--- 1/draft-ietf-bfd-rfc5884-clarifications-01.txt 2015-06-16 08:15:40.914399441 -0700 +++ 2/draft-ietf-bfd-rfc5884-clarifications-02.txt 2015-06-16 08:15:40.934399924 -0700 @@ -1,23 +1,24 @@ Internet Engineering Task Force V. Govindan -Internet-Draft Cisco Systems -Updates: 5884 (if approved) K. Rajaraman +Internet-Draft K. Rajaraman +Updates: 5884 (if approved) Cisco Systems Intended status: Standards Track G. Mirsky -Expires: September 06, 2015 Ericsson +Expires: December 18, 2015 Ericsson N. Akiya + Big Switch Networks S. Aldrin - Huawei Technologies - March 05, 2015 + Google + June 16, 2015 Clarifications to RFC 5884 - draft-ietf-bfd-rfc5884-clarifications-01 + draft-ietf-bfd-rfc5884-clarifications-02 Abstract This document clarifies the procedures for establishing, maintaining and removing multiple, concurrent BFD sessions for a given described in RFC5884. Status of This Memo This Internet-Draft is submitted in full conformance with the @@ -26,21 +27,21 @@ 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 September 06, 2015. + This Internet-Draft will expire on December 18, 2015. Copyright Notice Copyright (c) 2015 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 @@ -49,24 +50,24 @@ 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. Background . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 2. Theory of Operation . . . . . . . . . . . . . . . . . . . . . 3 2.1. Procedures for establishment of multiple BFD sessions . . 3 - 2.2. Procedures for maintenance of multiple BFD sessions . . . 3 + 2.2. Procedures for maintenance of multiple BFD sessions . . . 4 2.3. Procedures for removing BFD sessions at the egress LSR . 4 2.4. Changing discriminators for a BFD session . . . . . . . . 4 - 3. Backwards Compatibility . . . . . . . . . . . . . . . . . . . 4 + 3. Backwards Compatibility . . . . . . . . . . . . . . . . . . . 5 4. Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 8. Normative References . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 1. Background [RFC5884] defines the procedures to bootstrap and maintain BFD @@ -143,21 +145,21 @@ Both the ingress LSR and egress LSR use the YourDiscriminator of the received BFD packet to demultiplex BFD sessions. 2.3. Procedures for removing BFD sessions at the egress LSR [RFC5884] does not specify an explicit procedure for deleting BFD sessions. The procedure for removing a BFD session established by an out-of-band discriminator exchange using the MPLS LSP ping can improve resource management (like memory etc.) especially in scenarios involving thousands or more of such sessions. A few - options are possible here: + observations are made here: The BFD session MAY be removed in the egress LSR if the BFD session transitions from UP to DOWN. This can be done after the expiry of a configurable timer started after the BFD session state transitions from UP to DOWN at the egress LSR. The BFD session on the egress LSR MAY be removed by the ingress LSR by using the BFD diagnostic code AdminDown(7) as specified in [RFC5880]. When the ingress LSR wants to remove a session without triggering any state change at the egress, it MAY transmit BFD @@ -167,20 +169,26 @@ triggering a change of state. The procedures to be followed at the egress LSR when BFD session(s) remain in the DOWN state for a significant amount of time is a local matter. Such procedures are outside the scope of this document. All BFD sessions established with the FEC MUST be removed automatically if the FEC is removed. + The egress MUST use the discriminators exchanged when the session + was brought UP, to indicate any session state change to the + ingress. The egress SHOULD reset this to zero after transmitting + bfd.detectMult number of packets if the BFD session transitions to + DOWN state. + 2.4. Changing discriminators for a BFD session The discriminators of a BFD session established over an MPLS LSP cannot be changed when it is in UP state. The BFD session could be removed after a graceful transition to AdminDown state using the BFD diagnostic code AdminDown. A new session could be established with a different discriminator. The initiation of the transition from the Up to Down state can be done either by the ingress LSR or the egress LSR. @@ -239,27 +247,28 @@ Switched Paths (LSPs)", RFC 5884, June 2010. Authors' Addresses Vengada Prasad Govindan Cisco Systems Email: venggovi@cisco.com Kalyani Rajaraman - Ericsson + Cisco Systems - Email: kalyani.rajaraman@ericsson.com + Email: kalyanir@cisco.com Gregory Mirsky Ericsson Email: gregory.mirsky@ericsson.com Nobo Akiya + Big Switch Networks Email: nobo.akiya.dev@gmail.com Sam Aldrin - Huawei Technologies + Google Email: aldrin.ietf@gmail.com