[105523] in North American Network Operators' Group
Re: Possible explanations for a large hop in latency
daemon@ATHENA.MIT.EDU (Mikael Abrahamsson)
Thu Jun 26 21:16:17 2008
Date: Fri, 27 Jun 2008 03:16:09 +0200 (CEST)
From: Mikael Abrahamsson <swmike@swm.pp.se>
To: nanog list <nanog@merit.edu>
In-Reply-To: <48643DC5.1040208@fluidhosting.com>
Errors-To: nanog-bounces@nanog.org
On Thu, 26 Jun 2008, John T. Yocum wrote:
> The explanation I got, was that the latency seen at the first hop was
> actually a reply from the last hop in the path across their MPLS
> network. Hence, all the following hops had very similar latency.
>
> Personally, I thought it was rather strange for them to do that. And,
> I've never seen that occur on any other network.
This is standard for MPLS, the ICMP TTL expire message is sent along the
LSP and returned via the router at the end of the LSP.
--
Mikael Abrahamsson email: swmike@swm.pp.se
