nanog mailing list archives
Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3)
From: Andreas Ott <andreas () naund org>
Date: Tue, 28 Jun 2011 08:23:46 -0700
Hi, On Tue, Jun 28, 2011 at 10:52:55AM +0200, Eugen Leitl wrote:
----- Forwarded message from William Salt <williamejsalt () googlemail com> ----- From: William Salt <williamejsalt () googlemail com> Date: Tue, 28 Jun 2011 08:03:25 +0100 To: support () pfsense com Subject: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Reply-To: support () pfsense com
Each TCP connection starts very slowly, and will max out at around 190mbps, taking nearly 2 minutes to climb to this speed before *plateauing*. We have to initiate many (5+) connections to saturate the link with tcp connections with iperf. ----- End forwarded message -----
You pretty much solved your own puzzle right there: the throughput on a single TCP connection will max out at the value determined by the bandwidth delay product (excluding other strange conditions, such as deep buffers). Here is a calculator online: http://www.switch.ch/network/tools/tcp_throughput/ -andreas [who has to explain this about once a week to customers who think that they bought a GigE connection but then can't "ftp" a file from coast to coast at 1Gbps throughput. Use multiple TCP streams!]
Current thread:
- [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Eugen Leitl (Jun 28)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Jérôme Nicolle (Jun 28)
- RE: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Leigh Porter (Jun 28)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Mikael Abrahamsson (Jun 28)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) kristopher . doyen (Jun 28)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Dobbins, Roland (Jun 28)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Rhys Rhaven (Jun 28)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Andreas Ott (Jun 28)
- RE: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Leigh Porter (Jun 28)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Cameron Byrne (Jun 28)
- RE: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Leigh Porter (Jun 28)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Cameron Byrne (Jun 28)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) PC (Jun 28)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Cameron Byrne (Jun 28)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Mikael Abrahamsson (Jun 28)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Tony Finch (Jun 29)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Nick Hilliard (Jun 29)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Mikael Abrahamsson (Jun 29)
- RE: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Leigh Porter (Jun 28)
- Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) Jérôme Nicolle (Jun 28)