It's a bit non-obvious, but you can do this with a loop. For example we basically replicate the Euro-IX routeserver announcement control communities inside our network, and we use the following function to translate them when exporting routes to a (supporting) route server # Translate Euro-IX common communities for use by a route server function translate_routeserver_communities( int dest_asn ) { lclist announce_controls = filter(bgp_large_community, [(OURAS, 0..1, *)]); for lc c in announce_controls do { bgp_large_community.add((dest_asn, c.data1, c.data2)); } lclist prepends = filter(bgp_large_community, [(OURAS, 101..103, *)]); for lc c in prepends do { bgp_large_community.add((dest_asn, c.data1, c.data2)); } } (I think we could combine those into one with a filter(bgp_large_community, [(OURAS, 0..1, *), (OURAS, 101..103, *)])? This code originally looked slightly different and at the time combining these wasn't posible. Note that this doesn't strip the input communities - we do that as a separate step later where we strip all non-informational communities - Erin On Tue, 20 Feb 2024, at 00:30, Ilham Maulana wrote:
Hi,
Is it possible in bird to copy specific value inside BGP Community?
Example:
Route 1, Community (a,b,*c*) -> inbound Route 2, Community (a,b,*d*) -> inbound -- Route 1, Community (k,l,*c*) -> outbound Route 2, Community (k,l,*d*) -> outbound
The specific value I want to preserve is c and d, and it is dynamic variable.
whatever c and d inbound, copy to c and d outbound.
Thanks. Ilham 5f622eb5-c189-4e05-8584-e4a1d2071a6b