----- Forwarded message from Andreas Ott <[email protected]> ----- From: Andreas Ott <[email protected]> Date: Tue, 28 Jun 2011 08:23:46 -0700 To: Eugen Leitl <[email protected]>, [email protected] Cc: NANOG list <[email protected]> Subject: Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) User-Agent: Mutt/1.2.5.1i
Hi, On Tue, Jun 28, 2011 at 10:52:55AM +0200, Eugen Leitl wrote: > ----- Forwarded message from William Salt <[email protected]> ----- > From: William Salt <[email protected]> > Date: Tue, 28 Jun 2011 08:03:25 +0100 > To: [email protected] > Subject: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3) > Reply-To: [email protected] > 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!] ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org";>leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected] Commercial support available - https://portal.pfsense.org
