Hi Young. This is a try to resume our discussion started during the SF meeting. Indeed, I still don't get the rationale behind adding the BER as a requirement for PCEP request.
First, I wonder what your intend is when requesting a BER threshold at computation time while you can't really know it before LSP provisioning. Obviously, what we look for is a low BER, but the way I see using BER in routing would be to request a 2nd route *after* a poor BER measurement on a firstly established LSP. Then, considering what you called a "BER estimation", I don't clearly see how you intend to estimate (or model?) it. The BER associated to an LSP is highly dependent on so many parameters: link DGD at measurement time, performance of the FEC used for the to-be-provisioned LSP , possible cross-talk and thus impact of potential adjacent channels... Furthermore, I don't really understand why focusing on the measurable BER range while a typical PMD (in)accuracy may just move us between an acceptable route and an unacceptable one, the latter being the very 1st problem we should try to solve. Finally, I don't get the use of such feature. Even if we could, why would I request a 10^(-6) maximum BER? I don't see any room for anything else than "the best one", so do we really need something else? I tend to see BER as a varying quality feed*back*, not as an indicator that we can accurately target at routing time. I completely agree that PCEP must support optical requirements, but my concern is to understand actual needs before loading the protocol. Therefore, I look forward to reading some clarification on those issues. Best regards, Julien _______________________________________________ Pce mailing list [email protected] https://www.ietf.org/mailman/listinfo/pce
