Using BGP communities to influence routing
Some free time here in Europe and thus time for another quick blog post & to take my mind away from depressing people!
One of impressive features of major European networks is support for BGP communities. In India it’s almost non-existent. Setting it up isn’t hard technically but from capacity management side, Indian ISPs are somewhat shy in setting it up.
Let’s put a case where we have a Customer router (R1 with AS1), upstream of customer (R2 with AS2), upstream of upstream (R3 with AS3), peer of upstream (R4 with router4). Let’s try to setup communities so that customer at AS1 can control his BGP announcements and announce some prefixes to AS3 and some to AS4 selectively to control inbound traffic flow.