/nw:network/nw:network-types/l2-network" { 741 description 742 "Augmentation parameters apply only for networks 743 with L2 topology"; 744 } 745 description 746 "Configuration parameters for L2 at the node 747 level"; 748 uses l2-node-attributes; 749 } 751 augment "/nw:networks/nw:network/nt:link" { 752 when "/nw:networks/nw:network/nw:network-types/l2-network" { 753 description 754 "Augmentation parameters apply only for networks 755 with L2 topology"; 756 } 757 description "Augment L2 topology link information"; 758 uses l2-link-attributes; 759 } 761 augment "/nw:networks/nw:network/nw:node/nt:termination-point" { 762 when "/nw:networks/nw:network/nw:network-types/l2-network" { 763 description 764 "Augmentation parameters apply only for networks 765 with L2 topology"; 766 } 767 description 768 "Augment L2 topology termination point configuration"; 769 uses l2-termination-point-attributes; 770 } 772 /* 773 * Notifications 774 */ 776 notification l2-node-event { 777 description "Notification event for L2 node"; 778 leaf event-type { 779 type l2-network-event-type; 780 description "Event type"; 781 } 782 uses node-ref; 783 uses l2-network-type; 784 uses l2-node-attributes; 785 } 787 notification l2-link-event { 788 description "Notification event for L2 link"; 789 leaf event-type { 790 type l2-network-event-type; 791 description "Event type"; 792 } 793 uses link-ref; 794 uses l2-network-type; 795 uses l2-link-attributes; 796 } 798 notification l2-termination-point-event { 799 description "Notification event for L2 termination point"; 800 leaf event-type { 801 type l2-network-event-type; 802 description "Event type"; 803 } 804 uses tp-ref; 805 uses l2-network-type; 806 uses l2-termination-point-attributes; 807 } 809 } // module l2-topology 810 812 4. IANA Considerations 814 This document makes no request of IANA. 816 Note to RFC Editor: this section may be removed on publication as an 817 RFC. 819 5. Security Considerations 821 The transport protocol used for sending the topology data MUST 822 support authentication and SHOULD support encryption. The data-model 823 by itself does not create any security implications. 825 6. Acknowledgements 827 The authors would like to acknowledge the comments and suggestions 828 received from Susan Hares, Alia Atlas, Juergen Schoenwaelder, Mach 829 Chen, Alexander Clemm and Sriganesh Kini. 831 7. References 833 7.1. Normative References 835 [I-D.ietf-i2rs-yang-network-topo] 836 Clemm, A., Medved, J., Varga, R., Tkacik, T., Bahadur, N., 837 and H. Ananthakrishnan, "A Data Model for Network 838 Topologies", draft-ietf-i2rs-yang-network-topo-02 (work in 839 progress), December 2015. 841 [I-D.ietf-netmod-rfc6020bis] 842 Bjorklund, M., "The YANG 1.1 Data Modeling Language", 843 draft-ietf-netmod-rfc6020bis-09 (work in progress), 844 December 2015. 846 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 847 Requirement Levels", BCP 14, RFC 2119, 848 DOI 10.17487/RFC2119, March 1997, 849 . 851 [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for 852 the Network Configuration Protocol (NETCONF)", RFC 6020, 853 DOI 10.17487/RFC6020, October 2010, 854 . 856 [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", 857 RFC 6991, DOI 10.17487/RFC6991, July 2013, 858 . 860 7.2. Informative References 862 [I-D.amante-i2rs-topology-use-cases] 863 Medved, J., Previdi, S., Lopez, V., and S. Amante, 864 "Topology API Use Cases", draft-amante-i2rs-topology-use- 865 cases-01 (work in progress), October 2013. 867 [I-D.medved-i2rs-topology-requirements] 868 Medved, J., Previdi, S., Gredler, H., Nadeau, T., and S. 869 Amante, "Topology API Requirements", draft-medved-i2rs- 870 topology-requirements-00 (work in progress), February 871 2013. 873 Authors' Addresses 875 Jie Dong 876 Huawei Technologies 877 Huawei Campus, No. 156 Beiqing Rd. 878 Beijing 100095 879 China 881 Email: jie.dong@huawei.com 883 Xiugang Wei 884 Huawei Technologies 885 Huawei Campus, No. 156 Beiqing Rd. 886 Beijing 100095 887 China 889 Email: weixiugang@huawei.com