Network Working Group M. Boucadair Internet-Draft C. Jacquenet Intended status: Standards Track Orange Expires: February 22, 2018 S. Sivakumar Cisco Systems August 21, 2017 YANG Data Models for the DS-Lite draft-ietf-softwire-dslite-yang-06 Abstract This document defines YANG data models for the DS-Lite Address Family Transition Router (AFTR) and Basic Bridging BroadBand (B4) elements . Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on February 22, 2018. Copyright Notice Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Boucadair, et al. Expires February 22, 2018 [Page 1] Internet-Draft DS-Lite YANG August 2017 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 4 2. DS-Lite YANG Data Models . . . . . . . . . . . . . . . . . . 4 3. DS-Lite AFTR YANG Module . . . . . . . . . . . . . . . . . . 6 4. DS-Lite B4 YANG Module . . . . . . . . . . . . . . . . . . . 12 5. Security Considerations . . . . . . . . . . . . . . . . . . . 14 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 8.1. Normative references . . . . . . . . . . . . . . . . . . 15 8.2. Informative references . . . . . . . . . . . . . . . . . 16 Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19 1. Introduction This document defines data models for DS-Lite [RFC6333], using the YANG data modeling language [RFC6020]. Both the Address Family Transition Router (AFTR) and Basic Bridging BroadBand (B4) elements are covered by this specification. As a reminder, Figure 1 illustrates an overview of the DS-Lite architecture that involves AFTR and B4 elements. Boucadair, et al. Expires February 22, 2018 [Page 2] Internet-Draft DS-Lite YANG August 2017 +-----------+ | Host | +-----+-----+ |10.0.0.1 | | |10.0.0.2 +---------|---------+ | | | | Home router | |+--------+--------+| || B4 || |+--------+--------+| +--------|||--------+ |||2001:db8:0:1::1 ||| |||<-IPv4-in-IPv6 softwire ||| -------|||------- / ||| \ | ISP core network | \ ||| / -------|||------- ||| |||2001:db8:0:2::1 +--------|||--------+ | AFTR | |+--------+--------+| || Concentrator || |+--------+--------+| | |NAT| | | +-+-+ | +---------|---------+ |192.0.2.1 | --------|-------- / | \ | Internet | \ | / --------|-------- | |198.51.100.1 +-----+-----+ | IPv4 Host | +-----------+ Figure 1: DS-Lite Base Architecture Boucadair, et al. Expires February 22, 2018 [Page 3] Internet-Draft DS-Lite YANG August 2017 DS-Lite deployment considerations are discussed in [RFC6908]. This document follows the guidelines of [RFC6087], uses the common YANG types defined in [RFC6991], and adopts Network Management Datastore Architecture (NMDA). 1.1. Terminology This document makes use of the terms defined in [RFC6333]. The terminology for describing YANG data models is defined in [RFC6020]. 1.2. Tree Diagrams The meaning of the symbols in these diagrams is as follows: o Brackets "[" and "]" enclose list keys. o Curly braces "{" and "}" contain names of optional features that make the corresponding node conditional. o Abbreviations before data node names: "rw" means configuration (read-write), "ro" state data (read-only). o Symbols after data node names: "?" means an optional node, "!" a container with presence, and "*" denotes a "list" or "leaf-list". o Parentheses enclose choice and case nodes, and case nodes are also marked with a colon (":"). o Ellipsis ("...") stands for contents of subtrees that are not shown. 2. DS-Lite YANG Data Models Figure 2 depicts the YANG data model for the AFTR element, while Figure 3 shows the YANG data model for the B4 element. As shown in Figure 1: o The AFTR element is a combination of an IPv4-in-IPv6 encapsualtion/decapsulation function and a NAT function. o The B4 element is an IPv4-in-IPv6 encapsulation function. Therefore, the AFTR YANG module is designed to augment both the Interfaces YANG module [RFC7223] and the NAT YANG module Boucadair, et al. Expires February 22, 2018 [Page 4] Internet-Draft DS-Lite YANG August 2017 [I-D.ietf-opsawg-nat-yang] with DS-Lite specific features. The B4 YANG module augments the interfaces YANG module. This document assumes [RFC4787][RFC5382][RFC5508] are enabled by