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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group M. Boucadair 3 Internet-Draft C. Jacquenet 4 Intended status: Standards Track Orange 5 Expires: February 22, 2018 S. Sivakumar 6 Cisco Systems 7 August 21, 2017 9 YANG Data Models for the DS-Lite 10 draft-ietf-softwire-dslite-yang-06 12 Abstract 14 This document defines YANG data models for the DS-Lite Address Family 15 Transition Router (AFTR) and Basic Bridging BroadBand (B4) elements . 17 Status of This Memo 19 This Internet-Draft is submitted in full conformance with the 20 provisions of BCP 78 and BCP 79. 22 Internet-Drafts are working documents of the Internet Engineering 23 Task Force (IETF). Note that other groups may also distribute 24 working documents as Internet-Drafts. The list of current Internet- 25 Drafts is at http://datatracker.ietf.org/drafts/current/. 27 Internet-Drafts are draft documents valid for a maximum of six months 28 and may be updated, replaced, or obsoleted by other documents at any 29 time. It is inappropriate to use Internet-Drafts as reference 30 material or to cite them other than as "work in progress." 32 This Internet-Draft will expire on February 22, 2018. 34 Copyright Notice 36 Copyright (c) 2017 IETF Trust and the persons identified as the 37 document authors. All rights reserved. 39 This document is subject to BCP 78 and the IETF Trust's Legal 40 Provisions Relating to IETF Documents 41 (http://trustee.ietf.org/license-info) in effect on the date of 42 publication of this document. Please review these documents 43 carefully, as they describe your rights and restrictions with respect 44 to this document. Code Components extracted from this document must 45 include Simplified BSD License text as described in Section 4.e of 46 the Trust Legal Provisions and are provided without warranty as 47 described in the Simplified BSD License. 49 Table of Contents 51 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 52 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 53 1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 4 54 2. DS-Lite YANG Data Models . . . . . . . . . . . . . . . . . . 4 55 3. DS-Lite AFTR YANG Module . . . . . . . . . . . . . . . . . . 6 56 4. DS-Lite B4 YANG Module . . . . . . . . . . . . . . . . . . . 12 57 5. Security Considerations . . . . . . . . . . . . . . . . . . . 14 58 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 59 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15 60 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 61 8.1. Normative references . . . . . . . . . . . . . . . . . . 15 62 8.2. Informative references . . . . . . . . . . . . . . . . . 16 63 Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 18 64 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19 66 1. Introduction 68 This document defines data models for DS-Lite [RFC6333], using the 69 YANG data modeling language [RFC6020]. Both the Address Family 70 Transition Router (AFTR) and Basic Bridging BroadBand (B4) elements 71 are covered by this specification. As a reminder, Figure 1 72 illustrates an overview of the DS-Lite architecture that involves 73 AFTR and B4 elements. 75 +-----------+ 76 | Host | 77 +-----+-----+ 78 |10.0.0.1 79 | 80 | 81 |10.0.0.2 82 +---------|---------+ 83 | | | 84 | Home router | 85 |+--------+--------+| 86 || B4 || 87 |+--------+--------+| 88 +--------|||--------+ 89 |||2001:db8:0:1::1 90 ||| 91 |||<-IPv4-in-IPv6 softwire 92 ||| 93 -------|||------- 94 / ||| \ 95 | ISP core network | 96 \ ||| / 97 -------|||------- 98 ||| 99 |||2001:db8:0:2::1 100 +--------|||--------+ 101 | AFTR | 102 |+--------+--------+| 103 || Concentrator || 104 |+--------+--------+| 105 | |NAT| | 106 | +-+-+ | 107 +---------|---------+ 108 |192.0.2.1 109 | 110 --------|-------- 111 / | \ 112 | Internet | 113 \ | / 114 --------|-------- 115 | 116 |198.51.100.1 117 +-----+-----+ 118 | IPv4 Host | 119 +-----------+ 121 Figure 1: DS-Lite Base Architecture 123 DS-Lite deployment considerations are discussed in [RFC6908]. 