--- 1/draft-ietf-bfd-unsolicited-06.txt 2021-10-25 12:14:03.444512639 -0700 +++ 2/draft-ietf-bfd-unsolicited-07.txt 2021-10-25 12:14:03.472513342 -0700 @@ -1,22 +1,22 @@ Network Working Group E. Chen Internet-Draft Palo Alto Networks Intended status: Standards Track N. Shen -Expires: April 24, 2022 Zededa +Expires: 27 April 2022 Zededa R. Raszuk NTT Network Innovations R. Rahman - October 21, 2021 + 24 October 2021 Unsolicited BFD for Sessionless Applications - draft-ietf-bfd-unsolicited-06 + draft-ietf-bfd-unsolicited-07 Abstract For operational simplification of "sessionless" applications using BFD, in this document we present procedures for "unsolicited BFD" that allow a BFD session to be initiated by only one side, and be established without explicit per-session configuration or registration by the other side (subject to certain per-interface or per-router policies). @@ -36,73 +36,72 @@ 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 https://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 April 24, 2022. + This Internet-Draft will expire on 27 April 2022. Copyright Notice Copyright (c) 2021 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 - (https://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. + Provisions Relating to IETF Documents (https://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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Procedures for Unsolicited BFD . . . . . . . . . . . . . . . 3 3. State Variables . . . . . . . . . . . . . . . . . . . . . . . 4 - 4. YANG Data Model . . . . . . . . . . . . . . . . . . . . . . . 4 + 4. YANG Data Model . . . . . . . . . . . . . . . . . . . . . . . 5 4.1. Unsolicited BFD Hierarchy . . . . . . . . . . . . . . . . 5 4.2. Unsolicited BFD Module . . . . . . . . . . . . . . . . . 5 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 7.1. BFD Protocol Security Considerations . . . . . . . . . . 9 - 7.2. YANG Module Security Considerations . . . . . . . . . . . 9 - 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 8.1. Normative References . . . . . . . . . . . . . . . . . . 10 + 7.2. YANG Module Security Considerations . . . . . . . . . . . 10 + 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 + 8.1. Normative References . . . . . . . . . . . . . . . . . . 11 8.2. Informative References . . . . . . . . . . . . . . . . . 12 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 1. Introduction The current implementation and deployment practice for BFD ([RFC5880] and [RFC5881]) usually requires BFD sessions be explicitly configured or registered on both sides. This requirement is not an issue when an application like BGP [RFC4271] has the concept of a "session" that involves both sides for its establishment. However, this requirement can be operationally challenging when the prerequisite "session" does not naturally exist between two endpoints in an application. Simultaneous configuration and coordination may be required on both sides for BFD to take effect. For example: - o When BFD is used to keep track of the "liveness" of the nexthop of + * When BFD is used to keep track of the "liveness" of the nexthop of static routes. Although only one side may need the BFD functionality, currently both sides need to be involved in specific configuration and coordination and in some cases static routes are created unnecessarily just for BFD. - o When BFD is used to keep track of the "liveness" of the third-pary + * When BFD is used to keep track of the "liveness" of the third-pary nexthop of BGP routes received from the Route Server [RFC7947] at an Internet Exchange Point (IXP). As the third-party nexthop is different from the peering address of the Route Server, for BFD to work, currently two routers peering with the Route Server need to have routes and nexthops from each other (although indirectly via the Router Server), and the nexthop of each router must be present at the same time. These issues are also discussed in [I-D.ietf-idr-rs-bfd]. Clearly it is beneficial and desirable to reduce or eliminate @@ -216,32 +214,31 @@ +--:(single-interval) {single-minimum-interval}? +--rw min-interval? uint32 augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/bfd:bfd/bfd-ip-sh:ip-sh /bfd-ip-sh:sessions/bfd-ip-sh:session: +--ro unsolicited +--ro role? bfd-unsol:unsolicited-role 4.2. Unsolicited BFD Module - file "ietf-bfd-unsolicited@2021-10-21.yang" - + file "ietf-bfd-unsolicited@2021-10-24.yang" module ietf-bfd-unsolicited { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-bfd-unsolicited"; - prefix "bfd-unsol"; // RFC Ed.: replace occurences of YYYY with actual RFC numbers // and remove this note + import ietf-bfd-types { prefix "bfd-types"; reference "RFC 9127: YANG Data Model for BFD"; } import ietf-bfd { prefix "bfd"; reference "RFC 9127: YANG Data Model for BFD"; } @@ -253,21 +250,21 @@ import ietf-routing { prefix "rt"; reference "RFC 8349: A YANG Data Model for Routing Management (NMDA version)"; } organization "IETF BFD Working Group"; contact - "WG Web: + "WG Web: WG List: Editors: Enke Chen (enchen@paloaltonetworks.com), Naiming Shen (naiming@zededa.com), Robert Raszuk (robert@raszuk.net), Reshad Rahman (reshad@yahoo.com)"; description "This module contains the YANG definition for BFD unsolicited as per RFC YYYY. @@ -280,23 +277,23 @@ 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 YYYY; see the RFC itself for full legal notices."; reference "RFC YYYY"; - revision 2021-10-21 { + revision 2021-10-24 { description "Initial revision."; - reference "RFC YYYY: A YANG data model for BFD unsolicited"; + reference "RFC YYYY: Unsolicited BFD for Sessionless Applications."; } /* * Feature definitions */ feature unsolicited-params-global { description "This feature indicates that the server supports global parameters for unsolicited sessions."; } @@ -367,58 +364,77 @@ + "bfd-ip-sh:sessions/bfd-ip-sh:session" { description "Augmentation for BFD unsolicited on IP single-hop session"; container unsolicited { config false; description "BFD IP single-hop session unsolicited top level container"; leaf role { type bfd-unsol:unsolicited-role; description "Role."; + } } } } 5. IANA Considerations - This documents makes no IANA requests. + This document registers the following namespace URI in the "IETF XML + Registry" [RFC3688]: + + URI: urn:ietf:params:xml:ns:yang:ietf-bfd-unsolicited + + Registrant Contact: The IESG. + + XML: N/A; the requested URI is an XML namespace. + + This document registers the following YANG module in the "YANG Module + Names" registry [RFC6020]: + + Name: ietf-bfd-unsolicited + + Namespace: urn:ietf:params:xml:ns:yang:ietf-bfd-unsolicited + + Prefix: ietf-bfd-unsolicited + + Reference: RFC YYYY 6. Acknowledgments Authors would like to thank Acee Lindem, Greg Mirsky, Jeffrey Haas and Raj Chetan for their review and valuable input. 