default. Also, the data model adheres to the recommendations in [RFC6888] and [RFC7857]. Furthermore, the data model supports state migration as per [RFC7785]. PCP-related considerations are out of scope of the document. A YANG data model for PCP is documented in [I-D.boucadair-pcp-yang]. module: ietf-dslite-aftr augment /if:interfaces/if:interface: +--rw aftr-ipv6-address? inet:ipv6-address +--rw aftr-ipv4-address? inet:ipv4-address +--rw tunnel-mtu? uint16 +--rw max-softwire-per-subscriber? uint8 +--rw v6-v4-dscp-preservation? boolean augment /nat:nat-module/nat:nat-instances/nat:nat-instance: +--rw state-migrate? boolean +--rw mss-clamping +--rw mss-clamping-enable? boolean +--rw mss-value? uint16 augment /nat:nat-module/nat:nat-instances/nat:nat-instance/nat:mapping-table/nat:mapping-entry: +--rw b4-ipv6-address? inet:ipv6-address +--rw v6-dscp? uint8 +--rw internal-v4-dscp? uint8 +--rw external-v4-dscp? uint8 Figure 2: YANG Data Model for DS-Lite AFTR Examples to illustrate the use of this module are provided in Appendix A. A B4 instance is provided with the IPv6 address of the AFTR to use, an (optional) instruction whether DSCP marking is to preserved when encapsulating an IPv4 packet in an IPv6 packet, and other optional parameters shown in Figure 3. module: ietf-dslite-b4 augment /if:interfaces/if:interface: +--rw b4-ipv6-address? inet:ipv6-address +--rw aftr-ipv6-addr? inet:ipv6-address +--rw b4-ipv4-address? inet:ipv4-address +--rw tunnel-mtu? uint16 +--rw v6-v4-dscp-preservation? boolean Figure 3: YANG Data Model for DS-Lite B4 Boucadair, et al. Expires February 22, 2018 [Page 5] Internet-Draft DS-Lite YANG August 2017 3. DS-Lite AFTR YANG Module file "ietf-dslite-aftr@2017-08-10.yang" module ietf-dslite-aftr { namespace "urn:ietf:params:xml:ns:yang:ietf-dslite-aftr"; prefix dslite-aftr; import ietf-inet-types { prefix inet; } import ietf-interfaces { prefix if; } import iana-if-type { prefix ianaift; } import ietf-nat {prefix nat;} organization "Softwire Working Group"; contact "Mohamed Boucadair Christian Jacquenet Senthil Sivakumar "; description "This module is a YANG module for DS-Lite AFTR implementations. Copyright (c) 2017 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; revision 2017-08-10 { description "The module augments also the Interface module."; reference "-ietf-04"; } revision 2017-07-27 { description "Redesign the module as an augment of the NAT YANG module."; reference "-ietf-04"; } revision 2017-07-03 { description "Fix some minor points."; Boucadair, et al. Expires February 22, 2018 [Page 6] Internet-Draft DS-Lite YANG August 2017 reference "-ietf-03"; } revision 2017-01-03 { description "Fixed a compilation error: https://github.com/mbj4668/pyang/issues/296."; reference "-ietf-02"; } revision 2016-11-14 { description "Integrates the comments from Ian: add B4 module, add an MSS leaf, add more details about logging protocols, and other edits."; reference "-ietf-01"; } revision 2016-07-27 { description "-00 IETF version."; reference "-ietf-00"; } revision 2016-06-13 { description "Update the module."; reference "-04"; } revision 2015-12-16 { description "Fix an error."; reference "-03"; } revision 2015-09-01 { description "Add port threshold notifications."; reference "-02"; } revision 2015-08-31 { description "Fix a timeout issue."; reference "-01"; } revision 2015-08-17 { description "First spec."; reference "-00"; } // Augment Interface module with DS-Lite Softwire Boucadair, et al. Expires February 22, 2018 [Page 7] Internet-Draft DS-Lite YANG August 2017 augment "/if:interfaces/if:interface" { when "if:type = 'ianaift:tunnel'"; description "Augments Interface module with AFTR parameters. IANA interface types are maintained at this registry: https://www.iana.org/assignments/ianaiftype-mib/ianaiftype-mib. tunnel (131), -- Encapsulation interface"; leaf aftr-ipv6-address { type inet:ipv6-address; description "IPv6 address of the DS-Lite AFTR."; reference "RFC 6333."; } leaf aftr-ipv4-address { type inet:ipv4-address; default "192.0.0.1"; description "IPv4 address of the DS-Lite AFTR. 192.0.0.1 is reserved for