IPv6: IS-IS or OSPFv3

TJ trejrco at gmail.com
Sat Dec 27 03:15:13 UTC 2008

>I do have some confusion about which one is better for IPv6 in Service
>Provider networks as far as IP routing and MPLS application is concern!

General rule of thumb - use whichever you / your operation is most familiar
	Using IS-IS today, use it for IPv6.
	Using OSPFv2 today, use OSPFv3 for IPv6.

If that isn't good enough for you, then you need to understand the
operational differences between the protocols, and which aspects are most
relevant to your environment.  I can't answer that for you ...

>1. Which protocol should i use to support the IPv6 in network: ISIS or
>    As ISIS has multi-topology feature that can give us capability to run
>IPv4 network separate from IPv6 right! and same thing with OSPF: OSPFv2

Yes, MT could be a benefit ... but "not the same thing" for OSPF.  

>be used for IPv4 routing and OSPFv3 will be used for IPv6 routing! again
>look like resource    utilization for both the protocol will be same as
>are going to use separate database for storing the routing or topology
>information. ISIS still has advantage over OSPF as it does use the TLV
>structure which can help in expanding network to support the new feature!

ISIS is generally considered easier to extend, but OSPF has proven to be
quite extensible itself ... a wash, for the most part.

>2. MPLS is not distributing label for IPv6 protocol so again there will not
>be any IGP best path calcuated for any MPLS related application for IPv6!

Yes, lack of a native IPv6 "control plane" could be something of (cough)

>3. what if i have already running OSPFv2 for IPv4 in the network then
>i think for migrating to ISIS?
>   if yes then what are the advantages that I can look at for migrating my
>network to IS-IS?

Again, IMHO this depends on way too many factors to make a simple, blanket

>Devang Patel


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