draft-ietf-mpls-tp-aps-updates-00.txt   draft-ietf-mpls-tp-aps-updates-01.txt 
MPLS Working Group J. Ryoo MPLS Working Group J. Ryoo
Internet-Draft T. Cheung Internet-Draft T. Cheung
Updates: 7271 (if approved) ETRI Updates: 7271 (if approved) ETRI
Intended status: Standards Track H. van Helvoort Intended status: Standards Track H. van Helvoort
Expires: September 20, 2016 Hai Gaoming BV Expires: March 19, 2017 Hai Gaoming BV
I. Busi I. Busi
G. Weng G. Weng
Huawei Technologies Huawei Technologies
March 19, 2016 September 15, 2016
Updates to MPLS Transport Profile (MPLS-TP) Linear Protection in Updates to MPLS Transport Profile (MPLS-TP) Linear Protection in
Automatic Protection Switching (APS) Mode Automatic Protection Switching (APS) Mode
draft-ietf-mpls-tp-aps-updates-00.txt draft-ietf-mpls-tp-aps-updates-01.txt
Abstract Abstract
This document contains updates to MPLS Transport Profile (MPLS-TP) This document contains updates to MPLS Transport Profile (MPLS-TP)
linear protection in Automatic Protection Switching (APS) mode linear protection in Automatic Protection Switching (APS) mode
defined in RFC 7271. The updates provide rules related to the defined in RFC 7271. The updates provide rules related to the
initialization of the Protection State Coordination (PSC) Control initialization of the Protection State Coordination (PSC) Control
Logic, in which the state machine resides, when operating in APS Logic, in which the state machine resides, when operating in APS
mode. mode, and clarify some operation related to state transition table
lookup.
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
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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 20, 2016. This Internet-Draft will expire on March 19, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 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
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 3 2. Conventions Used in This Document . . . . . . . . . . . . . . 3
3. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Updates . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Updates . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. Initialization Behavior . . . . . . . . . . . . . . . . . 4 4.1. Initialization Behavior . . . . . . . . . . . . . . . . . 4
4.2. State Transition Modification . . . . . . . . . . . . . . 5 4.2. State Transition Modification . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 4.3. Operation related to State Transition Table Lookup . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . 6 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . 6 8.1. Normative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 8.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
MPLS Transport Profile (MPLS-TP) linear protection in Automatic MPLS Transport Profile (MPLS-TP) linear protection in Automatic
Protection Switching (APS) mode is defined in RFC 7271 [RFC7271]. It Protection Switching (APS) mode is defined in RFC 7271 [RFC7271]. It
defines a set of alternate and additional mechanisms to perform some defines a set of alternate and additional mechanisms to perform some
of the functions of linear protection described in RFC 6378 of the functions of linear protection described in RFC 6378
[RFC6378]. The actions performed at initialization of the Protection [RFC6378]. The actions performed at initialization of the Protection
State Coordination (PSC) Control Logic are not described in either State Coordination (PSC) Control Logic are not described in either
[RFC7271] or [RFC6378]. Although it is a common perception that the [RFC7271] or [RFC6378]. Although it is a common perception that the
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of [RFC7271]. The changes in the state transition table have been of [RFC7271]. The changes in the state transition table have been
examined to make sure that they do not introduce any new problems. examined to make sure that they do not introduce any new problems.
This document does not introduce backward compatibility issues with This document does not introduce backward compatibility issues with
implementations of [RFC7271]. In case a node implementing this implementations of [RFC7271]. In case a node implementing this
document restarts, the new state changes will not cause problems at document restarts, the new state changes will not cause problems at
the remote node implementing [RFC7271] and the two ends will converge the remote node implementing [RFC7271] and the two ends will converge
to the same local and remote states. In case a node implementing to the same local and remote states. In case a node implementing
[RFC7271] restarts, the two ends behave as today. [RFC7271] restarts, the two ends behave as today.
This document also provides some clarifications on the operation
related to state transition table lookup.
The reader of this document is assumed to be familiar with [RFC7271]. The reader of this document is assumed to be familiar with [RFC7271].
