> Hi all, Hi,
> We've submitted a draft for the extensions of PCEP to support > associated bidirectional lsp, below is the link: > http://tools.ietf.org/html/draft-he-pce-pcep-associated-lsp-extensions-00. > The MPLS-TP requirements [RFC5654] and control plane framework documents > [RFC6373]describe that MPLS-TP MUST support associated bidirectional > point-to-point LSPs. Path Computation Element (PCE), see [RFC4655], > may be used for path computation of a GMPLS LSP,and consequently an > associated bidirectional LSP, across domains and in a single domain. > As described in http://tools.ietf.org/html/ > draft-ietf-ccamp-mpls-tp-rsvpte-ext-associated-lsp-02, the associated > bidirectional LSP can be deployed by Single Sided Provisioning model or > Double Sided Provisioning model.For the double sided provisioning, the > path computation of the forward and the backward LSP are submitted by > the head-end and the tail-end separately.For the single sided > provisioning, the path computation can be realized by the concurrent or > successive computation. The concurrent computation means that the > head-end submits the computation request for both two directional LSPs > concurrently. As to the successive computation, the head-end and the > tail-end send the forward LSP and backward LSP computation requests > separately. > > We have extended PCEP protocol to support the Concurrent computation > for Single Sided Provisioning model. Concurrent computation can ensure > that the paths for the associated bidirectional LSP is optimal, as > described in > http://tools.ietf.org/html/rfc5557. > In this draft, an A-bit is added to the flag bits of the RP object to > indicate the request is about an associated bidirectional LSP or not. > futhermore,REVERSE_LSP object is added in a PCReq message to specify the > information of the reverse LSP. > > Please provide comments and feedback. Hi, According to [RFC5654], "Associated bidirectional path: A path that supports traffic flow in both directions but that is constructed from a pair of unidirectional paths (one for each direction) that are associated with one another at the path's ingress/egress points. The forward and backward directions are setup, monitored, and protected independently. As a consequence, they may or may not follow the same route (links and nodes) across the network." >From PCEP protocol point the Concurrent computation for Single Sided Provisioning model can be achieved with the following options: - SVEC request containing one request for the forward direction and one request for the reverse direction (forward and reverse path MAY be different) - One bidirectional request using GENERALIZED-BANDWIDTH with forward and reverse bandwidth if both direction must follow the same path and have same other properties This cover the requirements you are describing, I do not see the need for PCEP extensions. One thing that could be considered (As far as I remember it was also raised for backup ingress and egress draft) is that the SVEC only allows to compute diverse route but there is no indication that one desire sharing of links, node (SRLGS?) for synchronized requests. BR > > Thanks > Wenjuan _______________________________________________ Pce mailing list [email protected] https://www.ietf.org/mailman/listinfo/pce
