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Versions: 01 02 draft-ryoogray-mpls-tp-psc-itu

Network Working Group                                    A. D'Alessandro
Internet-Draft                                            Telecom Italia
Intended status: Standards Track                                 J. Ryoo
Expires: March 30, 2014                                             ETRI
                                                         H. van Helvoort
                                                     Huawei Technologies
                                                      September 26, 2013


   Supporting the Exercise command for PSC linear protection protocol
                      draft-dj-mpls-tp-exer-psc-02

Abstract

   This draft indicates how IETF RFC6378 could be modified to address
   the Exercise function.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on March 30, 2014.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.



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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Updates to the PSC RFC  . . . . . . . . . . . . . . . . . . .   2
     2.1.  Updates to Section 2.1. Acronyms  . . . . . . . . . . . .   3
     2.2.  Updates to Section 3.1. Local Request Logic . . . . . . .   3
     2.3.  Update to Section 3.2. Remote Requests  . . . . . . . . .   3
     2.4.  Updates to Section 3.6. PSC Control States  . . . . . . .   3
     2.5.  Updates to Section 4.2.2. PSC Request Field . . . . . . .   4
     2.6.  Updates to Section 4.3.2. Priority of Inputs  . . . . . .   4
     2.7.  Updates to Section 4.3.3. Operation of PSC States . . . .   4
       2.7.1.  Updates to Section 4.3.3.1. Normal State  . . . . . .   4
       2.7.2.  Updates to Section 4.3.3.6. Do-not-Revert State . . .   4
       2.7.3.  New subsection for Exercise State . . . . . . . . . .   4
     2.8.  Updates to Appendix A. PSC State Machine Tables . . . . .   6
     2.9.  Updates to Appendix B. Exercising the Protection Domain .   9
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   Exercise is a command to test if the PSC communication is operating
   correctly.  More specifically, the Exercise is to test and validate
   the linear protection mechanism and PSC protocol including the
   aliveness of the Local Request logic, the PSC state machine and the
   PSC message generation and reception, and the integrity of the
   protection path, without triggering the actual traffic switching.  It
   is used while the working path is either carrying the traffic or not.
   It is lower priority than any "real" switch request.  It is only
   valid in bidirectional switching, since this is the only place where
   one can get a meaningful test by looking for a response.

   This command is documented in R84 of [RFC5654] and it has been
   identified as a requirement in the ITU's liaison statement "Liaison
   Statement: Recommendation ITU-T G.8131/Y.1382 revision - Linear
   protection switching for MPLS-TP networks " [LIAISON1205] and
   "Recommendation ITU-T G.8131 revision - Linear protection switching
   for MPLS-TP networks [LIAISON1234].  This draft is created as an
   attempt to align PSC behaviour and functionalities to meet IETF and
   ITU-T MPLS Transport Profile requirements.

2.  Updates to the PSC RFC




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   This section describes the changes required to cover the exercise
   functionality to the PSC protocol defined in [RFC6378]

2.1.  Updates to Section 2.1.  Acronyms

   The following text should be added in Section 2.1 in [RFC6378]:

      EXER Exercise
      RR   Reverse Request

2.2.  Updates to Section 3.1.  Local Request Logic

   EXER should be included as an operator command.

   The following text should be added:

   o  Exercise (EXER) - Exercise is a command to test if the PSC
      communication is operating correctly.  It is lower priority than
      any "real" switch request.  It is only valid in bidirectional
      switching, since this is the only place where one can get a
      meaningful test by looking for a response.

2.3.  Update to Section 3.2.  Remote Requests

   The following text should be added:

   o  Remote EXER - indicates that the remote end point is operating
      under an operator command to validate the protection mechanism and
      PSC protocol including the aliveness of the Local Request logic,
      the PSC state machine and the PSC message generation and
      reception, and the integrity of the protection path, without
      triggering the actual traffic switching.  The valid response to
      EXER message will be an RR with the corresponding FPath and Path
      numbers.  The near end will signal a Reverse Request (RR) only in
      response to an EXER command from the far end.

      When Exercise commands are input at both ends, an EXER, instead of
      RR, is transmitted from both ends.

2.4.  Updates to Section 3.6.  PSC Control States

   The following text should be added:

   o  Exercise state - The operator has issued the Exercise command to
      test and validate the protection mechanism and PSC protocol
      including the integrity of the protection path, without triggering
      the actual traffic switching.




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2.5.  Updates to Section 4.2.2.  PSC Request Field

   The following PSC Requests should be added to PSC Request field:

      (3) Exercise - indicates that the transmitting end point is
      exercising the protection channel and mechanism.  FPath and Path
      are set to the same value of the NR, RR or DNR request that EXER
      replaces.

