nanog mailing list archives
Re: IGP choice
From: Mark Tinka <mark.tinka () seacom mu>
Date: Fri, 30 Oct 2015 18:43:39 +0200
On 30/Oct/15 15:34, Matthew Petach wrote:
It is rather nice that IS-IS does not require level-2 to be contiguous, unlike area 0 in OSPF. It is a valid topology in IS-IS to have different level-2 areas connected by level-1 areas, though you do have to be somewhat careful about what routes you propagate into-and-back-out-of the intervening level-1 area.
I found Route Leaking in IS-IS to be a moot endeavour because if one wants to keep absolute routing inside the IGP, you'll want to have the core and Loopback interface addresses in the IGP, particularly if you're running an MPLS network. In such a case, the only real gain you get from multi-level IS-IS is a little quietness re: the LSP's being propagated within a particular Level-1 Area. However, things like PRC (Partial Route Calculation) and iSPF (Incremental SPF) help a lot here when you have a flat Level-2 IS-IS domain. Mark.
Current thread:
- Re: IGP choice, (continued)
- Re: IGP choice Bill Blackford (Oct 22)
- Re: IGP choice Mark Tinka (Oct 22)
- Re: IGP choice Saku Ytti (Oct 23)
- Re: IGP choice Mark Tinka (Oct 23)
- Re: IGP choice Saku Ytti (Oct 23)
- Re: IGP choice Mikael Abrahamsson (Oct 23)
- Re: IGP choice Mark Tinka (Oct 23)
- Re: IGP choice marcel.duregards () yahoo fr (Oct 23)
- Re: IGP choice Mark Tinka (Oct 23)
- Re: IGP choice Matthew Petach (Oct 30)
- Re: IGP choice Mark Tinka (Oct 30)
- Re: IGP choice Randy Bush (Oct 24)
- Message not available
- Re: IGP choice Randy Bush (Oct 26)