Hi Jan, Thanks for the comments, I think it is really valuable.
For the Double Sided Provisioning model, although the head-end and the tail-end or NMS submit the PCReq message separately, the two reverse lsps can be associated to be optimal if stateful PCE is used. The draft http://datatracker.ietf.org/doc/draft-crabbe-pce-stateful-pce/ just say that all other LSP's condition can be considered if a new request is submitted, however, we want to consider the two related LSPs together (especially the TE parameters), at the same time all the other LSP's condition should be taken into consideration. How about introducing the Association Object in this scenario? When the PCC submits the path computation request for the forward lsp or the backward lsp, the PCReq message may carry association object to indicate that a reverse lsp is needed to be provided later. When the second request with the same Assoication Object arrives, the stateful PCE can compute the two reverse lsps again, and get the optimal path for the associated bi-directional lsp. After the successful computation, the PCE responses the PCC with the PCRep message and updates the reverse lsp with PCUpd Message. Your comments on this are most welcome. Thanks Wenjuan Jan Medved <[email protected]> 2011-10-25 02:21 收件人 "[email protected]" <[email protected]>, "[email protected]" <[email protected]> 抄送 主题 Re: [Pce] [PCE] Request comments on draft-he-pce-pcep-associated-lsp-extensions-00 Hi Wenjuan, Double Sided Provisioning (Section 3.2) will require LSP setup coordination between the head-end and the tail-end, which will need to be provided either by a management system or a stateful PCE proposed in draft-crabbe-pce-stateful-pce-00 ( http://datatracker.ietf.org/doc/draft-crabbe-pce-stateful-pce/). Thanks, Jan On 10/24/11 2:36 AM, "[email protected]<mailto:[email protected] >" <[email protected]<mailto:[email protected]>> wrote: Hi all, 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 computationcan 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. Thanks Wenjuan
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