IOS XR Route-policy. Changing route parameters basing on another route?

[wojciechlubas]

Hello,

I would like to make a routing-policy for BGP. My goal is to make an action on path A, while path B appears. Every single operation in route-policy affects only one route or group of routes. For example:

If route A has community 1234:5678 then... "do this or that with Route A"

but what I want to acheive is 

If route A has community 1234:5678 then... "do this or that with Route B"

Is it possible?

[IBMeR]

No. As I understand - RPL evaluate route by route and make decision only based on attributes of route which is evaluating now.

[wojciechlubas]

OK, so maybe in different way.

How to aggregate single /32 routes into bigger subnets without loosing their communities?

[IBMeR]

Yes:)

Try to add "as-set" option of "aggregate-address".

[wojciechlubas]

Cool... but I need it only per neighbor, not globally...

[IBMeR · Accepted solution]

Only by create it globally and filter on all other neighbors.

[wojciechlubas]

I figured out, that this is only one possibility, so I am testing it right now and it works.

Although there are other problems, because I want to separate announcements with communities that are comming from smaller routes and then aggregated, but this I can easy acheive using policies for other neighbors with filtering unwanted communities. More difficult, but at least possible :).