      (2) Reverse Request - indicates that the transmitting end point is
      responding to an EXER command from the far end.  FPath and Path
      are set to the same value of the NR, RR or DNR request that EXER
      replaces.

2.6.  Updates to Section 4.3.2.  Priority of Inputs

   The priority of the Exercise should be inserted between the
   priorities of WTR Expires and No Request.

2.7.  Updates to Section 4.3.3.  Operation of PSC States

2.7.1.  Updates to Section 4.3.3.1.  Normal State

   Add the following text for Section 4.3.3.1.  Normal State:

   o  A local Exercise input SHALL cause the LER to go into local
      Exercise state and begin transmission of an EXER(0,0) message.

   o  A remote EXER message SHALL cause the LER to go into remote
      Exercise state, and transmit an RR(0,0)message.

2.7.2.  Updates to Section 4.3.3.6.  Do-not-Revert State

   Add the following text for Section 4.3.3.6.  Do-not-Revert State:

   o  A local Exercise input SHALL cause the LER to go into local
      Exercise state and begin transmission of an EXER(0,1) message.

   o  A remote EXER message SHALL cause the LER to go into remote
      Exercise state, and transmit an RR(0,1)message.

2.7.3.  New subsection for Exercise State

   Add a new sub-section, Section 4.3.3.7.  Exercise State, with the
   following text:

   In the Exercise state, the user data traffic SHALL remain on the same
   path as the previous state, such as Normal state or Do-Not-Revert



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   state.  The local end SHALL signal a RR message in response to a
   remote EXER message.  When both ends are in local Exercise state,
   only the EXER messages are exchanged.

   When in Exercise state, the following describe the reaction to local
   input:

   o  A local Clear SHALL be ignored if in remote Exercise state.  If in
      local Exercise state, then this input SHALL cause the LER to go
      into Normal state and being transmitting NR(0,0) when the LER is
      configured for revertive mode.  For non-revertive mode, the LER
      goes into DNR state and begin transmitting DNR(0,1).

   o  A local Lockout of protection input SHALL cause the LER to go into
      local Unavailable state and begin transmission of an LO(0,0)
      message.

   o  A local Forced Switch input SHALL cause the LER to go into local
      Protecting administrative state and begin transmission of an
      FS(1,1) message.

   o  A local Signal Fail indication on the protection path SHALL cause
      the LER to go into local Unavailable state and begin transmission
      of an SF(0,0) message.

   o  A local Signal Fail indication on the working path SHALL cause the
      LER to go into local Protecting failure state and begin
      transmission of an SF(1,1) message.

   o  A local Manual Switch input SHALL cause the LER to go into local
      Protecting administrative state and begin transmission of an
      MS(1,1) message.

   o  A local EXER input can be applied when the local end is in remote
      EXER state.  This SHALL cause the LER to remain in the EXER state,
      but begin transmission of an EXER message instead of RR message.

   o  All other local inputs SHALL be ignored.

   When in Exercise state, the following describe the reaction to remote
   messages:

   o  A remote Lockout of protection message SHALL cause the LER to go
      into remote Unavailable state and begin transmission of an NR(0,0)
      message.






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   o  A remote Forced Switch message SHALL cause the LER to go into
      remote Protecting administrative state and begin transmission of
      an NR(0,1) message.

   o  A remote Signal Fail message for the protection path SHALL cause
      the LER to go into remote Unavailable state and begin transmission
      of an NR(0,0) message.

   o  A remote Signal Fail message for the working path SHALL cause the
      LER to go into remote Protecting failure state and begin
      transmission of an NR(0,1) message.

   o  A remote Manual Switch message SHALL cause the LER to go into
      remote Protecting administrative state and begin transmission of
      an NR(0,1) message.

   o  A remote DNR(0,1) message received in remote Exercise state SHALL
      cause the LER to go into DNR state and begin transmitting
      DNR(0,1).  A remote DNR(0,1) message in local Exercise state is
      ignored.

   o  A remote NR(0,0) message received in remote Exercise state SHALL
      cause the LER to go into Normal state and begin transmitting
      NR(0,0).  A remote NR message in local Exercise state is ignored.

   o  All other local inputs SHALL be ignored.

