ISIS or OSPF as IGP on dual stack core (IPv4 & IPv6)

[schwermie]

Hi all,

I'm working on a design for implementing IPv6 on a backbone network. We are currently using OSPFv2 as our IGP. When we roll out IPv6 we need an IGP with supports IPv6 as well.

There are 2 possible candidates, OSPFv3 and integrated IS-IS. When going for OSPFv3, we have 2 IGP's running at the same time, while IS-IS can handle both IPv4 & IPv6. So IS-IS would save CPU cycles. So far so good.

Now is my question what are other pros / cons for the both IGP's? So i can make a well proposal.

Thanks for all input...

Kind regards,

Marco Hermans

[Harold Ritter]

One thing you should definitely bear in mind when making your decision is the experience your operation ans engineering staff has with OSPF vs ISIS.

Hope this helps,

[Gabriel Farias]

Hello,

We are in the same process in our backbone, I wonder what was the chosen protocol, which the criteria that led to his decision and the lessons learned?

Recards,

Gabriel Farias

[chrihussey]

IS-IS is a great protocol and does not have the have the backbone (Area 0) requirement that OSPF has, which allows for greater flexibility and scales well for large networks.

Depending on how your network operates, if there ever is a requirement to route with different vendor devices, and possibly some Cisco devices too, OSPF will probably be more readily available than IS-IS, which is definitely something to consider.

[Gabriel Farias]

Thank you for answering and revisit this issue, you have a document that can share on this aspect?

I am preparing a proposal to start the study process to start changing the IGP?

[chrihussey]

Sorry, I don't have any specific documents. It's based on my experience working with both protocols.

I  was in a similar situation about a year or so ago and in the end the decision was to go with OSPF considering the network, its size and there was the possibility of having to peer in a multi vendor environment.  OSPF was the safer bet.