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