the AFTR element. This address can be used to report ICMP problems and will appear in traceroute outputs."; reference "RFC 6333."; } leaf tunnel-mtu { type uint16; description "Configures a tunnel MTU. [RFC6908] specifies that since fragmentation and reassembly is not optimal, the operator should do everything possible to eliminate the need for it. If the operator uses simple IPv4-in-IPv6 softwire, it is recommended that the MTU size of the IPv6 network between the B4 and the AFTR accounts for the additional overhead Boucadair, et al. Expires February 22, 2018 [Page 8] Internet-Draft DS-Lite YANG August 2017 (40 bytes)."; reference "RFC 6908."; } leaf max-softwire-per-subscriber { type uint8; default 1; description "Configures the maximum softwire per subscriber feature. A subscriber is uniquely identified by means of subscriber-mask. This policy aims to prevent a misbehaving subscriber from mounting several DS-Lite softwires that would consume additional AFTR resources (e.g., get more external ports if the quota were enforced on a per-softwire basis, consume extra processing due to a large number of active softwires)."; reference "Section 4 of RFC 7785."; } leaf v6-v4-dscp-preservation { type boolean; description "Copies the DSCP value from the IPv6 header and vice versa. According to Section 2.10 of [RFC6908], operators should use this model by provisioning the network such that the AFTR copies the DSCP value in the IPv4 header to the Traffic Class field in the IPv6 header, after the encapsulation for the downstream traffic."; reference "Section 2.10 of RFC 6908."; } } Boucadair, et al. Expires February 22, 2018 [Page 9] Internet-Draft DS-Lite YANG August 2017 // Augment NAT module with AFTR parameters augment "/nat:nat-module/nat:nat-instances/nat:nat-instance" { description "Augments NAT module with AFTR parameters."; leaf state-migrate { type boolean; default true; description "State migration is enabled by default. In the event a new IPv6 address is assigned to the B4 element, the AFTR should migrate existing state to be bound to the new IPv6 address. This operation ensures that traffic destined to the previous B4's IPv6 address will be redirected to the newer B4's IPv6 address. The destination IPv6 address for tunneling return traffic from the AFTR should be the last seen as the B4's IPv6 source address from the CPE. The AFTR uses the subscriber-mask to determine whether two IPv6 addresses belong to the same CPE (e.g., if the subscriber-mask is set to 56, the AFTR concludes that 2001:db8:100:100::1 and 2001:db8:100:100::2 belong to the same CPE assigned with 2001:db8:100:100::/56)."; reference "RFC 7785."; } container mss-clamping { description "MSS rewriting configuration to avoid IPv6 fragmentation."; leaf mss-clamping-enable { type boolean; description "Enable/disable MSS rewriting feature."; } leaf mss-value { type uint16; units "octets"; Boucadair, et al. Expires February 22, 2018 [Page 10] Internet-Draft DS-Lite YANG August 2017 description "Sets the MSS value to be used for MSS rewriting."; } } } // Augment NAT mapping entry: Extended NAT44 mapping Entry augment "/nat:nat-module/nat:nat-instances/nat:nat-instance/nat:mapping-table/nat:mapping-entry"{ description "Augments the NAT mapping tables with DS-Lite specifics."; leaf b4-ipv6-address { type inet:ipv6-address; description "Corresponds to the IPv6 address used by the B4 element."; reference "RFC 6333."; } leaf v6-dscp { type uint8; description "DSCP value used at the softwire level (i.e., IPv6 header)."; } leaf internal-v4-dscp { type uint8; description "DSCP value of the encapsulated IPv4 packet."; } leaf external-v4-dscp { type uint8; description "DSCP value of the translated IPv4 packet as marked by the AFTR."; } } } Boucadair, et al. Expires February 22, 2018 [Page 11] Internet-Draft DS-Lite YANG August 2017 4. DS-Lite B4 YANG Module file "ietf-dslite-b4@2017-08-10.yang" module ietf-dslite-b4 { namespace "urn:ietf:params:xml:ns:yang:ietf-dslite-b4"; prefix dslite-b4; import ietf-inet-types { prefix inet; } import ietf-interfaces { prefix if; } import iana-if-type { prefix