BGP Communities

Use Border Gateway Protocol (BGP) communities to control BGP traffic.

Learn more about our network

Informational Communities

Informational Communities convey how and where a route was learned by our network.

They always have 5 digits in the second half and use the following structure:

23352:TCRPP

T – The type of relationship through which the route was learned.
C – The continent in which the route was learned.
R – The region of the continent in which the route was learned.
PP – The POP city code in which the route was learned.

VALUERELATIONSHIPCONTINENTREGION
0AllAll
1TransitNorth AmericaNorth-West
2Public PeerEuropeNorth
3Private PeerAsiaNorth-East
4CustomerAustraliaWest
5InternetSouth AmericaCentral
6AfricaEast
7Middle EastSouth-West
8South
9South-East

 

CITY CODECITY/POP IDENTIFIERCITY STATE/PROVINCE, COUNTRY
11IADAshburn VA, United States
12NYCNew York NY, United States
13SJCSan Jose CA, United States
14PAOPalo Alto CA, United States
15SFOSan Francisco CA, United States
16ORDChicago IL, United States
17DFWDallas/Forth Worth TX, United States
18LAXLos Angeles CA, United States
19EWRNewark NJ, United States
20AMSAmsterdam, Netherlands
21TKOTokyo, Japan
22LHRLondon, United Kingdom
23ATLAtlanta GA, United States
24PHXPhoenix AZ, United States
25MTLMontreal QC, Canada
26TORToronto ON, Canada
27IAHHouston TX, United States
28SEASeattle WA, United States
29DENDenver CO, United States
30MIAMiami FL, United States
31SLCSalt Lake City UT, United States
32FRAFrankfurt, Germany
33CDGParis, France
34BOSBoston MA, United States
35ROTSt Leon-Rot, Baden-Württemberg, Germany
36OTPBucharest, Romania
41SYDSydney, New South Wales, Australia
55GRUSão Paulo, Sa Região Sudeste, Brazil

Action Communities

Action Communities are optional communities for controlling route attributes and how they’re exported to other networks.

Action Communities can be targeted to specific peer ASNs, locations (by continent, region, city), or classes of neighbors (transits, peers, customers). They always have 4 digits in the second half and use the following structure:

ASN:A0CR or ASN:A1PP

A – The action code to be performed
C – The target continent
R – The target region
PP – The target POP city code

ACTION CODEACTION
1Prepend AS-PATH with 23352 on export
2Prepend AS-PATH with 23352 23352 on export
3Prepend AS-PATH with 23352 23352 23352 on export
4Prepend AS-PATH with 23352 23352 23352 23352 on export
5Set Multi-Exit Discriminator (MED) to 0 on export
6Do not export
9Override a Do Not Export (action code 6)

 

TARGET ASNMEANING
23352Apply action to all neighbor ASNs
#####Apply action to a specific ASN #####
65001Apply action to all Transits
65002Apply action to all Peers
65003Apply action to all Customers

 

How do I use Action Community tags with multiple criteria?
COMMUNITYMEANING
23352:1000Prepend once to all BGP neighbors globally
23352:2010Prepend twice to all BGP neighbors in North America
23352:3111Prepend three times to all BGP neighbors in Ashburn, VA
3549:6000Do not export to AS3549/Global Crossing globally
65001:6020Do not export to any IP Transit neighbors in Europe

 

Local Preference Communities

Local Preference Communities are values that influence the best-path selection of BGP prefixes. The local-preference attribute only applies to path selection within ServerCentral’s network. A value of 50 will create a backup route that’s neither used nor propagated to the rest of the Internet, only becoming active if no other route is heard.

 

COMMUNITYLOCAL PREFERENCE SETTING
NOTES
23352:50Set local-preference to 50Backup route only
23352:100Set local-preference to 100Default transit route
23352:150Set local-preference to 150Less than peer, more than transit
23352:200Set local-preference to 200Default peer route
23352:250Set local-preference to 250Less than customer, more than peer
23352:300Set local-preference to 300Default customer route
23352:350Set local-preference to 350Preferred above other customers

Other Communities

These miscellaneous communities don’t fit in any other format.

 

COMMUNITYMEANING
23352:69Multihomed Customer Advisory Tag (this is used to automatically indicate any known issues, such as congestion or routing problems, so that multi-homed customers can match this community and divert traffic to another path)
23352:666Null route all traffic to this prefix (requires a pre-established session with a BGP blackhole server)
23352:998Within the ServerCentral network, do not export the prefix outside of the current continent
23352:999Within the ServerCentral network, do not export the prefix outside of the current region
23352:5000Anycast

Need help? Send us a note!

Questions or comments regarding our BGP communities can be sent to systems@servercentral.com.

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Chicago, IL 60604

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