Hello,
I have a little concern with PCEP draft. At the end of section 7.3.1 it is said: "If no path computation reply is received from the PCE, and the PCC wishes to resend its request, the same Request-ID-number MUST be used." I'm not sure what is the purpose here. Is it a kind of retransmission process in case no reply is received after N seconds or is it to offer the possibility to the PCC to change the Path Computation constraints? (Actually I guess the intent is the first one, but the draft does not forbid the second case explicitly). In the latter case I think there is a collision case to handle here if the PCC resends the request at the same time the PCE sends the reply for the first request. The PCC cannot know if the reply is for the first request or the second one. In the first case the 2 PathRequests are identical so the problem is less important except that the PCC may receive 2 responses (that may not be identical). Another problem is that if the PathRequest belongs to an SVEC and if there is a collision between a resent PathRequest and the PathReply, the PCE may not remember the SVEC (since it already replied) so the second received PathReply result would not have been performed synchronously with other PathRequests of the SVEC. Wouldn't it be preferable to forbid the reuse of a request id? If a PCC wants to resend a PathRequest it can send a Cancel Request Notification followed by a new PathRequest with a new Id. It seems more straight forward and robust to me. Actually I'm not sure I get the advantage of reusing the same request Id. Best regards Fabien
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