ianaift; } organization "Softwire Working Group"; contact "Mohamed Boucadair Christian Jacquenet Senthil Sivakumar "; description "This module is a YANG module for DS-Lite B4 implementations. Copyright (c) 2017 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; revision 2017-08-10 { description "Augment the interfaces YANG module."; reference "-ietf-05"; } revision 2017-07-27 { description "Separate B4 from AFTR."; reference "-ietf-04"; } // Augment Interface module with DS-Lite Softwire Boucadair, et al. Expires February 22, 2018 [Page 12] Internet-Draft DS-Lite YANG August 2017 augment "/if:interfaces/if:interface" { when "if:type = 'ianaift:tunnel'"; description "Augments Interface module with B4 parameters. IANA interface types are maintained at this registry: https://www.iana.org/assignments/ianaiftype-mib/ianaiftype-mib. tunnel (131), -- Encapsulation interface"; leaf b4-ipv6-address { type inet:ipv6-address; description "The IPv6 address used by the B4 element."; reference "RFC 6333."; } leaf aftr-ipv6-addr { type inet:ipv6-address; description "The AFTR's IPv6 address."; reference "RFC 6333."; } leaf b4-ipv4-address { type inet:ipv4-address; default "192.0.0.2"; description "IPv4 address of the DS-Lite B4. 192.0.0.0/29 is reserved for the B4 element [RFC6333]. This address can be used to report ICMP problems and will appear in traceroute outputs."; reference "RFC 6333."; } leaf tunnel-mtu { type uint16; Boucadair, et al. Expires February 22, 2018 [Page 13] Internet-Draft DS-Lite YANG August 2017 description "Configures a tunnel MTU. [RFC6908] specifies that since fragmentation and reassembly is not optimal, the operator should do everything possible to eliminate the need for it. If the operator uses simple IPv4-in-IPv6 softwire, it is recommended that the MTU size of the IPv6 network between the B4 and the AFTR accounts for the additional overhead (40 bytes)."; reference "RFC 6908."; } leaf v6-v4-dscp-preservation { type boolean; description "Copies the DSCP value from the IPv6 header and vice versa. According to Section 2.10 of [RFC6908], operators should use this model by provisioning the network such that the AFTR copies the DSCP value in the IPv4 header to the Traffic Class field in the IPv6 header, after the encapsulation for the downstream traffic."; } } } } } 5. Security Considerations The YANG module defined in this memo is designed to be accessed via the NETCONF protocol [RFC6241]. The lowest NETCONF layer is the secure transport layer and the support of SSH is mandatory to implement secure transport [RFC6242]. The NETCONF access control model [RFC6536] provides means to restrict access for particular NETCONF users to a pre-configured subset of all available NETCONF protocol operations and contents. Boucadair, et al. Expires February 22, 2018 [Page 14] Internet-Draft DS-Lite YANG August 2017 All data nodes defined in the YANG module which can be created, modified and deleted (i.e., config true, which is the default). These data nodes are considered sensitive. Write operations (e.g., edit-config) applied to these data nodes without proper protection can negatively affect network operations. 6. IANA Considerations This document requests IANA to register the following URIs in the "IETF XML Registry" [RFC3688]: URI: urn:ietf:params:xml:ns:yang:ietf-dslite-aftr Registrant Contact: The IESG. XML: N/A; the requested URI is an XML namespace. URI: urn:ietf:params:xml:ns:yang:ietf-dslite-b4 Registrant Contact: The IESG. XML: N/A; the requested URI is an XML namespace. This document requests IANA to register the following YANG modules in the "YANG Module Names" registry [RFC6020]. name: ietf-dslite-aftr namespace: urn:ietf:params:xml:ns:yang:ietf-dslite-aftr prefix: dslite-aftr reference: RFC XXXX name: ietf-dslite-b4 namespace: urn:ietf:params:xml:ns:yang:ietf-dslite-b4 prefix: dslite-b4 reference: RFC XXXX 7. Acknowledgements Thanks to Q. Wu for identifying a compiling error. Many thanks to Ian Farrer for the review and comments. 