Re: encoding link id for unnumbered interfaces

[Yakov Rekhter <yakov@juniper.net>]

> Yakov,
> 
> -> I'd like to suggest that we replace Link Local Identifier sub-TLV
> -> and Link Remote Identifier sub-TLV (in both ISIS and OSPF) with a
> -> single sub-TLV that would contain both Link Local Identifier and Link 
> -> Remote Identifier.
> 
> -> Any objections ?
> 
>   I prefer : different sub-TLVs. That gives consistency and
>              easy modification in future.
> 
>   I suggest: Rather make Remote Identifier *mandatory* when
>              Local Identifier is present. This is definitely
>              bad but little better than your suggestion. :-)
> 
>   I like   : Make both Local and Remote Identifiers are optional
>              (just like local and remote IP address TLVs in TE)
>              and leave the decision to individual vendors 
>              (local decision). 
> 
>   Is there any scenario where this causes interop issues?!?!
>   Is that you are worried about *Tag, Length* extra memory
>   consumption?

No, it is just that if you have both local and remote identifiers
in the same sub-TLV, you don't have to worry about such error
cases as the situation where you have remote identifier sub-TLV
present, but the local identifier sub-TLV missing.

Yakov.

P.S. In contrast with numbered interfaces that allow for both
p2p and multiaccess interfaces, unnumbered interfaces are
restricted to p2p only.