The MPLS WG Archive

[Alex Zinin <azinin@cisco.com>]

Thomas,

>>Note too that the interface index cannot be made bigger than 2^24;
>>this is so that the distinction between IP addresses and interface
>>indices is clear.  Given that, and given the fact the SNMP ifIndexes
>>can be 32 bits, ifIndexes are ruled out as potential interface
>>indices.

>          Personally, this seems like a flaw in the design. The type
> ifIndex has been around for quite a long time. I don't see how
> the ifIndex in OSPF/ISIS was allowed to use a different size
> while claiming that one could put use an ifIndex from the Interfaces
> MIB.

I don't want confusion here, so let's clarify a bit.

ifIndex is 32-bit, so is the Link Data field in OSPF router-LSA.
So OSPF is fine, actually. You won't find "IfIndex" in ISIS
spec :)

But in fact we're not much concerned about legacy OSPF/ISIS,
we should be talking about TE extensions. And they also use 32 bits.
So, the size is fine again :)

Alex.