nanog mailing list archives

Re: Help interpret a strange traceroute?


From: Larry Sheldon <larrysheldon () cox net>
Date: Mon, 31 Oct 2016 22:53:28 -0500



On 10/31/2016 14:42, William Herrin wrote:
On Mon, Oct 31, 2016 at 3:33 PM, Randy <amps () djlab com> wrote:
Any idea how a traceroute (into my network) could end up this fubar'd?
Discovered this wierd routing while investigating horrendously slow speeds
(albeit no packet loss) to a particular ISP abroad.

Hi Randy,

This is per-packet load balancing. In the forward path the alternates
are different lengths but the traceroute stops as soon as at least one
of the paths reaches the destination.

The return path is also engaged in per-packet load balancing but the
paths are all the same length.

Seems like a lot of bandwidth trying to save bandwidth. Or does that only happen to ICMP?

--
"Everybody is a genius.  But if you judge a fish by
its ability to climb a tree, it will live its whole
life believing that it is stupid."

--Albert Einstein

From Larry's Cox account.


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