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I have a question about making use of SONET level protection in GMPLS. There seem to be conflicting descriptions of how it is handled. I’m particularly interested in the way it is handled for the dedicated 1:1 case. draft-ietf-ccamp-gmpls-recovery-functional-01.txt describes the way it should be handled in signaling and routing as follows
Routing: A single TE link encompassing both working and protection links is announced with Link Protection Type "Dedicated 1:1". If Extra Traffic is supported over the protection link, then the bandwidth parameters for the protection link must also be announced. The differentiation between bandwidth for working and protect links is made using priority mechanisms. In other words, the network must be configured such that bandwidth at priority X or lower is considered Extra Traffic. Signaling: To establish an LSP on the working link, the Link Protection object/TLV indicating "Dedicated 1:1" should be included in the signaling request message for that LSP. To establish an LSP on the protection link, the appropriate priority (indicating Extra Traffic) should be used for that LSP. These objects/TLVs are defined in [GMPLS-SIG]. If the Link Protection object/TLV is not used, link selection is a matter of local policy. This suggests that the working and the protect links are advertised as a single interface in routing and protection object and priority together are used in signaling to identify that extra traffic type protection is requested. If this is true, why do we need “Extra traffic” as a type of protection in signaling and routing as defined in RFC 3471 and draft-ietf-ccamp-gmpls-routing-08.txt. At least it’s not obvious from these documents that one should use a single interface to represent a 1:1 dedicated protection group and use the priority in conjunction with the protection type to identify the ‘extra-traffic’ type protection and also use the priority to describe bandwidth resources on the ‘extra traffic’ link. If that’s the intent, then it would serve well to state that explicitly in the signaling and routing documents. Please apologize and point me to the appropriate sections if that indeed is stated in these documents. Thanks,Karthik |