Network Working Group M. Boucadair Internet-Draft C. Jacquenet Intended status: Standards Track Orange Expires: February 3, 2018 S. Sivakumar Cisco Systems August 2, 2017 YANG Data Models for the DS-Lite draft-ietf-softwire-dslite-yang-04 Abstract This document defines a YANG data model 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 3, 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 3, 2018 [Page 1] Internet-Draft DS-Lite YANG August 2017 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2 1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 2 2. DS-Lite YANG Data Models . . . . . . . . . . . . . . . . . . 3 3. DS-Lite AFTR YANG Module . . . . . . . . . . . . . . . . . . 4 4. DS-Lite B4 YANG Module . . . . . . . . . . . . . . . . . . . 10 5. Security Considerations . . . . . . . . . . . . . . . . . . . 13 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 8.1. Normative references . . . . . . . . . . . . . . . . . . 14 8.2. Informative references . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 1. Introduction This document defines a data model 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. DS-Lite deployment considerations are discussed in [RFC6908]. This document follows the guidelines of [RFC6087]. This document uses the common YANG types defined in [RFC6991]. 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). Boucadair, et al. Expires February 3, 2018 [Page 2] Internet-Draft DS-Lite YANG August 2017 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 1 depicts the YANG data model for the AFTR, while Figure 2 shows the YANG data model for the B4 element. The AFTR model supports enabling one or more instances of the AFTR function on a device; each instance is responsible for serving a group of B4s. The data model assumes that each AFTR instance can: be enable/disabled, be provisioned with dedicated configuration data, and maintain its own mapping table. The data model assumes that pools of IPv4 addresses can be provisioned to the AFTR. The AFTR module augments the NAT module in [I-D.sivakumar-yang-nat]. As such, this document assumes [RFC4787][RFC5382][RFC5508] are enabled by default. Also, the data model adheres to the recommendations in [RFC6888] and [RFC7857]. Further, 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]. Boucadair, et al. Expires February 3, 2018 [Page 3] Internet-Draft DS-Lite YANG August 2017 module: ietf-dslite-aftr augment /nat:nat-module/nat:nat-instances/nat:nat-instance: +--rw ipv6-address? inet:ipv6-address +--rw ipv4-address? inet:ipv4-address +--rw tunnel-mtu? uint16 +--rw subscriber-mask? uint8 +--rw state-migrate? boolean +--rw max-softwire-per-subscriber? uint8 +--rw mss-clamping | +--rw mss-clamping-enable? boolean | +--rw mss-value? uint16 +--rw v6-v4-dscp-preservation? boolean augment /nat:nat-module/nat:nat-instances/nat:nat-instance/nat:mapping-table/nat:mapping-entry: +--rw b4-ip-address? inet:ipv6-address +--rw v6-dscp? uint8 +--rw internal-v4-dscp? uint8 +--rw external-v4-dscp? uint8 Figure 1: YANG Data Model for DS-Lite AFTR module: ietf-dslite-b4 +--rw dslite-b4 +--rw enable? boolean +--rw dslite-b4-instances +--rw dslite-b4-instance* [id] +--rw id uint32 +--rw name? string +--rw aftr-ipv6-addr inet:ipv6-address +--rw ipv4-address? inet:ipv4-address +--rw tunnel-mtu? uint16 +--rw v6-v4-dscp-preservation boolean Figure 2: YANG Data Model for DS-Lite B4 3. DS-Lite AFTR YANG Module file "ietf-dslite-aftr@2017-07-27.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-nat { prefix nat; } Boucadair, et al. Expires February 3, 2018 [Page 4] Internet-Draft DS-Lite YANG August 2017 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 2017-07-27 { description "Redesign the module as an augment of the NAT YANG module."; reference "-ietf-04"; } revision 2017-07-03 { description "Fix some minor points."; 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."; Boucadair, et al. Expires February 3, 2018 [Page 5] Internet-Draft DS-Lite YANG August 2017 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 NAT module with AFTR parameters augment "/nat:nat-module/nat:nat-instances/nat:nat-instance" { description "Augments NAT module with AFTR parameters."; leaf ipv6-address { type inet:ipv6-address; description "IPv6 address of the dslite-aftr."; reference "RFC 6333."; } leaf ipv4-address { type inet:ipv4-address; default "192.0.0.1"; description Boucadair, et al. Expires February 3, 2018 [Page 6] Internet-Draft DS-Lite YANG August 2017 "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 (40 bytes)."; reference "RFC 6908."; } leaf subscriber-mask { type uint8 { range "0 .. 