125 This document follows the guidelines of [RFC6087], uses the common 126 YANG types defined in [RFC6991], and adopts Network Management 127 Datastore Architecture (NMDA). 129 1.1. Terminology 131 This document makes use of the terms defined in [RFC6333]. 133 The terminology for describing YANG data models is defined in 134 [RFC6020]. 136 1.2. Tree Diagrams 138 The meaning of the symbols in these diagrams is as follows: 140 o Brackets "[" and "]" enclose list keys. 142 o Curly braces "{" and "}" contain names of optional features that 143 make the corresponding node conditional. 145 o Abbreviations before data node names: "rw" means configuration 146 (read-write), "ro" state data (read-only). 148 o Symbols after data node names: "?" means an optional node, "!" a 149 container with presence, and "*" denotes a "list" or "leaf-list". 151 o Parentheses enclose choice and case nodes, and case nodes are also 152 marked with a colon (":"). 154 o Ellipsis ("...") stands for contents of subtrees that are not 155 shown. 157 2. DS-Lite YANG Data Models 159 Figure 2 depicts the YANG data model for the AFTR element, while 160 Figure 3 shows the YANG data model for the B4 element. 162 As shown in Figure 1: 164 o The AFTR element is a combination of an IPv4-in-IPv6 165 encapsualtion/decapsulation function and a NAT function. 167 o The B4 element is an IPv4-in-IPv6 encapsulation function. 169 Therefore, the AFTR YANG module is designed to augment both the 170 Interfaces YANG module [RFC7223] and the NAT YANG module 172 [I-D.ietf-opsawg-nat-yang] with DS-Lite specific features. The B4 173 YANG module augments the interfaces YANG module. 175 This document assumes [RFC4787][RFC5382][RFC5508] are enabled by 176 default. Also, the data model adheres to the recommendations in 177 [RFC6888] and [RFC7857]. Furthermore, the data model supports state 178 migration as per [RFC7785]. 180 PCP-related considerations are out of scope of the document. A YANG 181 data model for PCP is documented in [I-D.boucadair-pcp-yang]. 183 module: ietf-dslite-aftr 184 augment /if:interfaces/if:interface: 185 +--rw aftr-ipv6-address? inet:ipv6-address 186 +--rw aftr-ipv4-address? inet:ipv4-address 187 +--rw tunnel-mtu? uint16 188 +--rw max-softwire-per-subscriber? uint8 189 +--rw v6-v4-dscp-preservation? boolean 190 augment /nat:nat-module/nat:nat-instances/nat:nat-instance: 191 +--rw state-migrate? boolean 192 +--rw mss-clamping 193 +--rw mss-clamping-enable? boolean 194 +--rw mss-value? uint16 195 augment /nat:nat-module/nat:nat-instances/nat:nat-instance/nat:mapping-table/nat:mapping-entry: 196 +--rw b4-ipv6-address? inet:ipv6-address 197 +--rw v6-dscp? uint8 198 +--rw internal-v4-dscp? uint8 199 +--rw external-v4-dscp? uint8 201 Figure 2: YANG Data Model for DS-Lite AFTR 203 Examples to illustrate the use of this module are provided in 204 Appendix A. 206 A B4 instance is provided with the IPv6 address of the AFTR to use, 207 an (optional) instruction whether DSCP marking is to preserved when 208 encapsulating an IPv4 packet in an IPv6 packet, and other optional 209 parameters shown in Figure 3. 211 module: ietf-dslite-b4 212 augment /if:interfaces/if:interface: 213 +--rw b4-ipv6-address? inet:ipv6-address 214 +--rw aftr-ipv6-addr? inet:ipv6-address 215 +--rw b4-ipv4-address? inet:ipv4-address 216 +--rw tunnel-mtu? uint16 217 +--rw v6-v4-dscp-preservation? boolean 219 Figure 3: YANG Data Model for DS-Lite B4 221 3. DS-Lite AFTR YANG Module 223 file "ietf-dslite-aftr@2017-08-10.yang" 225 module ietf-dslite-aftr { 226 namespace "urn:ietf:params:xml:ns:yang:ietf-dslite-aftr"; 227 prefix dslite-aftr; 229 import ietf-inet-types { prefix inet; } 230 import ietf-interfaces { prefix if; } 231 import iana-if-type { prefix ianaift; } 232 import ietf-nat {prefix nat;} 234 organization "Softwire Working Group"; 235 contact 236 "Mohamed Boucadair 237 Christian Jacquenet 238 Senthil Sivakumar "; 240 description 241 "This module is a YANG module for DS-Lite AFTR 242 implementations. 244 Copyright (c) 2017 IETF Trust and the persons identified as 245 authors of the code. All rights reserved. 