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Thursday, November 27, 2014
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This document has been extracted from User Guide V5.pdf.


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 community string that is passed to Cogent in the BGP session. The following table lists the community strings and the corresponding local preference that will be set when they are used.

Community StringLocal PrefEffect
174:1010Set customer route local preference to 10 (below everything-least preferred)
174:7070Set customer route local preference to 70 (below peers)
174:120120Set customer route local preference to 120 (below customer default)
174:125125Set customer route local preference to 125 (below customer default)
174:135135Set customer route local preference to 135 (above customer default)
174:140140Set 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.


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

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

Peer Controls

Effective on ALL peer, non-granular.

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

Other Communities

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

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