Re: Comments on draft-shen-isis-extended-tlv-00.txt
Naiming Shen <naiming <at> redback.com>
2004-08-05 23:35:41 GMT
] A few comments I raised at the mic today:
] 1. One of the reasons that was mention was exhaustion of the TLV type
] space. Given that we have only 36 allocations in the registry now,
] I doubt this will be a problem any time soon.
Agreed. But this code point is a side effect of the draft. I think anyone
would agree that if we take the trouble to change the length field,
the code field better to be changed at the same time.
] 2. Another reason was the size of the TLV. If this becomes a problem,
] my first question would be whether this is a good idea to announce
] such info in ISIS and/or whether it is properly encoded. This is not
] to say that we could never end up with having to announce something
] bigger than 255, but I'd like to see an example of where this becomes
] a problem we can't get around.
Ok, let me list some of the reasoning here, others can contribute too,
- network transition is not easy, it can takes years to finish, for
all the boxes converge into the same capabilities.
- a pure historical note: at the time we desgined the Multi-Topology
IS-IS, there was a choice to use the existing TLV 22 and 135. But the
major concern at the time was if there were multiple topologies using
TE (not even talking about GMPLS), then the 255 bytes of the TLV would