247 Redistribution and use in source and binary forms, with or 248 without modification, is permitted pursuant to, and subject 249 to the license terms contained in, the Simplified BSD License 250 set forth in Section 4.c of the IETF Trust's Legal Provisions 251 Relating to IETF Documents 252 (http://trustee.ietf.org/license-info). 254 This version of this YANG module is part of RFC XXXX; see 255 the RFC itself for full legal notices."; 257 revision 2017-08-10 { 258 description "The module augments also the Interface module."; 259 reference "-ietf-04"; 260 } 262 revision 2017-07-27 { 263 description "Redesign the module as an augment of the NAT YANG module."; 264 reference "-ietf-04"; 265 } 267 revision 2017-07-03 { 268 description "Fix some minor points."; 269 reference "-ietf-03"; 270 } 272 revision 2017-01-03 { 273 description "Fixed a compilation error: 274 https://github.com/mbj4668/pyang/issues/296."; 275 reference "-ietf-02"; 276 } 278 revision 2016-11-14 { 279 description "Integrates the comments from Ian: 280 add B4 module, add an MSS leaf, add more details about 281 logging protocols, and other edits."; 282 reference "-ietf-01"; 283 } 285 revision 2016-07-27 { 286 description "-00 IETF version."; 287 reference "-ietf-00"; 288 } 290 revision 2016-06-13 { 291 description "Update the module."; 292 reference "-04"; 293 } 295 revision 2015-12-16 { 296 description "Fix an error."; 297 reference "-03"; 298 } 300 revision 2015-09-01 { 301 description "Add port threshold notifications."; 302 reference "-02"; 303 } 305 revision 2015-08-31 { 306 description "Fix a timeout issue."; 307 reference "-01"; 308 } 310 revision 2015-08-17 { 311 description "First spec."; 312 reference "-00"; 313 } 315 // Augment Interface module with DS-Lite Softwire 316 augment "/if:interfaces/if:interface" { 317 when "if:type = 'ianaift:tunnel'"; 319 description 320 "Augments Interface module with AFTR parameters. 321 IANA interface types are maintained at this registry: 322 https://www.iana.org/assignments/ianaiftype-mib/ianaiftype-mib. 324 tunnel (131), -- Encapsulation interface"; 326 leaf aftr-ipv6-address { 327 type inet:ipv6-address; 328 description 329 "IPv6 address of the DS-Lite AFTR."; 331 reference 332 "RFC 6333."; 333 } 335 leaf aftr-ipv4-address { 336 type inet:ipv4-address; 337 default "192.0.0.1"; 339 description 340 "IPv4 address of the DS-Lite AFTR. 341 192.0.0.1 is reserved for the AFTR element. 342 This address can be used to report ICMP 343 problems and will appear in traceroute 344 outputs."; 346 reference 347 "RFC 6333."; 348 } 350 leaf tunnel-mtu { 351 type uint16; 353 description 354 "Configures a tunnel MTU. 355 [RFC6908] specifies that since 356 fragmentation and reassembly is not 357 optimal, the operator should do 358 everything possible to eliminate 359 the need for it. If the operator uses 360 simple IPv4-in-IPv6 softwire, it is 361 recommended that the MTU size of the IPv6 362 network between the B4 and the AFTR 363 accounts for the additional overhead 364 (40 bytes)."; 366 reference 367 "RFC 6908."; 368 } 370 leaf max-softwire-per-subscriber { 371 type uint8; 372 default 1; 374 description 375 "Configures the maximum softwire per subscriber 376 feature. 378 A subscriber is uniquely identified by means 379 of subscriber-mask. 381 This policy aims to prevent a misbehaving 382 subscriber from mounting several DS-Lite 383 softwires that would consume additional AFTR 384 resources (e.g., get more external ports if 385 the quota were enforced on a per-softwire basis, 386 consume extra processing due to a large number 387 of active softwires)."; 389 reference 390 "Section 4 of RFC 7785."; 391 } 393 leaf v6-v4-dscp-preservation { 394 type boolean; 396 description 397 "Copies the DSCP value from the IPv6 header 398 and vice versa. 