Updates to PSC
draft-ietf-mpls-psc-updates-00
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
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provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on April 24, 2014.
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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Internet-Draft PSC-updates October 2013
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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:
Osborne Expires April 24, 2014 [Page 2]
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o If the current state is due to a local or remote Manual Switch, a
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