AS8220 Communities

Colt implements community marking on it's network to control the announcement of routes and hence flow of traffic into and out of the network. Customers can set some of these communities on prefixes announced to Colt.

Advertisements to Colt Peers

Using the following format 8220:63aee a customer can control how their routes are advertised to peers.

Possible values for a:

0Do not advertise.
1Prepend 8220.
2Prepend 8220 8220.
3Prepend 8220 8220 8220.

Possible values for ee:

01London. 02Frankfurt.
03Paris. 05Milan.
06Madrid. 07Barcelona.
08Amsterdam. 09Brussels.
10Zurich. 11Geneva.
12Vienna. 13Munich.
14Stockholm. 17Copenhagen.
19New York. 21Lisbon.
23Rome. 24Turin.
92All Upstreams. 99All Upstreams and Peers

For example setting 8220:63008 on an advertised route will not announce that route to all peers in Amsterdam and setting 8220:63210 will prepend 8220 8220 on the route to all peers in Zurich.

Special Communities

The following communities allow a customer to blackhole or not advertise a prefix.

8220:63099Do not advertise to any peer.
8220:63999Blackhole all traffic. Can be exact customer prefix or /32 host route.
8220:63800No Export.

The following communities allow a customer to set a local preference on an advertised prefix. It is useful for a customer with multiple connections to Colt or other providers. The default local preference set on all received customer routes is 111.

8220:63700Set local preference to 120.
8220:63600Set local preference to 110.
8220:63900Set local preference to 40.