BGP Communities

This topic shows the BGP communities that can be used to control routing policy. For example, peers can tag their routes to the route servers to adjust the route preference on the network or to control the distribution of advertised prefixes. This can be useful in cases where you want to peer with the entire IX except for one or two specific networks.

You can also filter routes based on a geographic location by specifying a METRO_ID. For a list of IDs, see Metro IDs.

MegaIX route servers support a number of traffic engineering communities to assist peers in controlling route preference and distribution. BGP communities in the range

64990-65512:*

are stripped while all others are passed on to peers.

BGP community values

You can use standard BGP communities to define export policy to peers with 2-byte ASNs, and extended BGP communities for both 2-byte and 4-byte ASN peers.

Standard BGP Community Value Extended BGP Community Value Large BGP Community Value Description
Action
65000:0 rt:65000:0 RS_ASN:65000:0 Do not announce this route to any ASN
65000:ASN rt:65000:ASN RS_ASN:65000:ASN Do not announce this route to ASN
64960:ASN rt:64960:ASN RS_ASN:64960:ASN Do announce this route to ASN if (65000:0) is set
65001:0 rt:65001:0 RS_ASN:65001:0 Prepend peer AS 1 time to all
65001:ASN rt:65001:ASN RS_ASN:65001:ASN Prepend peer AS 1 time to ASN
65002:0 rt:65002:0 RS_ASN:65002:0 Prepend peer AS 2 time to all
65002:ASN rt:65002:ASN RS_ASN:65002:ASN Prepend peer AS 2 time to ASN
65003:0 rt:65003:0 RS_ASN:65003:0 Prepend peer AS 3 time to all
65003:ASN rt:65003:ASN RS_ASN:65003:ASN Prepend peer AS 3 time to ASN
65050:0 rt:65050:0 RS_ASN:65050:0 Do not announce this route to local peers
65050:1 rt:65050:1 RS_ASN:65050:1 Do not announce this route to remote peers
65070:0 rt:65070:0 RS_ASN:65070:0 Do not send this route to any METRO_ID
65070:METRO_ID rt:65070:METRO_ID RS_ASN:65070:METRO_ID Do not send this route to METRO_ID
64970:METRO_ID rt:64970:METRO_ID RS_ASN:64970:METRO_ID Do announce this route to METRO_ID if (64970:0) is set
Informational actions are advertised to the peers on route export:
65040:0 Not used Not used This route comes from a local peer
65040:1 Not used Not used This route comes from a remote peer
65060:METRO_ID Not used Not used This route comes from a peer in METRO_ID

Euro-IX communities

Large communities

BGP Community Value Description
Action
RS_ASN:0:ASN Do not announce this route to ASN
RS_ASN:0:0 Do not announce this route to any ASN
RS_ASN:1:ASN Do announce this route to ASN if (65000:0) is set
RS_ASN:101:0 Prepend peer AS 1 time to all
RS_ASN:101:ASN Prepend peer AS 1 time to ASN
RS_ASN:102:0 Prepend peer AS 2 times to all
RS_ASN:102:ASN Prepend peer AS 2 times to ASN
RS_ASN:103:0 Prepend peer AS 3 times to all
RS_ASN:103:ASN Prepend peer AS 3 times to ASN
Informational actions are advertised to the peers on route export:
RS_ASN:1900:0 This route comes from a local peer
RS_ASN:1900:1 This route comes from a local peer
RS_ASN:1903:METRO_ID This route comes from a peer in METRO_ID

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