--- 1/draft-ietf-bfd-unsolicited-07.txt 2021-11-26 10:13:12.529284675 -0800 +++ 2/draft-ietf-bfd-unsolicited-08.txt 2021-11-26 10:13:12.561285470 -0800 @@ -1,32 +1,36 @@ Network Working Group E. Chen Internet-Draft Palo Alto Networks Intended status: Standards Track N. Shen -Expires: 27 April 2022 Zededa +Expires: 30 May 2022 Zededa R. Raszuk NTT Network Innovations R. Rahman - 24 October 2021 + 26 November 2021 Unsolicited BFD for Sessionless Applications - draft-ietf-bfd-unsolicited-07 + draft-ietf-bfd-unsolicited-08 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). + We also introduce a new YANG module to configure and manage + "unsolicited BFD". The YANG module in this document conforms to the + Network Management Datastore Architecture (NMDA) [RFC8342]. + Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. Status of This Memo @@ -35,54 +39,53 @@ 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 27 April 2022. + This Internet-Draft will expire on 30 May 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. + extracted from this document must include Revised BSD License text as + described in Section 4.e of the Trust Legal Provisions and are + provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Procedures for Unsolicited BFD . . . . . . . . . . . . . . . 3 3. State Variables . . . . . . . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . 10 - 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 8.1. Normative References . . . . . . . . . . . . . . . . . . 11 - 8.2. Informative References . . . . . . . . . . . . . . . . . 12 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 + 4.2. Unsolicited BFD Module . . . . . . . . . . . . . . . . . 6 + 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 + 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10 + 7. Security Considerations . . . . . . . . . . . . . . . . . . . 10 + 7.1. BFD Protocol Security Considerations . . . . . . . . . . 10 + 7.2. YANG Module Security Considerations . . . . . . . . . . . 11 + 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 + 8.1. Normative References . . . . . . . . . . . . . . . . . . 12 + 8.2. Informative References . . . . . . . . . . . . . . . . . 13 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 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. @@ -177,94 +180,116 @@ bfd.UnsolicitedRole The operational mode of BFD interface when configured for unsolicited behaviour. Options can be either PASSIVE, ACTIVE or NULL (NULL - not initialized) for unsolicited BFD sessions. Default (not configured for unsolicited behaviour) MUST be set to NULL if present on the interface. 4. YANG Data Model - This section extends the YANG data model for BFD [I-D.ietf-bfd-yang] - to cover the unsolicited BFD. + This section extends the YANG data model for BFD [RFC9127] to cover + unsolicited BFD. We import [RFC8349] since the "bfd" container in + [RFC9127] is under "control-plane-protocol". 4.1. Unsolicited BFD Hierarchy + Configuration for unsolicited BFD parameters for IP single-hop + sessions can be done at 2 levels: + + * Globally, i.e. for all interfaces. This requires support for the + "unsolicited-params-global" feature. + * For specific interfaces. This requires support for the + "unsolicited-params-per-interface" feature. + + For operational data, a new "unsolicited" container has been added + for BFD IP single-hop sessions. + + The tree diagram below uses the graphical representation of data + models, as defined in [RFC8340]. + module: ietf-bfd-unsolicited augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/bfd:bfd/bfd-ip-sh:ip-sh: +--rw unsolicited {bfd-unsol:unsolicited-params-global}? - +--rw enable? boolean + +--rw enabled? boolean +--rw local-multiplier? multiplier +--rw (interval-config-type)? +--:(tx-rx-intervals) | +--rw desired-min-tx-interval? uint32 | +--rw required-min-rx-interval? uint32 +--:(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:interfaces: +--rw unsolicited {bfd-unsol:unsolicited-params-per-interface}? - +--rw enable? boolean + +--rw enabled boolean +--rw local-multiplier? multiplier +--rw (interval-config-type)? +--:(tx-rx-intervals) | +--rw desired-min-tx-interval? uint32 | +--rw required-min-rx-interval? uint32 +--:(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@2021-10-24.yang" + file "ietf-bfd-unsolicited@2021-11-23.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"; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding Detection + (BFD)"; } import ietf-bfd { prefix "bfd"; - reference "RFC 9127: YANG Data Model for BFD"; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding Detection + (BFD)"; } import ietf-bfd-ip-sh { prefix "bfd-ip-sh"; - reference "RFC 9127: YANG Data Model for BFD"; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding Detection + (BFD)"; } 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. @@ -277,38 +302,44 @@ 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 2021-10-24 { - description "Initial revision."; - reference "RFC YYYY: Unsolicited BFD for Sessionless Applications."; + revision 2021-11-23 { + description + "Initial revision."; + 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."; + reference + "RFC YYYY: Unsolicited BFD for Sessionless Applications."; } feature unsolicited-params-per-interface { description "This feature indicates that the server supports per-interface parameters for unsolicited sessions."; + reference + "RFC YYYY: Unsolicited BFD for Sessionless Applications."; } /* * Type Definitions */ typedef