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.
Personnel
JP Vasseur (jvasseur@cisco.com) is the Document Shepherd.
Adrian Farrel (adrian.farrel@huawei.com) is the Responsible AD.
RFC Editor Note
Section 1.1
Please expand "SRLG" as "Shared Risk Link Group"
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Section 5.1
OLD
If the PCE does not have capability to handle the associated SVEC
objects, it may send a PCErr message with Error-Type="Capability not
supported".
NEW
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".
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Section 5.2
OLD
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.
NEW
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.
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Section 5.3
Please expand "BRPC" as "Backward Recursive Path Computation"