[105511] in North American Network Operators' Group
Re: Possible explanations for a large hop in latency
daemon@ATHENA.MIT.EDU (James R. Cutler)
Thu Jun 26 19:59:57 2008
From: "James R. Cutler" <james.cutler@consultant.com>
To: nanog list <nanog@merit.edu>
In-Reply-To: <!&!AAAAAAAAAAAuAAAAAAAAAKTyXRN5/+lGvU59a+P7CFMBAN6gY+ZG84BMpVQcAbDh1IQAAAATbSgAABAAAAAIgYgvPVlNSJZFmGlF6V4QAQAAAAA=@iname.com>
Date: Thu, 26 Jun 2008 19:58:53 -0400
Errors-To: nanog-bounces@nanog.org
Deep Packet Inspection engine delay. <G>
On Jun 26, 2008, at 6:51 PM, Frank Bulk wrote:
> Our upstream provider has a connection to AT&T (12.88.71.13) where I
> relatively consistently measure with a RTT of 15 msec, but the next
> hop
> (12.122.112.22) comes in with a RTT of 85 msec. Unless AT&T is
> sending that
> traffic over a cable modem or to Europe and back, I can't see a
> reason why
> there is a consistent ~70 msec jump in RTT. Hops farther along the
> route
> are just a few msec more each hop, so it doesn't appear that
> 12.122.112.22
> has some kind of ICMP rate-limiting.
>
> Is this a real performance issue, or is there some logical
> explanation?
>
> Frank
>
>
James R. Cutler
james.cutler@consultant.com
