Updates to PSC
draft-ietf-mpls-psc-updates-00
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draft-osborne-mpls-psc-updates
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Network Working Group E. Osborne
Internet-Draft Cisco Systems
Intended status: Standards Track October 21, 2013
Expires: April 24, 2014
Updates to PSC
draft-ietf-mpls-psc-updates-00
Abstract
This document contains four updates to the Protection State
Coordination (PSC) logic defined in RFC6378, "MPLS Transport Profile
(MPLS-TP) Linear Protection" . Two of the updates correct existing
behavior. The third clears up a behavior which was not explained in
the RFC, and the fourth adds rules around handling capabilities
mismatches.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
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 April 24, 2014.
Copyright Notice
Copyright (c) 2013 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
Osborne Expires April 24, 2014 [Page 1]
Internet-Draft PSC-updates October 2013
(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
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Incorrect local status after failure . . . . . . . . . . . . 2
3. Reversion deadlock due to a race condition . . . . . . . . . 3
4. Clarifying PSC's behavior in the face of multiple inputs . . 4
5. Handling a capabilities mismatch . . . . . . . . . . . . . . 6
5.1. PT mismatch . . . . . . . . . . . . . . . . . . . . . . . 6
5.2. R mismatch . . . . . . . . . . . . . . . . . . . . . . . 6
5.3. Unsupported modes . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
9.1. Normative References . . . . . . . . . . . . . . . . . . 7
9.2. Informative References . . . . . . . . . . . . . . . . . 8
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
This document contains four updates to PSC [RFC6378]. Three of them
fix issues #2, #7 and #8 as identified in the ITU's liaison statement
"Recommendation ITU-T G.8131/Y.1382 revision - Linear protection
switching for MPLS-TP networks" [LIAISON]. The fourth clears up a
behavior which was not well explained in RFC6378. These updates are
not changes to the protocol's packet format or to PSC's design, but
are corrections and clarifications to specific aspects of the
protocol's procedures.
2. Incorrect local status after failure
Issue #2 in the liaison identifies a case where a strict reading of
RFC6378 leaves a node reporting an inaccurate status:
. A node can end up sending incorrect status - NR(0,1) - despite the
failure of the protection LSP (P-LSP). This is clearly not correct,
as a node should not be sending NR if it has a local failure. To
address this issue, the fourth bullet in section 4.3.3.3 is replaced
with the following three bullets:
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