We use RFC 8092 BGP Large Communities.

Informal Communities:

Community Meaning
- Information X => {
0 = Not specific,
1 = GRA1,
3 = PAR1,
4 = AMS1,
5 = FRA1,
6 = DRO1
}
xx => {
10 = KleyReX,
11 = EVIX,
12 = BFD-IX,
13 = 4IXP,
14 = LL-IX,
15 = TOHU IX,
16 = PyramIX,
17 = OpenSwitch-IX,
18 = HamroIX,
19 = BGP.Exchange
}
213045:X:100 Originated
213045:X:101 Learned from upstreams
213045:X:102 Learned from peers
213045:X:103 Learned from downstreams
213045:X:1xx Learned from IX

Action Communities:

Community Meaning
213045:101:XXX Set local preference (can be 010, 100, 120, 130, 170). Default for customers is 150.
213045:100:666 Blackhole

Remark: We passthrough communities to our upstreams so you can use theirs for more control.