7. Security Considerations 7.1. BFD Protocol Security Considerations The same security considerations and protection measures as those described in [RFC5880] and [RFC5881] normatively apply to this document. With "unsolicited BFD" there is potential risk for excessive resource usage by BFD from "unexpected" remote systems. To mitigate such risks, the following measures are mandatory: - o Limit the feature to specific interfaces, and to a single-hop BFD + * Limit the feature to specific interfaces, and to a single-hop BFD with "TTL=255" [RFC5082]. For numbered interfaces source address of an incoming BFD packet should belongs to the subnet of the interface from which the BFD packet is received. For unnumbered interfaces the above check should be aligned with routing protocol addresses running on such pair of interfaces. - o Apply "access control" to allow BFD packets only from certain + * Apply "access control" to allow BFD packets only from certain subnets or hosts. - o Deploy the feature only in certain "trustworthy" environment, + * Deploy the feature only in certain "trustworthy" environment, e.g., at an IXP, or between a provider and its customers. - o Adjust BFD parameters as needed for the particular deployment and + * Adjust BFD parameters as needed for the particular deployment and scale. - o Use BFD authentication. + * Use BFD authentication. 7.2. YANG Module Security Considerations The YANG module specified in this document defines a schema for data that is designed to be accessed via network management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC5246]. @@ -432,32 +448,32 @@ writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations. These are the subtrees and data nodes and their sensitivity/vulnerability: /routing/control-plane-protocols/control-plane-protocol/bfd/ip-sh /unsolicited: - o data node "enable" enables creation of unsolicited BFD IP single- + * data node "enable" enables creation of unsolicited BFD IP single- hop sessions globally, i.e. on all interfaces. See Section 7.1. - o data nodes local-multiplier, desired-min-tx-interval, required- + * data nodes local-multiplier, desired-min-tx-interval, required- min-rx-interval and min-interval all impact the parameters of the unsolicited BFD IP single-hop sessions. /routing/control-plane-protocols/control-plane-protocol/bfd/ip-sh /interfaces/interface/unsolicited: - o data node "enable" enables creation of unsolicited BFD IP single- + * data node "enable" enables creation of unsolicited BFD IP single- hop sessions on a specific interface. See Section 7.1. - o data nodes local-multiplier, desired-min-tx-interval, required- + * data nodes local-multiplier, desired-min-tx-interval, required- min-rx-interval and min-interval all impact the parameters of the unsolicited BFD IP single-hop sessions on the interface. Some of the readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. These are the subtrees and data nodes and their sensitivity/vulnerability: /routing/control-plane-protocols/control-plane-protocol/bfd/ip-sh @@ -465,47 +481,58 @@ the role of the local system in the creation of the unsolicited BFD session. 8. References 8.1. Normative References [I-D.ietf-bfd-yang] Rahman, R., Zheng, L., Jethanandani, M., Pallagatti, S., and G. Mirsky, "YANG Data Model for Bidirectional - Forwarding Detection (BFD)", draft-ietf-bfd-yang-17 (work - in progress), August 2018. + Forwarding Detection (BFD)", Work in Progress, Internet- + Draft, draft-ietf-bfd-yang-17, 2 August 2018, + . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . + [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, + DOI 10.17487/RFC3688, January 2004, + . + [RFC5082] Gill, V., Heasley, J., Meyer, D., Savola, P., Ed., and C. Pignataro, "The Generalized TTL Security Mechanism (GTSM)", RFC 5082, DOI 10.17487/RFC5082, October 2007, . [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/RFC5246, August 2008, . [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, . [RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection (BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881, DOI 10.17487/RFC5881, June 2010, . + [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, . [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration @@ -519,22 +546,24 @@ [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . 8.2. Informative References [I-D.ietf-idr-rs-bfd] Bush, R., Haas, J., Scudder, J. G., Nipper, A., and C. Dietzel, "Making Route Servers Aware of Data Link Failures - at IXPs", draft-ietf-idr-rs-bfd-09 (work in progress), - September 2020. + at IXPs", Work in Progress, Internet-Draft, draft-ietf- + idr-rs-bfd-09, 21 September 2020, + . [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, DOI 10.17487/RFC4271, January 2006, . [RFC7880] Pignataro, C., Ward, D., Akiya, N., Bhatia, M., and S. Pallagatti, "Seamless Bidirectional Forwarding Detection (S-BFD)", RFC 7880, DOI 10.17487/RFC7880, July 2016, . @@ -553,21 +582,22 @@ Enke Chen Palo Alto Networks Email: enchen@paloaltonetworks.com Naiming Shen Zededa Email: naiming@zededa.com + Robert Raszuk NTT Network Innovations 940 Stewart Dr Sunnyvale, CA 94085 - USA + United States of America Email: robert@raszuk.net Reshad Rahman Email: reshad@yahoo.com