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

[Jared Gillis]

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_sheet09186a00800e9780.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.

> 
> 	oli