128"; } default "56"; description "The subscriber-mask is an integer that indicates the length of significant bits to be applied on the source IPv6 address (internal side) to unambiguously identify a CPE. Subscriber-mask is a system-wide configuration parameter that is used to enforce generic per-subscriber policies (e.g., port-quota). The enforcement of these generic policies does not require the configuration of every subscriber's prefix. Example: suppose the 2001:db8:100:100::/56 prefix is Boucadair, et al. Expires February 3, 2018 [Page 7] Internet-Draft DS-Lite YANG August 2017 assigned to a DS-Lite enabled CPE. Suppose also that the 2001:db8:100:100::1 is the IPv6 address used by the B4 that resides in that CPE. When the AFTR receives a packet from this client, it applies the subscriber-mask (e.g., 56) on the source IPv6 address to compute the associated prefix for this client (that is 2001:db8:100:100::/56). Then, the AFTR enforces policies based on that prefix (2001:db8:100:100::/56), not on the exact source IPv6 address"; reference "RFC 7785."; } leaf state-migrate { type boolean; default true; description "State migration is enabled by default."; reference "RFC 7785."; } 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."; } container mss-clamping { Boucadair, et al. Expires February 3, 2018 [Page 8] Internet-Draft DS-Lite YANG August 2017 description "MSS rewriting configuration."; leaf mss-clamping-enable { type boolean; description "Enable/disable MSS rewriting feature."; } leaf mss-value { type uint16; units "octets"; description "Sets the MSS value to be used for MSS rewriting."; } } 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."; } } // 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 table with DS-Lite specifics."; leaf b4-ip-address { type inet:ipv6-address; description "Corresponds to the IPv6 address used by the B4 element."; Boucadair, et al. Expires February 3, 2018 [Page 9] Internet-Draft DS-Lite YANG August 2017 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."; } } } 4. DS-Lite B4 YANG Module file "ietf-dslite-b4@2017-07-27.yang" module ietf-dslite-b4 { namespace "urn:ietf:params:xml:ns:yang:ietf-dslite-b4"; prefix dslite-b4; import ietf-inet-types { prefix inet; } 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. Boucadair, et al. Expires February 3, 2018 [Page 10] Internet-Draft DS-Lite YANG August 2017 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 2017-07-27 { description "Separate B4 from AFTR."; reference "-ietf-04"; } container dslite-b4 { description "dslite-b4"; leaf enable { type boolean; description "Enable/disable dslite-b4 function."; } container dslite-b4-instances { description "dslite-b4 instances"; list dslite-b4-instance { key "id"; description "a dslite-b4 instance."; leaf id { type uint32; description "dslite-b4 instance identifier."; } leaf name { type string; description "A name associated with the dslite-b4 instance."; } leaf aftr-ipv6-addr { Boucadair, et al. Expires February 3, 2018 [Page 11] Internet-Draft DS-Lite YANG August 2017 type inet:ipv6-address; mandatory true; description "The AFTR's IPv6 address."; reference "RFC 6333."; } leaf 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; 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; mandatory true; description "Copies the DSCP value from the IPv6 header Boucadair, et al. Expires February 3, 2018 [Page 12] Internet-Draft DS-Lite YANG August 2017 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. 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]. Boucadair, et al. Expires February 3, 2018 [Page 13] Internet-Draft DS-Lite YANG August 2017 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 [I-D.sivakumar-yang-nat] Sivakumar, S., Boucadair, M., and S. Vinapamula, "YANG Data Model for Network Address Translation (NAT)", draft- sivakumar-yang-nat-07 (work in progress), July 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, . Boucadair, et al. Expires February 3, 2018 [Page 14] Internet-Draft DS-Lite YANG August 2017 [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, . 8.2. Informative references [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, . Boucadair, et al. Expires February 3, 2018 [Page 15] Internet-Draft DS-Lite YANG August 2017 [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, . Authors' Addresses Mohamed Boucadair Orange Rennes 35000 France EMail: mohamed.boucadair@orange.com Christian Jacquenet Orange Rennes 35000 France EMail: christian.jacquenet@orange.com 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 3, 2018 [Page 16]