400 According to Section 2.10 of [RFC6908], 401 operators should use this model 402 by provisioning the network such that 403 the AFTR copies the DSCP value in the IPv4 404 header to the Traffic Class field in 405 the IPv6 header, after the encapsulation 406 for the downstream traffic."; 408 reference 409 "Section 2.10 of RFC 6908."; 410 } 411 } 412 // Augment NAT module with AFTR parameters 414 augment "/nat:nat-module/nat:nat-instances/nat:nat-instance" { 416 description 417 "Augments NAT module with AFTR parameters."; 419 leaf state-migrate { 420 type boolean; 421 default true; 423 description 424 "State migration is enabled by default. 426 In the event a new IPv6 address is assigned to the B4 element, 427 the AFTR should migrate existing state to be bound to the new 428 IPv6 address. This operation ensures that traffic destined to 429 the previous B4's IPv6 address will be redirected to the newer 430 B4's IPv6 address. The destination IPv6 address for tunneling 431 return traffic from the AFTR should be the last seen as the B4's 432 IPv6 source address from the CPE. 434 The AFTR uses the subscriber-mask to determine whether two 435 IPv6 addresses belong to the same CPE (e.g., if the 436 subscriber-mask is set to 56, the AFTR concludes that 437 2001:db8:100:100::1 and 2001:db8:100:100::2 belong to the same 438 CPE assigned with 2001:db8:100:100::/56)."; 440 reference 441 "RFC 7785."; 442 } 444 container mss-clamping { 445 description 446 "MSS rewriting configuration to avoid IPv6 447 fragmentation."; 449 leaf mss-clamping-enable { 450 type boolean; 452 description 453 "Enable/disable MSS rewriting feature."; 454 } 456 leaf mss-value { 457 type uint16; 458 units "octets"; 459 description 460 "Sets the MSS value to be used for 461 MSS rewriting."; 462 } 463 } 464 } 466 // Augment NAT mapping entry: Extended NAT44 mapping Entry 468 augment "/nat:nat-module/nat:nat-instances/nat:nat-instance/nat:mapping-table/nat:mapping-entry"{ 469 description 470 "Augments the NAT mapping tables with DS-Lite specifics."; 472 leaf b4-ipv6-address { 473 type inet:ipv6-address; 475 description 476 "Corresponds to the IPv6 address 477 used by the B4 element."; 479 reference 480 "RFC 6333."; 481 } 483 leaf v6-dscp { 484 type uint8; 486 description 487 "DSCP value used at the softwire level 488 (i.e., IPv6 header)."; 489 } 491 leaf internal-v4-dscp { 492 type uint8; 494 description 495 "DSCP value of the encapsulated IPv4 packet."; 496 } 498 leaf external-v4-dscp { 499 type uint8; 501 description 502 "DSCP value of the translated IPv4 packet 503 as marked by the AFTR."; 504 } 505 } 506 } 507 509 4. DS-Lite B4 YANG Module 511 file "ietf-dslite-b4@2017-08-10.yang" 513 module ietf-dslite-b4 { 514 namespace "urn:ietf:params:xml:ns:yang:ietf-dslite-b4"; 515 prefix dslite-b4; 517 import ietf-inet-types { prefix inet; } 518 import ietf-interfaces { prefix if; } 519 import iana-if-type { prefix ianaift; } 521 organization "Softwire Working Group"; 522 contact 523 "Mohamed Boucadair 524 Christian Jacquenet 525 Senthil Sivakumar "; 527 description 528 "This module is a YANG module for DS-Lite B4 implementations. 530 Copyright (c) 2017 IETF Trust and the persons identified as 531 authors of the code. All rights reserved. 533 Redistribution and use in source and binary forms, with or 534 without modification, is permitted pursuant to, and subject 535 to the license terms contained in, the Simplified BSD License 536 set forth in Section 4.c of the IETF Trust's Legal Provisions 537 Relating to IETF Documents 538 (http://trustee.ietf.org/license-info). 540 This version of this YANG module is part of RFC XXXX; see 541 the RFC itself for full legal notices."; 543 revision 2017-08-10 { 544 description "Augment the interfaces YANG module."; 545 reference "-ietf-05"; 546 } 548 revision 2017-07-27 { 549 description "Separate B4 from AFTR."; 550 reference "-ietf-04"; 551 } 553 // Augment Interface module with DS-Lite Softwire 554 augment "/if:interfaces/if:interface" { 555 when "if:type = 'ianaift:tunnel'"; 557 description 558 "Augments Interface module with B4 parameters. 