Hi WG, We published a new version of the state sync draft which modifies the procedure to "forward" a PCReport onto the state-sync sessions. To ensure that all PCEs always have the latest state and does not override a state by an oldest one that was late on the wire, we propose to rely on the LSP-DB-VERSION used at the PCC side. As a consequence, to have the benefit of state-sync, the PCC must implement the LSP-DB-VERSION.
Feel free to comment the proposed changes. Brgds, -----Original Message----- From: I-D-Announce [mailto:i-d-announce-boun...@ietf.org] On Behalf Of internet-dra...@ietf.org Sent: Monday, August 28, 2017 15:52 To: i-d-annou...@ietf.org Subject: I-D Action: draft-litkowski-pce-state-sync-02.txt A New Internet-Draft is available from the on-line Internet-Drafts directories. Title : Inter Stateful Path Computation Element communication procedures Authors : Stephane Litkowski Siva Sivabalan Dhruv Dhody Filename : draft-litkowski-pce-state-sync-02.txt Pages : 29 Date : 2017-08-28 Abstract: The Path Computation Element Communication Protocol (PCEP) provides mechanisms for Path Computation Elements (PCEs) to perform path computations in response to Path Computation Clients (PCCs) requests. The stateful PCE extensions allow stateful control of Multi-Protocol Label Switching (MPLS) Traffic Engineering Label Switched Paths (TE LSPs) using PCEP. A Path Computation Client (PCC) can synchronize an LSP state information to a Stateful Path Computation Element (PCE). The stateful PCE extension allows a redundancy scenario where a PCC can have redundant PCEP sessions towards multiple PCEs. In such a case, a PCC gives control on a LSP to only a single PCE, and only one PCE is responsible for path computation for this delegated LSP. The document does not state the procedures related to an inter-PCE stateful communication. There are some use cases, where an inter-PCE stateful communication can bring additional resiliency in the design for instance when some PCC-PCE sessions fails. The inter-PCE stateful communication may also provide a faster update of the LSP states when an event occurs. Finally, when, in a redundant PCE scenario, there is a need to compute a set of paths that are part of a group (so there is a dependency between the paths), there may be some cases where the computation of all paths in the group is not handled by the same PCE: this situation is called a split-brain. This split-brain scenario may lead to computation loops between PCEs or suboptimal paths computation. This document describes the procedures to allow a stateful communication between PCEs for various use-cases and also the procedures to prevent computations loops. The IETF datatracker status page for this draft is: https://datatracker.ietf.org/doc/draft-litkowski-pce-state-sync/ There are also htmlized versions available at: https://tools.ietf.org/html/draft-litkowski-pce-state-sync-02 https://datatracker.ietf.org/doc/html/draft-litkowski-pce-state-sync-02 A diff from the previous version is available at: https://www.ietf.org/rfcdiff?url2=draft-litkowski-pce-state-sync-02 Please note that it may take a couple of minutes from the time of submission until the htmlized version and diff are available at tools.ietf.org. Internet-Drafts are also available by anonymous FTP at: ftp://ftp.ietf.org/internet-drafts/ _______________________________________________ I-D-Announce mailing list i-d-annou...@ietf.org https://www.ietf.org/mailman/listinfo/i-d-announce Internet-Draft directories: http://www.ietf.org/shadow.html or ftp://ftp.ietf.org/ietf/1shadow-sites.txt _________________________________________________________________________________________________________________________ Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou privilegiees et ne doivent donc pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce message par erreur, veuillez le signaler a l'expediteur et le detruire ainsi que les pieces jointes. Les messages electroniques etant susceptibles d'alteration, Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci. This message and its attachments may contain confidential or privileged information that may be protected by law; they should not be distributed, used or copied without authorisation. If you have received this email in error, please notify the sender and delete this message and its attachments. As emails may be altered, Orange is not liable for messages that have been modified, changed or falsified. Thank you. _______________________________________________ Pce mailing list Pce@ietf.org https://www.ietf.org/mailman/listinfo/pce
