Re: ISIS level-2 into level-1 redistribution + filtering

There is an alternate, easily configurable way for filtering. You can
simply set AD=255 (default 115) for routes learned from a IS based on
it's IP address. Those routes will be installed in the ISIS database but
not in the RT so they won't be used for forwarding.
The difference from the "isis tag" method is that R3 will still include
the routes from R2 in it's LSP and the "filtering" is done at R4.
This method it's flexible too since you can match a range of next-hop IP
addresses in the form of IP/wildcard mask and, if you use the
access-list, also match the exact routes you wish to apply the distance
value.

In your case (I suppose that 1.1.1.1 is highest loopback address of R1
included in IS-IS)
R4(config)#router isis
R4(config-router)#distance 255 1.1.1.1 0.0.0.0

To check:
show isis rib
show ip route

Let me know if it worked in your setup.

Eduard

On 31.01.2010 09:45, Service Provider wrote:
> Thanks, so it is not possible to filter ISIS routes based on the Area-ID?
> The only way to achieve this is by IP filtering - cool, thanks.
>
> On Sat, Jan 30, 2010 at 9:29 PM, swap m<ccie19804_at_gmail.com> wrote:
>
>
>> you'll have to match IP prefixes using an ACL/prefix-list or match
>> ISIS route tags to do this filtering.
>> so u need to either use "match ip addr" or "match tag" in the
>> route-map. CLNS matching wont work.
>>
>> isis tags can be set on R1 under the R1's interface using "isis tag
>> <tag-value>" and used on R3 to filter out the tagged routes using a
>> route-map.
>> att-bit is not used for filtering isis ia routes.
>>
>> Swap
>> #19804
>>
>> On Sat, Jan 30, 2010 at 11:04 PM, JR Garcia<ttuner_at_gmail.com> wrote:
>>
>>> try adding "set-attached-bit route-map CLNS" under your ISIS config.
>>> i think that will fix your issue.
>>>
>>>
>>>
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Received on Sun Jan 31 2010 - 12:29:28 ART