Possible explanations for a large hop in latency

Fri Jun 27 00:03:46 UTC 2008

When I asked ATT about the sudden latency jump I see in traceroutes, 
they told me it was due to how their MPLS network is setup.

--John

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
> 
> 