Communities

Standard Communities

Informational

BGP Standard Community	AS ingress location
1050:1	Houston, TX
1050:2	Miami, FL
1050:3	Fremont, CA
1050:4	Kansas City, MO

BGP Graceful Shutdown

BGP Standard Community	Description
65535:0	GRACEFUL_SHUTDOWN

We set the local preference to 0 for prefixes marked with this community in accordance with RFC 8326 allowing operators to specifically encourage new paths prior to BGP sessions being disabled deliberately.

Blackhole

BGP Standard Community	Description
1050:666	Blackhole traffic specifically within our AS
65535:666	Generic blackhole instruction

Any prefix received with blackhole communities set automatically have NO_EXPORT applied in compliance with RFC 7999.

Large Communities

Distribution control

BGP Large Community	Description
1050:0:0	Do not announce route to any transit
1050:0:peer-as	Do not announce to peer-as
1050:1:peer-as	Announce route to peer-as

Routes with these communities must still match an approved transit prefix list.

Relation function

BGP Large Community	Description
1050:3:1	Route originated internally
1050:3:2	Route learned from a customer
1050:3:3	Route learned from a peering partner
1050:3:4	Route learned from a transit provider
1050:3:5	Route learned from an IX

ASN-based Selective NO_EXPORT addition

BGP Large Community	Description
1050:4:peer-as	Set NO_EXPORT on routes advertised to peer-as

Adds the well-known NO_EXPORT community to routes advertised to peer-as

Community-based LOCAL_PREF manipulation

BGP Large Community	Description
1050:5:50	Subtract 50 from the default local preference
1050:5:150	Add 50 to the default local preference

RPKI Validation Status

BGP Large Community	Description
1050:1000:1	Prefix is RPKI VALID
1050:1000:2	Prefix is RPKI UNKNOWN
1050:1000:3	Prefix is RPKI NOT CHECKED
1050:1000:4	Prefix is RPKI INVALID

RPKI status communities are not set on updates to any peer. It is considered harmful to manipulate path attributes based on validation state as it potentially introduces harmful large-scale route churn as discussed here. These communities are reserved for looking glass and research purposes.