IGP choice

Mark Tinka mark.tinka at seacom.mu
Fri Oct 23 05:31:08 UTC 2015

On 22/Oct/15 23:22, Bill Blackford wrote:

> I don't have all the details because I don't fully understand it, but
> I've heard that if you're running an MPLS/RSVP core, you can only use
> a single OSPF area. This introduces a scalability ceiling.

Not true.

The rate of development of advanced features in OSPF and IS-IS is at a
similar pace today.

The main issue is implementation. Some vendors will implement the new
capabilities in one protocol sooner than the other. The features may
eventually filter down to the other protocol, or not. It is entirely a
situation specific to your vendor.

For example, IIRC, LFA came to IS-IS in Junos first, and then OSPF
followed (or was it the other way around, I can't remember - but support
didn't come for both immediately). Same thing at Cisco.

Quagga is an example of a case where IS-IS is seriously lagging behind
OSPF to the point of not being useable at all.

So while the spec. will have parity, your choice of vendor will be a
practical factor.


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