From: Juliusz Chroboczek <jch@pps.univ-paris-diderot.fr>
To: Baptiste Jonglez <baptiste.jonglez@ens-lyon.fr>
Cc: babel-users@lists.alioth.debian.org, bloat@lists.bufferbloat.net
Subject: Re: [Bloat] [Babel-users] RTT stability inside a GRE tunnel
Date: Tue, 02 Jul 2013 02:02:25 +0200 [thread overview]
Message-ID: <871u7hesmm.wl%jch@pps.univ-paris-diderot.fr> (raw)
In-Reply-To: <20130701164607.GB12090@ens-lyon.fr>
> While experimenting with the RTT-aware branch of babeld, I ran into an
> odd but interesting behaviour: between two given hosts reachable over
> the Internet, the RTT is more stable inside a GRE tunnel than outside.
The RTT is around 300 ms for both kinds of packets. GRE packets have
virtually no jitter, while ICMP packets have some 15ms jitter, which
would appear to be completely random.
My guess would be that there might be a router in the way that handles
GRE packets in hardware, and ICMP packets in software. The extra 15
ms is the CPU time spent on processing the ICMP packets. Still, the
nondeterminacy is weird.
Anybody seen anything similar?
-- Juliusz
next prev parent reply other threads:[~2013-07-02 0:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20130701164607.GB12090@ens-lyon.fr>
2013-07-01 23:58 ` [Bloat] Fwd: " Juliusz Chroboczek
2013-07-02 0:02 ` Juliusz Chroboczek [this message]
2013-07-02 4:48 ` [Bloat] " Mikael Abrahamsson
2013-07-02 11:08 ` Baptiste Jonglez
2013-07-02 11:27 ` Mikael Abrahamsson
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