Purpose

Purpose of this article is to show how to match based on BGP community under routing peer policy 

How to match community in routing peer policy and take action?

Versa supports regex based community match. Following are some of examples:

Example-1: Match community 7000:101 either in the beginning or end or at middle with NLRI having single or multiple communities

((^|,)7000:101($|,))

Example-2: Match community 7000:101 only at beginning 

((^)7000:101($|,))

Example-3: Match community 7000:101 only at end

((^|,)7000:101($|))

Example-4: Match community 7000:xxxx either in the beginning or end or at middle with NLRI having single or multiple 

((^|,)7000:.*($|,))

Example-5: More complex matches with regex:

((^|,)1000(2|3|4|6|7|8|9|10):(1|3)0000($|,))

((^|,)65185:[1-9]($|,))|((^|,)65185:[1-9][0-9]($|,))|((^|,)65185:[1-9][0-9][0-9]($|,))