2.8.  Updates to Appendix A. PSC State Machine Tables

   Add the following extended states:

      E::L = Exercise due to local EXER command
      E::R = Exercise due to remote EXER message

   Add the following messages:

      State REQ(FP, P)
      ----- ----------
      E::L  EXER(0,0)for revertive, or EXER(0,1)for non-revertive
      E::R  RR(0,0) for revertive, or RR(0,1) for non-revertive

   Add the following line to the local inputs describing the table
   description rows:

      EXER   Exercise

   Add the following line to the remote inputs describing the table
   description rows:



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      EXER remote Exercise
      RR   Reverse Request

   Modify the state machine as follows (only relevant cells are shown):

   Part 1: Local input state machine

   +-------+-----+-------+------+------+------+-----+------+------+----+
   |       | OC  | LO    | SF-P | FS   | SF-W | SFc | MS   | WTRE | EX |
   |       |     |       |      |      |      |     |      | xp   | ER |
   +-------+-----+-------+------+------+------+-----+------+------+----+
   | N     |     |       |      |      |      |     |      |      | E: |
   |       |     |       |      |      |      |     |      |      | :L |
   |       |     |       |      |      |      |     |      |      |    |
   | UA:LO |     |       |      |      |      |     |      |      | i  |
   | :L    |     |       |      |      |      |     |      |      |    |
   |       |     |       |      |      |      |     |      |      |    |
   | UA:P: |     |       |      |      |      |     |      |      | i  |
   | L     |     |       |      |      |      |     |      |      |    |
   |       |     |       |      |      |      |     |      |      |    |
   | UA:LO |     |       |      |      |      |     |      |      | i  |
   | :R    |     |       |      |      |      |     |      |      |    |
   |       |     |       |      |      |      |     |      |      |    |
   | UA:P: |     |       |      |      |      |     |      |      | i  |
   | R     |     |       |      |      |      |     |      |      |    |
   |       |     |       |      |      |      |     |      |      |    |
   | PF:W: |     |       |      |      |      |     |      |      | i  |
   | L     |     |       |      |      |      |     |      |      |    |
   |       |     |       |      |      |      |     |      |      |    |
   | PF:W: |     |       |      |      |      |     |      |      | i  |
   | R     |     |       |      |      |      |     |      |      |    |
   |       |     |       |      |      |      |     |      |      |    |
   | PA:F: |     |       |      |      |      |     |      |      | i  |
   | L     |     |       |      |      |      |     |      |      |    |
   |       |     |       |      |      |      |     |      |      |    |
   | PA:M: |     |       |      |      |      |     |      |      | i  |
   | L     |     |       |      |      |      |     |      |      |    |
   |       |     |       |      |      |      |     |      |      |    |
   | PA:F: |     |       |      |      |      |     |      |      | i  |
   | R     |     |       |      |      |      |     |      |      |    |
   |       |     |       |      |      |      |     |      |      |    |
   | PA:M: |     |       |      |      |      |     |      |      | i  |
   | R     |     |       |      |      |      |     |      |      |    |
   |       |     |       |      |      |      |     |      |      |    |
   | WTR   |     |       |      |      |      |     |      |      | i  |
   |       |     |       |      |      |      |     |      |      |    |
   | DNR   |     |       |      |      |      |     |      |      | E: |
   |       |     |       |      |      |      |     |      |      | :L |



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   |       |     |       |      |      |      |     |      |      |    |
   | E::L  | [20 | UA:LO | UA:P | PA:F | PF:W | i   | PA:M | i    | i  |
   |       | ]   | :L    | :L   | :L   | :L   |     | :L   |      |    |
   |       |     |       |      |      |      |     |      |      |    |
   | E::R  | i   | UA:LO | UA:P | PA:F | PF:W | i   | PA:M | i    | E: |
   |       |     | :L    | :L   | :L   | :L   |     | :L   |      | :L |
   +-------+-----+-------+------+------+------+-----+------+------+----+


