|Used for customer backup when multi-homed to Comcast
|Sets local preference equal to peer routes
|Sets local preference equal to transit routes
|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.
|Prefixes are not sent to anyone. They are contained entirely within AS7922 only
|Prefixes are not sent to ALL peers. Prefixes still sent to customers
|Do not announce prefixes to AS 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.
|Prepend x1 to ALL PEERS
|Prepend x1 to AS XXX
|Prepend x2 to ALL PEERS
|Prepend x2 to AS XXX
|Prepend x3 to ALL PEERS
|Prepend x3 to AS XXX
|Prepend x4 to ALL PEERS
|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.
|Blackhole traffic (only allowed on /32 routes)