unsolicited-role { type enumeration { enum unsolicited-active { description "Active role"; } @@ -311,56 +342,56 @@ type enumeration { enum unsolicited-active { description "Active role"; } enum unsolicited-passive { description "Passive role"; } } description "Unsolicited role"; } - /* * Augments */ augment "/rt:routing/rt:control-plane-protocols/" + "rt:control-plane-protocol/bfd:bfd/bfd-ip-sh:ip-sh" { + if-feature bfd-unsol:unsolicited-params-global; description "Augmentation for BFD unsolicited parameters"; container unsolicited { - if-feature bfd-unsol:unsolicited-params-global; description "BFD unsolicited top level container"; - leaf enable { + leaf enabled { type boolean; default false; description - "Enable BFD unsolicited globally for IP single-hop."; + "BFD unsolicited enabled globally for IP single-hop."; } uses bfd-types:base-cfg-parms; } } augment "/rt:routing/rt:control-plane-protocols/" + "rt:control-plane-protocol/bfd:bfd/bfd-ip-sh:ip-sh/" + "bfd-ip-sh:interfaces" { + if-feature bfd-unsol:unsolicited-params-per-interface; description "Augmentation for BFD unsolicited on IP single-hop interface"; container unsolicited { - if-feature bfd-unsol:unsolicited-params-per-interface; description "BFD IP single-hop interface unsolicited top level container"; - leaf enable { + leaf enabled { type boolean; default false; - description "Enable BFD unsolicited on this interface."; + description + "BFD unsolicited enabled on this interface."; } uses bfd-types:base-cfg-parms; } } 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" { description "Augmentation for BFD unsolicited on IP single-hop session"; @@ -389,136 +419,123 @@ 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 + Prefix: bfd-unsol 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. + Authors would like to thank Acee Lindem, Greg Mirsky, Jeffrey Haas, + Raj Chetan and Tom Petch 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: * 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 + with "TTL=255" [RFC5082]. For numbered interfaces, the source + address of an incoming BFD packet should belong to the subnet of + the interface on 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. - * Apply "access control" to allow BFD packets only from certain - subnets or hosts. + * Apply "policy" to allow BFD packets only from certain subnets or + hosts. * Deploy the feature only in certain "trustworthy" environment, e.g., at an IXP, or between a provider and its customers. * Adjust BFD parameters as needed for the particular deployment and scale. * 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]. + [RFC8446]. - The NETCONF access control model [RFC6536] provides the means to + The NETCONF access control model [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. There are a number of data nodes defined in this YANG module that are 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: - * data node "enable" enables creation of unsolicited BFD IP single- + * data node "enabled" enables creation of unsolicited BFD IP single- hop sessions globally, i.e. on all interfaces. See Section 7.1. * 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: - * data node "enable" enables creation of unsolicited BFD IP single- + * data node "enabled" enables creation of unsolicited BFD IP single- hop sessions on a specific interface. See Section 7.1. * 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 /sessions/session/unsolicited: access to this information discloses 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)", 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 @@ -528,33 +545,52 @@ [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 - Protocol (NETCONF) Access Control Model", RFC 6536, - DOI 10.17487/RFC6536, March 2012, - . - [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . + [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", + BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, + . + + [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration + Access Control Model", STD 91, RFC 8341, + DOI 10.17487/RFC8341, March 2018, + . + + [RFC8349] Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for + Routing Management (NMDA Version)", RFC 8349, + DOI 10.17487/RFC8349, March 2018, + . + + [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol + Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, + . + + [RFC9127] Rahman, R., Ed., Zheng, L., Ed., Jethanandani, M., Ed., + Pallagatti, S., and G. Mirsky, "YANG Data Model for + Bidirectional Forwarding Detection (BFD)", RFC 9127, + DOI 10.17487/RFC9127, October 2021, + . + 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", Work in Progress, Internet-Draft, draft-ietf- idr-rs-bfd-09, 21 September 2020, . @@ -571,20 +607,25 @@ [RFC7911] Walton, D., Retana, A., Chen, E., and J. Scudder, "Advertisement of Multiple Paths in BGP", RFC 7911, DOI 10.17487/RFC7911, July 2016, . [RFC7947] Jasinska, E., Hilliard, N., Raszuk, R., and N. Bakker, "Internet Exchange BGP Route Server", RFC 7947, DOI 10.17487/RFC7947, September 2016, . + [RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., + and R. Wilton, "Network Management Datastore Architecture + (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018, + . + Authors' Addresses Enke Chen Palo Alto Networks Email: enchen@paloaltonetworks.com Naiming Shen Zededa @@ -582,22 +623,22 @@ 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 United States of America Email: robert@raszuk.net Reshad Rahman + Canada Email: reshad@yahoo.com