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Version 5.3.0, 2014-04-12
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Use of the Synchronization VECtor (SVEC) List for Synchronized Dependent Path Computations

Approval Announcement

Draft of message to be sent after approval:

From: The IESG <>
To: IETF-Announce <>
Cc: Internet Architecture Board <>,
    RFC Editor <>, 
    pce mailing list <>, 
    pce chair <>
Subject: Document Action: 'The use of SVEC (Synchronization VECtor) list for Synchronized dependent path computations' to Informational RFC

The IESG has approved the following document:

- 'The use of SVEC (Synchronization VECtor) list for Synchronized 
   dependent path computations '
   <draft-ietf-pce-pcep-svec-list-05.txt> as an Informational RFC

This document is the product of the Path Computation Element Working Group. 

The IESG contact persons are Adrian Farrel and Stewart Bryant.

A URL of this Internet-Draft is:
Technical Summary

   A Path Computation Element (PCE) performing dependent path
   computations, for instance calculating a diverse working and
   protected path not sharing common network points, would need to
   synchronize the computations in order to increase the probability of
   meeting the working and protected path diversity (or disjointness)
   objective and network resource optimization objective. When a PCE
   computes multiple sets of dependent path computation requests
   concurrently, it is required to use Synchronization VECtor (SVEC)
   list for association among the sets of dependent path computation
   requests. SVEC is also applicable to end-to-end diverse path
   computation across multiple domains. This document describes the
   usage of SVECs in the SVEC list and diverse path computation
   guideline, for the synchronized computation of dependent paths.

Working Group Summary

   No controversy.

Document Quality

   This document is informational, explaining the detail of existing
   protocol mechanisms to achieve specific functions. There is at
   least one implementation that we are aware of that makes use of
   the mechanisms described here.


   JP Vasseur ( is the Document Shepherd.
   Adrian Farrel ( is the Responsible AD.

RFC Editor Note

Section 1.1
Please expand "SRLG" as "Shared Risk Link Group"
Section 5.1
   If the PCE does not have capability to handle the associated SVEC 
   objects, it may send a PCErr message with Error-Type="Capability not 
   If the PCE, which is unable to handle the associated SVEC, finds 
   the common request-IDs in multiple SVEC objects, the PCE should
   cancel the path computation request and respond to the PCC with
   the PCErr message Error-Type="Capability not supported".
Section 5.2
   If a PCC sends path computation requests to a PCE and then sends 
   another path computation requests, which are dependent on the first 
   requests and has been associated by using a SVEC list.
   However, if a PCC sends path computation requests to a PCE, and then 
   sends a further path computation request to a different PCE using the 
   SVEC list to show that the further request is dependent on the first 
   requests, there is no method for the PCE to correlate the dependent 
   requests sent to different PCEs.
Section 5.3
Please expand "BRPC" as "Backward Recursive Path Computation"