Routing

Hi All,

   I have two routers which are peered via IBGP.  One router has many routes with route tags on them.  When the routes get sent to the other router via IBGP the tags get removed.  Is there a way that I can keep my tags across the IBGP session?

Thanks

Bgp communities should be advertised to ibgp neighbors by default.  Do you have any import/export policies applied to the neighbors or groups?

Ben

Yes I have a basic policy applied to export my routes through IBGP.  If I try to add a community i get an error saying the community is not reference in the bgp config.

Do you have an example of how I could configure a comunity and apply it as a tag to one of my routes I am advertising out to BGP.

Thanks!

You must define the community, and reference it by community-name in the policy.  Here is an example that matches the 10.0.0.0/24 prefix, and then sets a community named "customer", which is defined as 65001:1234. 

policy-options {
    policy-statement add-community {
        term term1 {
            from {
                route-filter 10.0.0.0/24 exact;
            }
            then {
                community set customers;
                accept;
            }
        }
    }
    community customers members 65000:1234;
}

There are a three community action options.  They are defined as:

community (+ | add) [ names ]: (BGP only) Add the specified communities to the set of communities in the route.
community (- | delete) [ names ]: (BGP only) Delete the specified communities from the set of communities in the route.
community (= | set) [ names ]: (BGP only) Replace any communities that were in the route in with the specified communities.

A few Junos documentation links regarding bgp communities and policy.

http://www.juniper.net/techpubs/en_US/junos10.3/topics/concept/policy-bgp-communities-extended-communities-match-conditions-overview.html

http://www.juniper.net/techpubs/en_US/junos10.3/topics/concept/policy-bgp-communities-extended-communities-evaluation-in-routing-policy-match-conditions.html

Hi Benb,

   Thanks alot this information was great.  I can use the communities to do what I want.  Just one question though, I am able to set the community through a policy map like the example you showed but in one of the links I read that you can apply communities to non-bgp routes.  I would need to do this to some of my static routes.  I cant seem to be able to add the community tag to any of them, i keep getting this error.

under policy options i have

community test members 65000:1234;

Then uder routing options i try to do this

______________

set static route 66.66.66.66 next-hop 1.1.1.1 community [test]
                                                               
invalid community.

Or

set static route 66.66.66.66 reject community [1234]
                                                                ^
invalid community.

any idea why?

Thanks

Hi

I guess the format of the community should be  [AS_number:community_number]

BR

Abubaker