congestion between Cogent and CenturyLink

Thu Feb 27 16:58:58 UTC 2014

Hello,

We send periodic 10-15Mbps bursts of traffic to a business partner and it
appears to transition from Cogent to Century Link in Atlanta. During the
day performance is normal and latency appears acceptable on a trace route.

12 ms 13 ms 12 ms te0-6-1-7.rcr21.msp01.atlas.cogentco.com [38.88.188.41]

26 ms 26 ms 27 ms be2410.ccr22.ord01.atlas.cogentco.com [154.54.7.229]

43 ms 44 ms 44 ms be2099.ccr22.atl01.atlas.cogentco.com [154.54.28.74]

44 ms 44 ms 44 ms be2051.ccr21.atl02.atlas.cogentco.com [154.54.0.162]

43 ms 42 ms 43 ms qwest.atl02.atlas.cogentco.com [154.54.13.30]

49 ms 49 ms 50 ms min-edge-10.inet.qwest.net [205.171.128.154]

But after hours latency spikes and throughput drops to less than 1Mbps.

te8-3.ccr01.msp01.atlas.cogentco.com (38.88.188.41) 4.603 ms

te0-0-0-19.mpd22.ord01.atlas.cogentco.com (154.54.1.230) 17.838 ms

be2099.ccr22.atl01.atlas.cogentco.com (154.54.28.74) 33.156 ms

be2051.ccr21.atl02.atlas.cogentco.com (154.54.0.162) 36.449 ms

qwest.atl02.atlas.cogentco.com (154.54.13.30) 89.583 ms

min-edge-10.inet.qwest.net (205.171.128.150) 89.806 ms

Century Link stated that Cogent is oversubscribing the link, and that
they've requested Cogent resolve the problem, but that action has yet to be
taken.  I've tried reaching out to Cogent but as we're not a direct
customer they wouldn't provide assistance.

Has anyone else seen similar issues?

Thanks,

Aidan