SDH and EoSDH networks are widely used by Portugal Telecom Comunicacoes (PTC) and TMN (respectively the incumbent operator in Portugal and PT group's mobile operator), as well as foreign PT's clients (Brazilian "Vivo", for instance). These operators are used to both SDH and Ethernet's OAM paradigm. We ask you therefore to consider that MPLS-TP OAM protocols MUST allow equivalent OAM mechanisms.
Being more precise, we would like to use the same protocol messages, to give/have the same "touch&feel" we had in SDH and for less time in ETH. In SDH... -it allows you at each end to check you have signal reception and notify the other end when you don't (RDI) -it does so at different levels (in SDH you can have it both for each VC and for the STM) -it has a means by which to exchange an APS protocol In ETH... -we've been using Y.1731 in EoSDH systems; it was the ITU standard developed for this purpose and was thought in the same principles stated for SDH; the most logical evolution would hence be to use the same PDUs and mechanisms as faithfully as possible with an adequate MPLS-TP encapsulation -MEF defined performance monitoring functions for frame loss measurement [FL], delay measurement, delay variation measurement, which are also addressed in Y.1731 The main reason to use the same PDUs as in Y.1731 is probably the same i guess and respect in RFC5654 2nd general requirements: economy. We can't though forget this requirement list will have impact on ITU standards and that, although much of the work in MPLS-TP is IETF's merit and sweat, probably no one would need it if ITU didn't start T-MPLS (whose interoperability problems with MPLS/IP were afterwards pointed out by IETF and originated all the work we can see now). I would also like to point out that the mechanisms in Y.1731 are sufficiently simple to allow some "hardwarization", which would ease more vendor's implementations to converge to the 50ms protection timescale, allowing a way to do this in a cheaper, more scalable and miniaturized way. Thank You for your time. Best Regards, Rui Costa _______________________________________________ Ietf mailing list Ietf@ietf.org https://www.ietf.org/mailman/listinfo/ietf
