Cogent & Level 3 routing issue?

Jason Canady jason at
Sat Dec 7 20:40:51 UTC 2013

Unfortunately Cogent has a lot of peering issues.  We use them in our 
network blend and we have been having lots of problems with traffic 
outbound to Comcast.  It looks like from South Bend, Indiana on Cogent 
to Chicago / Level 3 we are getting a very tiny amount of packet loss 
and a higher than 'normal' latency of 35ms+.

Where are you connected to Cogent at?  And what destination are you 
going to on Level 3?

Best Regards,


Jason Canady
Unlimited Net, LLC
Responsive, Reliable, Secure
jason at
twitter: @unlimitednet

On 12/7/13 3:14 PM, Matthew Crocker wrote:
> Anyone seeing issues between Cogent & Level3 in NYC?
> I have Sprint & Cogent for bandwidth.   Everything has been humming along for a couple years just fine.   Yesterday around 8:00AM my BGP session with Cogent flapped.  Now, when my Cogent BGP is up I get 100% packet loss in level3 land.  When Cogent BGP is down (i.e. I’m running solely on Sprint)  Everything is fine.
> I have an open ticket with Cogent.  They say they have a ‘capacity issue’ with level3 that has been escalated to executive levels.
> With Sprint & Cogent BGP UP
>   I see traceroutes showing traffic leaving me on Sprint but returning on Cogent (and failing at level3).  I’m guessing it is the level3/cogent border
> With Sprint UP & Cogent Down
>   I see trace routes showing traffic on to/from on Sprint just fine.
> Anyone else having issues?
> -Matt
> --
> Matthew S. Crocker
> President
> Crocker Communications, Inc.
> PO BOX 710
> Greenfield, MA 01302-0710
> E: matthew at
> P: (413) 746-2760
> F: (413) 746-3704
> W:

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