[103597] in North American Network Operators' Group
Re: Bandwidth issues in the Sprint network
daemon@ATHENA.MIT.EDU (Sam Stickland)
Tue Apr 8 12:54:41 2008
Date: Tue, 08 Apr 2008 17:51:14 +0100
From: Sam Stickland <sam_mailinglists@spacething.org>
To: Brian Raaen <braaen@zcorum.com>
CC: nanog@merit.edu
In-Reply-To: <200804071506.34371.braaen@zcorum.com>
Errors-To: owner-nanog@merit.edu
Could be your TCP window size? A 17520 byte TCP window (Windows 2000)
will cause a single flow to top out at 5Mbps at about 50ms. What is the
latency on the link?
Try some figures here and see what limit you might be hitting:
http://www.wand.net.nz/~perry/max_download.php?bits_per_second=155000000&ack_size=40&no_delayed_acks=2&mss=1460&rtt=35&wsize=17520&ploss=0
Sam
Brian Raaen wrote:
> I am currently having problems get upload bandwidth on a Sprint circuit. I am
> using a full OC3 circuit. I am doing fine on downloading data, but uploading
> data I can only get about 5Mbps with ftp or a speedtest. I have tested
> against multiple networks and this has stayed the same. Monitoring Cacti
> graphs and the router I do get about 30Mbps total traffic outbound, but
> individual (flows/ip?) test always seem limited. I would like to know if
> anyone else sees anything similar, or where I can get help. The assistance I
> have gotten from Sprint up to this point is that they find no problems. Due
> to the consistency of 5Mbps I am suspecting rate limiting, but wanted to know
> if I was overlooking something else.
>
>
