draft-ietf-bfd-rfc5884-clarifications-01.txt   draft-ietf-bfd-rfc5884-clarifications-02.txt 
Internet Engineering Task Force V. Govindan Internet Engineering Task Force V. Govindan
Internet-Draft Cisco Systems Internet-Draft K. Rajaraman
Updates: 5884 (if approved) K. Rajaraman Updates: 5884 (if approved) Cisco Systems
Intended status: Standards Track G. Mirsky Intended status: Standards Track G. Mirsky
Expires: September 06, 2015 Ericsson Expires: December 18, 2015 Ericsson
N. Akiya N. Akiya
Big Switch Networks
S. Aldrin S. Aldrin
Huawei Technologies Google
March 05, 2015 June 16, 2015
Clarifications to RFC 5884 Clarifications to RFC 5884
draft-ietf-bfd-rfc5884-clarifications-01 draft-ietf-bfd-rfc5884-clarifications-02
Abstract Abstract
This document clarifies the procedures for establishing, maintaining This document clarifies the procedures for establishing, maintaining
and removing multiple, concurrent BFD sessions for a given <MPLS LSP, and removing multiple, concurrent BFD sessions for a given <MPLS LSP,
FEC> described in RFC5884. FEC> described in RFC5884.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
skipping to change at page 1, line 37 skipping to change at page 1, line 38
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." 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 Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 14 skipping to change at page 2, line 15
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Background . . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Background . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. Theory of Operation . . . . . . . . . . . . . . . . . . . . . 3 2. Theory of Operation . . . . . . . . . . . . . . . . . . . . . 3
2.1. Procedures for establishment of multiple BFD sessions . . 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 2.3. Procedures for removing BFD sessions at the egress LSR . 4
2.4. Changing discriminators for a BFD session . . . . . . . . 4 2.4. Changing discriminators for a BFD session . . . . . . . . 4
3. Backwards Compatibility . . . . . . . . . . . . . . . . . . . 4 3. Backwards Compatibility . . . . . . . . . . . . . . . . . . . 5
4. Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
8. Normative References . . . . . . . . . . . . . . . . . . . . 5 8. Normative References . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Background 1. Background
[RFC5884] defines the procedures to bootstrap and maintain BFD [RFC5884] defines the procedures to bootstrap and maintain BFD
skipping to change at page 4, line 4 skipping to change at page 4, line 6
the creation of a BFD session due to policy, it MUST drop the MPLS the creation of a BFD session due to policy, it MUST drop the MPLS
Echo request message. Echo request message.
Ensure the uniqueness of the <MPLS FEC, LSP, Remote Ensure the uniqueness of the <MPLS FEC, LSP, Remote
Discriminiator> tuple. Discriminiator> tuple.
The remaining procedures of session establishment are as specified The remaining procedures of session establishment are as specified
in [RFC5884]. in [RFC5884].
2.2. Procedures for maintenance of multiple BFD sessions 2.2. Procedures for maintenance of multiple BFD sessions
Both the ingress LSR and egress LSR use the YourDiscriminator of the Both the ingress LSR and egress LSR use the YourDiscriminator of the
received BFD packet to demultiplex BFD sessions. received BFD packet to demultiplex BFD sessions.
2.3. Procedures for removing BFD sessions at the egress LSR 2.3. Procedures for removing BFD sessions at the egress LSR
[RFC5884] does not specify an explicit procedure for deleting BFD [RFC5884] does not specify an explicit procedure for deleting BFD
sessions. The procedure for removing a BFD session established by an sessions. The procedure for removing a BFD session established by an
out-of-band discriminator exchange using the MPLS LSP ping can out-of-band discriminator exchange using the MPLS LSP ping can
improve resource management (like memory etc.) especially in improve resource management (like memory etc.) especially in
scenarios involving thousands or more of such sessions. A few 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 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 session transitions from UP to DOWN. This can be done after the
expiry of a configurable timer started after the BFD session state expiry of a configurable timer started after the BFD session state
transitions from UP to DOWN at the egress LSR. transitions from UP to DOWN at the egress LSR.
The BFD session on the egress LSR MAY be removed by the ingress 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 LSR by using the BFD diagnostic code AdminDown(7) as specified in
[RFC5880]. When the ingress LSR wants to remove a session without [RFC5880]. When the ingress LSR wants to remove a session without
triggering any state change at the egress, it MAY transmit BFD triggering any state change at the egress, it MAY transmit BFD
skipping to change at page 4, line 38 skipping to change at page 4, line 41
triggering a change of state. triggering a change of state.
The procedures to be followed at the egress LSR when BFD The procedures to be followed at the egress LSR when BFD
session(s) remain in the DOWN state for a significant amount of session(s) remain in the DOWN state for a significant amount of
time is a local matter. Such procedures are outside the scope of time is a local matter. Such procedures are outside the scope of
this document. this document.
All BFD sessions established with the FEC MUST be removed All BFD sessions established with the FEC MUST be removed
automatically if the FEC is 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 2.4. Changing discriminators for a BFD session
The discriminators of a BFD session established over an MPLS LSP 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 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 removed after a graceful transition to AdminDown state using the BFD
diagnostic code AdminDown. A new session could be established with a diagnostic code AdminDown. A new session could be established with a
different discriminator. The initiation of the transition from the different discriminator. The initiation of the transition from the
Up to Down state can be done either by the ingress LSR or the egress Up to Down state can be done either by the ingress LSR or the egress
LSR. LSR.
skipping to change at page 6, line 17 skipping to change at page 6, line 24
Switched Paths (LSPs)", RFC 5884, June 2010. Switched Paths (LSPs)", RFC 5884, June 2010.
Authors' Addresses Authors' Addresses
Vengada Prasad Govindan Vengada Prasad Govindan
Cisco Systems Cisco Systems
Email: venggovi@cisco.com Email: venggovi@cisco.com
Kalyani Rajaraman Kalyani Rajaraman
Ericsson Cisco Systems
Email: kalyani.rajaraman@ericsson.com Email: kalyanir@cisco.com
Gregory Mirsky Gregory Mirsky
Ericsson Ericsson
Email: gregory.mirsky@ericsson.com Email: gregory.mirsky@ericsson.com
Nobo Akiya Nobo Akiya
Big Switch Networks
Email: nobo.akiya.dev@gmail.com Email: nobo.akiya.dev@gmail.com
Sam Aldrin Sam Aldrin
Huawei Technologies Google
Email: aldrin.ietf@gmail.com Email: aldrin.ietf@gmail.com
 End of changes. 16 change blocks. 
14 lines changed or deleted 23 lines changed or added

This html diff was produced by rfcdiff 1.42. The latest version is available from http://tools.ietf.org/tools/rfcdiff/