559 IANA interface types are maintained at this registry: 560 https://www.iana.org/assignments/ianaiftype-mib/ianaiftype-mib. 562 tunnel (131), -- Encapsulation interface"; 564 leaf b4-ipv6-address { 565 type inet:ipv6-address; 567 description 568 "The IPv6 address used by the B4 element."; 570 reference 571 "RFC 6333."; 572 } 574 leaf aftr-ipv6-addr { 575 type inet:ipv6-address; 577 description 578 "The AFTR's IPv6 address."; 580 reference 581 "RFC 6333."; 582 } 584 leaf b4-ipv4-address { 585 type inet:ipv4-address; 586 default "192.0.0.2"; 588 description 589 "IPv4 address of the DS-Lite B4. 590 192.0.0.0/29 is reserved for the B4 element 591 [RFC6333]. 592 This address can be used to report ICMP 593 problems and will appear in traceroute 594 outputs."; 596 reference 597 "RFC 6333."; 598 } 600 leaf tunnel-mtu { 601 type uint16; 602 description 603 "Configures a tunnel MTU. 604 [RFC6908] specifies that since 605 fragmentation and reassembly is not 606 optimal, the operator should do 607 everything possible to eliminate 608 the need for it. If the operator uses 609 simple IPv4-in-IPv6 softwire, it is 610 recommended that the MTU size of the IPv6 611 network between the B4 and the AFTR 612 accounts for the additional overhead 613 (40 bytes)."; 615 reference 616 "RFC 6908."; 617 } 619 leaf v6-v4-dscp-preservation { 620 type boolean; 622 description 623 "Copies the DSCP value from the IPv6 header 624 and vice versa. 625 According to Section 2.10 of [RFC6908], 626 operators should use this model 627 by provisioning the network such that 628 the AFTR copies the DSCP value in the IPv4 629 header to the Traffic Class field in 630 the IPv6 header, after the encapsulation 631 for the downstream traffic."; 632 } 633 } 634 } 635 } 636 } 637 639 5. Security Considerations 641 The YANG module defined in this memo is designed to be accessed via 642 the NETCONF protocol [RFC6241]. The lowest NETCONF layer is the 643 secure transport layer and the support of SSH is mandatory to 644 implement secure transport [RFC6242]. The NETCONF access control 645 model [RFC6536] provides means to restrict access for particular 646 NETCONF users to a pre-configured subset of all available NETCONF 647 protocol operations and contents. 649 All data nodes defined in the YANG module which can be created, 650 modified and deleted (i.e., config true, which is the default). 651 These data nodes are considered sensitive. Write operations (e.g., 652 edit-config) applied to these data nodes without proper protection 653 can negatively affect network operations. 655 6. IANA Considerations 657 This document requests IANA to register the following URIs in the 658 "IETF XML Registry" [RFC3688]: 660 URI: urn:ietf:params:xml:ns:yang:ietf-dslite-aftr 661 Registrant Contact: The IESG. 662 XML: N/A; the requested URI is an XML namespace. 664 URI: urn:ietf:params:xml:ns:yang:ietf-dslite-b4 665 Registrant Contact: The IESG. 666 XML: N/A; the requested URI is an XML namespace. 668 This document requests IANA to register the following YANG modules in 669 the "YANG Module Names" registry [RFC6020]. 671 name: ietf-dslite-aftr 672 namespace: urn:ietf:params:xml:ns:yang:ietf-dslite-aftr 673 prefix: dslite-aftr 674 reference: RFC XXXX 676 name: ietf-dslite-b4 677 namespace: urn:ietf:params:xml:ns:yang:ietf-dslite-b4 678 prefix: dslite-b4 679 reference: RFC XXXX 681 7. Acknowledgements 683 Thanks to Q. Wu for identifying a compiling error. 685 Many thanks to Ian Farrer for the review and comments. 687 8. References 689 8.1. Normative references 691 [I-D.ietf-opsawg-nat-yang] 692 Boucadair, M., Sivakumar, S., Jacquenet, C., Vinapamula, 693 S., and Q. Wu, "A YANG Data Model for Network Address 694 Translation (NAT) and Network Prefix Translation (NPT)", 695 draft-ietf-opsawg-nat-yang-01 (work in progress), August 696 2017. 698 [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, 699 DOI 10.17487/RFC3688, January 2004, . 702 [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for 703 the Network Configuration Protocol (NETCONF)", RFC 6020, 704 DOI 10.17487/RFC6020, October 2010, . 707 [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., 708 and A. Bierman, Ed., "Network Configuration Protocol 709 (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, 710 . 