Use of the Synchronization VECtor (SVEC) List for Synchronized Dependent Path Computations
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From: The IESG <firstname.lastname@example.org> To: IETF-Announce <email@example.com> Cc: Internet Architecture Board <firstname.lastname@example.org>, RFC Editor <email@example.com>, pce mailing list <firstname.lastname@example.org>, pce chair <email@example.com> 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: http://www.ietf.org/internet-drafts/draft-ietf-pce-pcep-svec-list-05.txt
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 (firstname.lastname@example.org) is the Document Shepherd. Adrian Farrel (email@example.com) is the Responsible AD. RFC Editor Note Section 1.1 Please expand "SRLG" as "Shared Risk Link Group" --- 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". --- 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. --- Section 5.3 Please expand "BRPC" as "Backward Recursive Path Computation"