|7922:290||290||Used for customer backup when multi-homed to Comcast|
|7922:250||250||Sets local preference equal to peer routes|
|7922:150||150||Sets local preference equal to transit routes|
|7922:100||100||Lowest possible value. Used for backup when multi-homed to multiple providers|
The use of these communities allow a customer to prevent their prefixes from being advertised to specific peers. Only those ASes that have a peering relationship with Comcast are available for suppression. An AS that is a customer of Comcast is not enabled for route suppression. Given that this list changes on a regular basis the best way to verify what ASes are available for route suppression, a customer should look at the full Internet feed received from Comcast and look for routes tagged with 7922:3000. Any AS directly connected to AS7922 and is tagged with 7922:3000 is a candidate for route suppression.
|7922:999||Prefixes are not sent to anyone. They are contained entirely within AS7922 only|
|7922:888||Prefixes are not sent to ALL peers. Prefixes still sent to customers|
|65100:XXX||Do not announce prefixes to AS XXX|
|65200:XXX||Announce to AS XXX if 7922:888 is also set|
The use of these communities allow a customer to AS Path Pad advertisements to all or a subset of Comcast Peers. As with route suppression, Only those ASes that have a peering relationship with Comcast are available for prepending.
|65101:0||Prepend x1 to ALL PEERS|
|65101:XXX||Prepend x1 to AS XXX|
|65102:0||Prepend x2 to ALL PEERS|
|65102:XXX||Prepend x2 to AS XXX|
|65103:0||Prepend x3 to ALL PEERS|
|65103:XXX||Prepend x3 to AS XXX|
|65104:0||Prepend x4 to ALL PEERS|
|65104:XXX||Prepend x4 to AS XXX|
The use of this community should only be done in an extreme circumstances. This allows a customer to force traffic destined to any prefixes tagged with 7922:666 to be blackholed ingress to the Comcast Backbone. In order to protect our infrastructure and the Internet from misuse of this, Comcast will only allow a customer to blackhole traffic to a specific /32 that is already permitted by the customers existing ingress prefix filter. This is typically used when a customer is under a DDOS attack, causing congestion on their links from Comcast.
|7922:666||Blackhole traffic (only allowed on /32 routes)|