changing BGP filter-list without downtime

[mpauls]

Hello,

I have several (about 40) BGP peers to which I applied a simple filter-list just like this:

neighbor 10.20.30.40 filter-list 10 out

ip as-path access-list 10 permit ^$

ip as-path access-list 10 permit 12345

so that to 10.20.30.40 only prefixes from our own AS and from AS12345 are advertised.

Now I created a second access-list 11 that only contains our own AS without AS12345.

When I bind this new access-list to any peer, the routes advertised to this peer disappear for

about 20 seconds and the BGP session seems interrupted. Afterwards it reestablishes and

all works exactly like planned - only prefixes originated in our AS are advertised to this peer.

Is there a way to change the advertising prefixes with the filter-list in a "soft" way without

any downtime to the specific peer?

Best regards,

Marc.

[dbeattie]

You could try putting the filter-list into a route-map construct. One route-map statement for each filter-list. This should allow you to change the route-map. You may need to use soft reconfig outbound, depending upon your device type.

Hope this helps,

Dave