2. Conventions Used in This Document 2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
3. Acronyms 3. Acronyms
This document uses the following acronyms: This document uses the following acronyms:
APS Automatic Protection Switching APS Automatic Protection Switching
DNR Do-not-Revert DNR Do-not-Revert
E::R Exercise state due to remote EXER message E::R Exercise state due to remote EXER message
EXER Exercise EXER Exercise
MS-P Manual Switch to Protection path MS-P Manual Switch to Protection path
MS-W Manual Switch to Working path MS-W Manual Switch to Working path
MPLS-TP MPLS Transport Profile MPLS-TP MPLS Transport Profile
N Normal state N Normal state
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PSC Protection State Coordination PSC Protection State Coordination
RR Reverse Request RR Reverse Request
SD Signal Degrade SD Signal Degrade
SF-P Signal Fail on Protection path SF-P Signal Fail on Protection path
SF-W Signal Fail on Working path SF-W Signal Fail on Working path
UA:P:L Unavailable state due to local SF-P UA:P:L Unavailable state due to local SF-P
WTR Wait-to-Restore WTR Wait-to-Restore
4. Updates 4. Updates
This document updates [RFC7271] by specifying the actions that will This section specifies the actions that will be performed at the
be performed at the initialization of the PSC Control Logic and initialization of the PSC Control Logic and the modifications of the
modifies the state transition table defined in Section 11.2 of state transition table defined in Section 11.2 of [RFC7271]. Some
[RFC7271]. clarifications on the operation related to state transition table
lookup are also provided.
4.1. Initialization Behavior 4.1. Initialization Behavior
This section defines initialization behavior that is not described in This section defines initialization behavior that is not described in
[RFC7271]. [RFC7271].
When the PSC Control Logic is initialized, the following actions MUST When the PSC Control Logic is initialized, the following actions MUST
be performed: be performed:
o Stop the WTR timer if it is running. o Stop the WTR timer if it is running.
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The changes in two rows of remote protecting failure states lead to The changes in two rows of remote protecting failure states lead to
the replacement of note (10) with DNR, therefore note (10) is no the replacement of note (10) with DNR, therefore note (10) is no
longer needed. The resultant three rows read: longer needed. The resultant three rows read:
| MS-W | MS-P | WTR | EXER | RR | DNR | NR | MS-W | MS-P | WTR | EXER | RR | DNR | NR
--------+---------+---------+-----+------+----+------+---- --------+---------+---------+-----+------+----+------+----
N | SA:MW:R | SA:MP:R | (13)| E::R | i | DNR | i N | SA:MW:R | SA:MP:R | (13)| E::R | i | DNR | i
PF:W:R | SA:MW:R | SA:MP:R | (9) | E::R | i | DNR | (11) PF:W:R | SA:MW:R | SA:MP:R | (9) | E::R | i | DNR | (11)
PF:DW:R | SA:MW:R | SA:MP:R | (9) | E::R | i | DNR | (11) PF:DW:R | SA:MW:R | SA:MP:R | (9) | E::R | i | DNR | (11)
4.3. Operation related to State Transition Table Lookup
In addition to the rules related to the state transition table lookup
listed in Section 11 of [RFC7271], the following rule is also applied
to the operation related to the state transition table lookup:
o When the local SF-P is cleared and the priorities of the local and
remote requests are re-evaluated, the last received remote message
may not be valid any more due to the previous failure of the
protection path. Therefore, the last received message MUST be
treated as if it were NR and only the local request shall be
evaluated.
The last paragraph in Section 11 of [RFC7271] is modified as follows:
---------
Old text:
---------
In the state transition tables below, the letter 'i' stands for
"ignore" and is an indication to remain in the current state and
continue transmitting the current PSC message.
---------
New text:
---------
In the state transition tables below, the letter 'i' stands for
"ignore" and the top-priority global request is ignored.
Therefore, the next state can be either the current state
transmitting the current PSC message or the supposed state
(Normal or DNR depending on the footnotes to the state transition
tables) in case of re-evaluation.
5. Security Considerations 5. Security Considerations
No specific security issue is raised in addition to those ones No specific security issue is raised in addition to those ones
already documented in [RFC7271]. It may be noted that tightening the already documented in [RFC7271]. It may be noted that tightening the
description of initializing behavior may help to protect networks description of initializing behavior may help to protect networks
from re-start attacks. from re-start attacks.
6. IANA Considerations 6. IANA Considerations
This document makes no request of IANA. This document makes no request of IANA.
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