[112323] in North American Network Operators' Group
RE: ISIS route summarization
daemon@ATHENA.MIT.EDU (Ivan Pepelnjak)
Tue Feb 24 05:01:07 2009
From: "Ivan Pepelnjak" <ip@ioshints.info>
To: "'Jack Bates'" <jbates@brightok.net>,
<nanog@nanog.org>
Date: Tue, 24 Feb 2009 11:00:44 +0100
In-Reply-To: <49A3146E.30106@brightok.net>
Errors-To: nanog-bounces@nanog.org
The short answer is "NO". L2 IS-IS is a single SPF domain and all routers
are supposed to have identical view of the network. If you want
IS-IS-provided aggregation, you need to use L1 and L2.
There are only two protocols that allow unlimited levels of aggregation: BGP
and EIGRP :)
Ivan
http://www.ioshints.info/about
http://blog.ioshints.info/
> -----Original Message-----
> From: Jack Bates [mailto:jbates@brightok.net]
> Sent: Monday, February 23, 2009 10:26 PM
> To: nanog@nanog.org
> Subject: ISIS route summarization
>
> In a level2 only ISIS network (not using multiple areas due
> to MPLS limitations), is there a better method for handling
> aggregate routes than creating an aggregate and
> redistributing it into ISIS for each router? Primarily
> Cisco/Juniper based. Cisco I believe has an aggregate option
> in ISIS (similar to OSPF) and Juniper has a separate
> aggregate function which can be distributed into ISIS.
> Neither can do summarization per say unless they cross
> between levels; unless I'm mistaken.
>
> Offlist input is fine. Just trying to double check my brain
> while setting up IPv6 on the access edges.
>
> Link state does have it's limitations. ;)
>
>
> -Jack
>
>
>
