Cogent BGP Community String

Cogent will send the customer a complete BGP table without aggregating the internal Cogent routes. This is useful for customers who are multi-homed within the Cogent Network.

Local Preference

All customer routes announced to Cogent will have a local pref of 130. The customer can control the local preference for their announcements by using a BGP community string that is passed to Cogent in the BGP session. The following table lists the BGP community strings and the corresponding local preference that will be set when they are used.

BGP Community String	Local Pref	Effect
174:10	10	Set customer route local preference to 10 (below everything-least preferred)
174:70	70	Set customer route local preference to 70 (below peers)
174:120	120	Set customer route local preference to 120 (below customer default )
174:125	125	Set customer route local preference to 125 (below customer default)
174:135	135	Set customer route local preference to 135 (above customer default)
174:140	140	Set customer route local preference to 140 (above customer default)

AS Padding

Customers with public AS numbers may pad their AS path to control the desirability of their
connections. Customers with an assigned private AS number from Cogent may not pad their AS path. Cogent will ignore any padding of private AS numbers from customers.

No-Export

Customers can control the "no-export" settings of their routes with the following community

strings:

BGP Community String	Effect
174:970	Do not send route to NA (North America) - not accepted in NA
174:971	Do not send route to NA peers.
174:975	Set local preference to 10 in NA.
174:980	Do not send route to EU (Europe) - not accepted in EU
174:981	Do not send route to EU peers.
174:985	Set local preference to 10 in EU.
174:990	Do not send route to BGP customers, or peers.
174:991	Do not send route to peers.

Peer Controls

Effective on ALL peer, non-granular.

BGP Community String	Effect
174:3000	Do not announce.
174:3001	Prepend 174 1 time.
174:3002	Prepend 174 2 times.
174:3003	Prepend 174 3 times

Detailed Non-Transit Peer

Cogent will send its internal routes without aggregating them, as well as the routes of other Cogent BGP customers. This is recommended for customers who are multi-homed within the Cogent Network and who want to use their connection to only access the Cogent Network.

Other BGP Communities

Routes announced to customers by Cogent will have one of the following communities associated with them:

BGP Community String	Description
174:21000	Route is learned from NA (North America) non-customer.
174:21001	Route is NA internal or customer route.
174:21100	Route is learned from EU (Europe) non-customer.
174:21101	Route is a EU internal or customer route.

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