   Part 2: Remote messages state machine

   +-------+-------+------+------+------+------+-----+----+---+----+---+
   |       | LO    | SF-P | FS   | SF-W | MS   | WTR | DN | N | EX | R |
   |       |       |      |      |      |      |     | R  | R | ER | R |
   +-------+-------+------+------+------+------+-----+----+---+----+---+
   | N     |       |      |      |      |      |     |    |   | E: | i |
   |       |       |      |      |      |      |     |    |   | :R |   |
   |       |       |      |      |      |      |     |    |   |    |   |
   | UA:LO |       |      |      |      |      |     |    |   | i  | i |
   | :L    |       |      |      |      |      |     |    |   |    |   |
   |       |       |      |      |      |      |     |    |   |    |   |
   | UA:P: |       |      |      |      |      |     |    |   | i  | i |
   | L     |       |      |      |      |      |     |    |   |    |   |
   |       |       |      |      |      |      |     |    |   |    |   |
   | UA:LO |       |      |      |      |      |     |    |   | i  | i |
   | :R    |       |      |      |      |      |     |    |   |    |   |
   |       |       |      |      |      |      |     |    |   |    |   |
   | UA:P: |       |      |      |      |      |     |    |   | i  | i |
   | R     |       |      |      |      |      |     |    |   |    |   |
   |       |       |      |      |      |      |     |    |   |    |   |
   | PF:W: |       |      |      |      |      |     |    |   | i  | i |
   | L     |       |      |      |      |      |     |    |   |    |   |
   |       |       |      |      |      |      |     |    |   |    |   |
   | PF:W: |       |      |      |      |      |     |    |   | i  | i |
   | R     |       |      |      |      |      |     |    |   |    |   |
   |       |       |      |      |      |      |     |    |   |    |   |
   | PA:F: |       |      |      |      |      |     |    |   | i  | i |
   | L     |       |      |      |      |      |     |    |   |    |   |
   |       |       |      |      |      |      |     |    |   |    |   |
   | PA:M: |       |      |      |      |      |     |    |   | i  | i |
   | L     |       |      |      |      |      |     |    |   |    |   |
   |       |       |      |      |      |      |     |    |   |    |   |
   | PA:F: |       |      |      |      |      |     |    |   | i  | i |
   | R     |       |      |      |      |      |     |    |   |    |   |
   |       |       |      |      |      |      |     |    |   |    |   |
   | PA:M: |       |      |      |      |      |     |    |   | i  | i |
   | R     |       |      |      |      |      |     |    |   |    |   |
   |       |       |      |      |      |      |     |    |   |    |   |



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   | WTR   |       |      |      |      |      |     |    |   | i  | i |
   |       |       |      |      |      |      |     |    |   |    |   |
   | DNR   |       |      |      |      |      |     |    |   | E: | i |
   |       |       |      |      |      |      |     |    |   | :R |   |
   |       |       |      |      |      |      |     |    |   |    |   |
   | E::L  | UA:LO | UA:P | PA:F | PF:W | PA:M | i   | i  | i | i  | i |
   |       | :R    | :R   | :R   | :R   | :R   |     |    |   |    |   |
   |       |       |      |      |      |      |     |    |   |    |   |
   | E::R  | UA:LO | UA:P | PA:F | PF:W | PA:M | i   | DN | N | i  | i |
   |       | :R    | :R   | :R   | :R   | :R   |     | R  |   |    |   |
   +-------+-------+------+------+------+------+-----+----+---+----+---+


   [20] Transition to N for revertive mode, transition to DNR for non-
   revervtive mode

2.9.  Updates to Appendix B. Exercising the Protection Domain

   Remove Appendix B.

3.  IANA Considerations

   This document makes no request of IANA.

   Note to RFC Editor: this section may be removed on publication as an
   RFC.

4.  Security Considerations

   No specific security issue is raised in addition to those ones
   already documented in [RFC6378]

5.  Acknowledgements

6.  References

6.1.  Normative References

   [RFC5654]  Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N.,
              and S. Ueno, "Requirements of an MPLS Transport Profile",
              RFC 5654, September 2009.

   [RFC6378]  Weingarten, Y., Bryant, S., Osborne, E., Sprecher, N., and
              A. Fulignoli, "MPLS Transport Profile (MPLS-TP) Linear
              Protection", RFC 6378, October 2011.

6.2.  Informative References




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   [LIAISON1205]
              ITU-T SG15, ., "Liaison Statement: Recommendation ITU-T
              G.8131/Y.1382 revision - Linear protection switching for
              MPLS-TP networks ", https://datatracker.ietf.org/liaison/
              1205/ , October 2012.

   [LIAISON1234]
              ITU-T SG15, ., "Liaison Statement: Recommendation ITU-T
              G.8131 revision - Linear protection switching for MPLS-TP
              networks ", https://datatracker.ietf.org/liaison/1234/ ,
              February 2013.

Authors' Addresses

   Alessandro D'Alessandro
   Telecom Italia
   via Reiss Romoli, 274
   Torino  10141
   Italy

   Phone: +30 011 2285887
   Email: alessandro.dalessandro@telecomitalia.it


   Jeong-dong Ryoo
   ETRI
   218 Gajeongno
   Yuseong-gu, Daejeon  305-700
   South Korea

   Phone: +82-42-860-5384
   Email: ryoo@etri.re.kr


   Huub van Helvoort
   Huawei Technologies
   Karspeldreef 4,
   Amsterdam 1101 CJ
   the Netherlands

   Phone: +31 20 4300832
   Email: huub.van.helvoort@huawei.com









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