[c-nsp] IS-IS route separation/filtering

[Oliver Boehmer (oboehmer)]

Jared Gillis <mailto:jared.a.gillis at gmail.com> wrote on Monday, August
10, 2009 21:05:

> Oliver Boehmer (oboehmer) wrote:
>> Well.. not sure how large you want to grow your L1 area, but you
>> could investigate "advertise-passive-only" to only adveritse the
>> loopbacks (all customer routes should be in BGP if you need to plan
>> for growth), and you'll be fine, even with a 1000 nodes in the area.
>> And if you reach this number, address summarization (and the
>> implications of it) will become an issue (even with OSPF)..
>> 
>>> It's looking like we might have to run OSPF on this, but we'd really
>>> rather stick with IS-IS. It seems that OSPF's ability to put
>>> individual interfaces into different areas might be the required
>>> feature that forces us that way. That is, unless anyone knows a way
>>> to put an IS-IS router into different areas aside from assigning
>>> multiple NET addresses...
>> 
>> No, doesn't work with Integrated ISIS (only CLNS allows you to use
>> different ISIS areas on a single node)..
> 
> Hm, I think I may have found my answer in IS-IS Multiarea:
>
http://www.cisco.com/en/US/products/ps6599/products_data_sheet09186a0080
0e9780.html
> 
> I've configured it up in our lab, and running IP IS-IS it seems to do
> exactly what I need.
> I've got my Router A set up running multi-area with one L2 instance
> for backbone and multiple L1 instances for each L1 stub area. The L1
areas only
> see their own internal routes, plus default towards Router A, and I
> have full connectivity from stub to stub.

it might work, but is not supported (as mentioned in the link under
"Restrictions: The IS-IS Multiarea Support feature is supported only for
ISO CLNS.
so use it at your own risk...

	oli