Cogent input

Andrew Mulholland andy-nanog at
Thu Jun 11 14:01:59 UTC 2009

At $JOB-1 we used Cogent.

Lots of horror stories had been heard about them.

We didn't have such problems.

Had nx1Gig from them.

On the few occasions where we had some slight issues, I was happy to
be able to get through to some one useful on the phone quickly, and
not play pass the parcel with call centre operatives.

and at least in the quantities we were buying they were significantly
better value than others, which was the primary reason we went with


On Thu, Jun 11, 2009 at 2:55 PM, Paul Stewart<pstewart at> wrote:
> Our experience with them was at least one major (longer than an hour)
> outages PER MONTH and many of those times they were black holing our
> routes in their network which was the most damaging aspect.  The outages
> were one thing but when our routes still somehow managed to get
> advertised in their network (even though our BGP session was down) that
> really created issues.  I have heard from some nearby folks who still
> have service that it's gotten better, but we are also in the "regional
> offering" when it comes to IP Transit and have sold connections to many
> former Cogent customers who were fed up and left.
> I have found with Cogent that you will get a LOT of varying opinions on
> them - there are several other players (at least in our market) that are
> priced very similar now and have a better history behind them.....
> The specific de-peering issues never effected us much due to enough
> diversity in our upstreams and a fair amount of direct/public peering...
> Thanks,
> Paul
> -----Original Message-----
> From: Justin Shore [mailto:justin at]
> Sent: Thursday, June 11, 2009 9:47 AM
> Subject: Cogent input
> I'm in search of some information about Cogent, it's past, present and
> future.  I've heard bits and pieces about Cogent's past over the years
> but by no means have I actively been keeping up.
> I'm aware of some (regular?) depeering issues.  The NANOG archives have
> given me some additional insight into that (recurring?) problem.  The
> reasoning behind the depeering events is a bit fuzzy though.  I would be
> interested in people's opinion on whether or not they should be consider
> for upstream service based on this particular issue.  Are there any
> reasonable mitigation measures available to Cogent downstreams if
> (when?) Cogent were to be depeered again?  My understanding is that at
> least on previous depeering occasion, the depeering partner simply
> null-routed all prefixes being received via Cogent, creating a blackhole
> essentially.  I also recall reading that this meant that prefixes being
> advertised and received by the depeering partner from other peers would
> still end up in the blackhole.  The only solution I would see to this
> problem would be to shut down the BGP session with Cogent and rely on a
> 2nd upstream.  Are there any other possible steps for mitigation in a
> depeering event?
> I also know that their bandwidth is extremely cheap.  This of course
> creates an issue for technical folks when trying to justify other
> upstream options that cost significantly more but also don't have a
> damaging history of getting depeered.
> Does Cogent still have an issue with depeering?  Are there any
> reasonable mitigation measures or should a downstream customer do any
> thing in particular to ready themselves for a depeering event?  Does
> their low cost outweigh the risks?  What are the specific risks?
> Thanks
>  Justin
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