[96306] in North American Network Operators' Group
Re: from the academic side of the house
daemon@ATHENA.MIT.EDU (JP Velders)
Sun Apr 29 07:59:45 2007
Date: Sun, 29 Apr 2007 14:00:30 +0200 (CEST)
From: JP Velders <jpv@veldersjes.net>
To: Jim Shankland <nanog@shankland.org>
Cc: bmanning@karoshi.com, nanog@merit.edu
In-Reply-To: <E1HgNoL-0006Hd-Hx@mail.shankland.org>
Errors-To: owner-nanog@merit.edu
On Tue, 24 Apr 2007, Jim Shankland wrote:
> Date: Tue, 24 Apr 2007 09:24:13 -0700
> From: Jim Shankland <nanog@shankland.org>
> Subject: Re: from the academic side of the house
> (1) Do the throughput figures count only the data payload (i.e.,
> anything above the TCP layer), or all the bits from the protocol
> stack? If the latter, it seems a little unreasonable to credit
> IPv6 with its own extra overhead -- though I'll concede that with
> jumbo datagrams, that's not all that much.
Data payload is counted as bytes transmitted and received by iperf. So
application layer all the way.
> (2) Getting this kind of throughput seems to depend on a fast
> physical layer, plus some link-layer help (jumbo packets), plus
> careful TCP tuning to deal with the large bandwidth-delay product.
That last part has been researched for quite some time already, though
mainly with "long" transatlantic layer 2 (Ethernet) paths mainly.
> The IP layer sits between the second and third of those three items.
> Is there something about IPv6 vs. IPv4 that specifically improves
> perfomance on this kind of test? If so, what is it?
Not that was specificly mentioned for this test I believe...
Kind regards,
JP Velders