8. References 8.1. Normative references Boucadair, et al. Expires February 22, 2018 [Page 15] Internet-Draft DS-Lite YANG August 2017 [I-D.ietf-opsawg-nat-yang] Boucadair, M., Sivakumar, S., Jacquenet, C., Vinapamula, S., and Q. Wu, "A YANG Data Model for Network Address Translation (NAT) and Network Prefix Translation (NPT)", draft-ietf-opsawg-nat-yang-01 (work in progress), August 2017. [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, . [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, . [RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual- Stack Lite Broadband Deployments Following IPv4 Exhaustion", RFC 6333, DOI 10.17487/RFC6333, August 2011, . [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, DOI 10.17487/RFC6536, March 2012, . [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, . [RFC7223] Bjorklund, M., "A YANG Data Model for Interface Management", RFC 7223, DOI 10.17487/RFC7223, May 2014, . 8.2. Informative references Boucadair, et al. Expires February 22, 2018 [Page 16] Internet-Draft DS-Lite YANG August 2017 [I-D.boucadair-pcp-yang] Boucadair, M., Jacquenet, C., Sivakumar, S., and S. Vinapamula, "YANG Data Models for the Port Control Protocol (PCP)", draft-boucadair-pcp-yang-04 (work in progress), May 2017. [RFC4787] Audet, F., Ed. and C. Jennings, "Network Address Translation (NAT) Behavioral Requirements for Unicast UDP", BCP 127, RFC 4787, DOI 10.17487/RFC4787, January 2007, . [RFC5382] Guha, S., Ed., Biswas, K., Ford, B., Sivakumar, S., and P. Srisuresh, "NAT Behavioral Requirements for TCP", BCP 142, RFC 5382, DOI 10.17487/RFC5382, October 2008, . [RFC5508] Srisuresh, P., Ford, B., Sivakumar, S., and S. Guha, "NAT Behavioral Requirements for ICMP", BCP 148, RFC 5508, DOI 10.17487/RFC5508, April 2009, . [RFC6087] Bierman, A., "Guidelines for Authors and Reviewers of YANG Data Model Documents", RFC 6087, DOI 10.17487/RFC6087, January 2011, . [RFC6888] Perreault, S., Ed., Yamagata, I., Miyakawa, S., Nakagawa, A., and H. Ashida, "Common Requirements for Carrier-Grade NATs (CGNs)", BCP 127, RFC 6888, DOI 10.17487/RFC6888, April 2013, . [RFC6908] Lee, Y., Maglione, R., Williams, C., Jacquenet, C., and M. Boucadair, "Deployment Considerations for Dual-Stack Lite", RFC 6908, DOI 10.17487/RFC6908, March 2013, . [RFC7785] Vinapamula, S. and M. Boucadair, "Recommendations for Prefix Binding in the Context of Softwire Dual-Stack Lite", RFC 7785, DOI 10.17487/RFC7785, February 2016, . [RFC7857] Penno, R., Perreault, S., Boucadair, M., Ed., Sivakumar, S., and K. Naito, "Updates to Network Address Translation (NAT) Behavioral Requirements", BCP 127, RFC 7857, DOI 10.17487/RFC7857, April 2016, . Boucadair, et al. Expires February 22, 2018 [Page 17] Internet-Draft DS-Lite YANG August 2017 Appendix A. Examples The following example shows an AFTR that is reachable at 2001:db8::2. Also, this XML snippet indicates that the AFTR is provided with an IPv4 address (192.0.0.1) to be used for troubleshooting purposes such as reporting problems to B4s. Moreover, the AFTR is instructed to limit the number of softwires per subscriber to '1'. myAFTR ianaift:tunnel true 2001:db8::2 192.0.0.1 1 The following shows an XML excerpt depicting a dynamic UDP mapping entry maintained by a DS-Lite AFTR. In reference to this example, the UDP packet received with a source IPv6 address (2001:db8::1), a source IPv4 address (192.0.2.1) and source port number (1568) is translated into a UDP packet having a source IPv4 address (198.51.100.1) and source port (15000). The lifetime of this mapping is 300 seconds. Boucadair, et al. Expires February 22, 2018 [Page 18] Internet-Draft DS-Lite YANG August 2017 15 dynamic-explicit 17 192.0.2.1 192.0.2.1 1568 198.51.100.1 15000 300 Authors' Addresses Mohamed Boucadair Orange Rennes 35000 France EMail: mohamed.boucadair@orange.com Christian Jacquenet Orange Rennes 35000 France EMail: christian.jacquenet@orange.com Boucadair, et al. Expires February 22, 2018 [Page 19] Internet-Draft DS-Lite YANG August 2017 Senthil Sivakumar Cisco Systems 7100-8 Kit Creek Road Research Triangle Park, North Carolina 27709 USA Phone: +1 919 392 5158 EMail: ssenthil@cisco.com Boucadair, et al. Expires February 22, 2018 [Page 20]