[outages] Cogent packet loss and jitter

Jeremy Chadwick jdc at koitsu.org
Wed Oct 10 23:21:52 EDT 2012


Otis et al,

I believe Carlos ruled out ICMP prio as a result of doing a native
server-to-server ping, from 208.86.121.129 to 66.62.162.31, as
indicated here:

> --- 66.62.162.31 ping statistics ---
> 62 packets transmitted, 40 received, 35% packet loss, time 61016ms
> rtt min/avg/max/mdev = 53.803/57.115/62.127/1.730 ms

ICMP prio doesn't affect src-to-dst RTT or packet loss; it affects
src-to-administrative-router-IP situations (individual hop probes in
traceroute, sans the destination, etc.).

I think it's more likely that there is a saturated network link
somewhere, given the behaviour shown.  Seeing the return path (not for
latency or packet loss reasons, but to see the peering points) would be
useful though.

-- 
| Jeremy Chadwick                                   jdc at koitsu.org |
| UNIX Systems Administrator                http://jdc.koitsu.org/ |
| Mountain View, CA, US                                            |
| Making life hard for others since 1977.             PGP 4BD6C0CB |

On Wed, Oct 10, 2012 at 09:43:15PM -0500, Otis L. Surratt, Jr. wrote:
> Just a thought have you both ruled out ICMP priortization? Cogent does
> this...
> Also, have you called or just submitted a ticket?
> 
> Everytime, I've opened a ticket....I've gotten a response rather quickly
> and for sure when I call.
> 
> -----Original Message-----
> From: outages-bounces at outages.org [mailto:outages-bounces at outages.org]
> On Behalf Of Brent Jones
> Sent: Wednesday, October 10, 2012 9:10 PM
> To: Carlos Alvarez
> Cc: outages at outages.org
> Subject: Re: [outages] Cogent packet loss and jitter
> 
> I take it back, still seeing high latency, and very poor transfer
> performance  :(
> 
> 38.122.252.185 to 154.54.0.89 (BOS to PDX, Cogent on-net POPs), spiking
> to 150ms latency.
> 
> 
> On Wed, Oct 10, 2012 at 6:30 PM, Carlos Alvarez <carlos at televolve.com>
> wrote:
> > On Wed, Oct 10, 2012 at 6:23 PM, Brent Jones <brent at brentrjones.com>
> wrote:
> >>
> >> (even to other Cogent on-net POPs)
> >
> >
> > This right here is frustrating, since they are in the same city and 
> > same
> > network:
> >
> >  5  vl3810.mag02.phx02.atlas.cogentco.com (66.28.64.209)  12.983 ms  
> > 12.979 ms  12.964 ms
> >  6  * te7-4.ccr01.phx02.atlas.cogentco.com (154.54.85.85)  195.832 ms 
> > *
> >
> > As you might imagine, we have a lot of complaints.
> >
> > --
> > Carlos Alvarez
> > TelEvolve
> > 602-889-3003
> >
> >
> >
> > _______________________________________________
> > Outages mailing list
> > Outages at outages.org
> > https://puck.nether.net/mailman/listinfo/outages
> >
> 
> 
> 
> --
> Brent Jones
> brent at brentrjones.com
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> 
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