712 [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure 713 Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, 714 . 716 [RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual- 717 Stack Lite Broadband Deployments Following IPv4 718 Exhaustion", RFC 6333, DOI 10.17487/RFC6333, August 2011, 719 . 721 [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration 722 Protocol (NETCONF) Access Control Model", RFC 6536, 723 DOI 10.17487/RFC6536, March 2012, . 726 [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", 727 RFC 6991, DOI 10.17487/RFC6991, July 2013, 728 . 730 [RFC7223] Bjorklund, M., "A YANG Data Model for Interface 731 Management", RFC 7223, DOI 10.17487/RFC7223, May 2014, 732 . 734 8.2. Informative references 736 [I-D.boucadair-pcp-yang] 737 Boucadair, M., Jacquenet, C., Sivakumar, S., and S. 738 Vinapamula, "YANG Data Models for the Port Control 739 Protocol (PCP)", draft-boucadair-pcp-yang-04 (work in 740 progress), May 2017. 742 [RFC4787] Audet, F., Ed. and C. Jennings, "Network Address 743 Translation (NAT) Behavioral Requirements for Unicast 744 UDP", BCP 127, RFC 4787, DOI 10.17487/RFC4787, January 745 2007, . 747 [RFC5382] Guha, S., Ed., Biswas, K., Ford, B., Sivakumar, S., and P. 748 Srisuresh, "NAT Behavioral Requirements for TCP", BCP 142, 749 RFC 5382, DOI 10.17487/RFC5382, October 2008, 750 . 752 [RFC5508] Srisuresh, P., Ford, B., Sivakumar, S., and S. Guha, "NAT 753 Behavioral Requirements for ICMP", BCP 148, RFC 5508, 754 DOI 10.17487/RFC5508, April 2009, . 757 [RFC6087] Bierman, A., "Guidelines for Authors and Reviewers of YANG 758 Data Model Documents", RFC 6087, DOI 10.17487/RFC6087, 759 January 2011, . 761 [RFC6888] Perreault, S., Ed., Yamagata, I., Miyakawa, S., Nakagawa, 762 A., and H. Ashida, "Common Requirements for Carrier-Grade 763 NATs (CGNs)", BCP 127, RFC 6888, DOI 10.17487/RFC6888, 764 April 2013, . 766 [RFC6908] Lee, Y., Maglione, R., Williams, C., Jacquenet, C., and M. 767 Boucadair, "Deployment Considerations for Dual-Stack 768 Lite", RFC 6908, DOI 10.17487/RFC6908, March 2013, 769 . 771 [RFC7785] Vinapamula, S. and M. Boucadair, "Recommendations for 772 Prefix Binding in the Context of Softwire Dual-Stack 773 Lite", RFC 7785, DOI 10.17487/RFC7785, February 2016, 774 . 776 [RFC7857] Penno, R., Perreault, S., Boucadair, M., Ed., Sivakumar, 777 S., and K. Naito, "Updates to Network Address Translation 778 (NAT) Behavioral Requirements", BCP 127, RFC 7857, 779 DOI 10.17487/RFC7857, April 2016, . 782 Appendix A. Examples 784 The following example shows an AFTR that is reachable at 2001:db8::2. 785 Also, this XML snippet indicates that the AFTR is provided with an 786 IPv4 address (192.0.0.1) to be used for troubleshooting purposes such 787 as reporting problems to B4s. Moreover, the AFTR is instructed to 788 limit the number of softwires per subscriber to '1'. 790 791 myAFTR 792 ianaift:tunnel 793 true 794 2001:db8::2 795 192.0.0.1 796 1 797 799 The following shows an XML excerpt depicting a dynamic UDP mapping 800 entry maintained by a DS-Lite AFTR. In reference to this example, 801 the UDP packet received with a source IPv6 address (2001:db8::1), a 802 source IPv4 address (192.0.2.1) and source port number (1568) is 803 translated into a UDP packet having a source IPv4 address 804 (198.51.100.1) and source port (15000). The lifetime of this mapping 805 is 300 seconds. 807 808 15 809 810 dynamic-explicit 811 812 813 17 814 815 816 192.0.2.1 817 818 819 192.0.2.1 820 821 822 823 1568 824 825 826 827 198.51.100.1 828 829 830 831 15000 832 833 834 835 300 836 837 839 Authors' Addresses 841 Mohamed Boucadair 842 Orange 843 Rennes 35000 844 France 846 EMail: mohamed.boucadair@orange.com 848 Christian Jacquenet 849 Orange 850 Rennes 35000 851 France 853 EMail: christian.jacquenet@orange.com 854 Senthil Sivakumar 855 Cisco Systems 856 7100-8 Kit Creek Road 857 Research Triangle Park, North Carolina 27709 858 USA 860 Phone: +1 919 392 5158 861 EMail: ssenthil@cisco.com