North American Network Operators Group
Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: Bandwidth issues in the Sprint network

  • From: Mike Gonnason
  • Date: Wed Apr 09 10:11:03 2008
  • Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; bh=lGdAkzpjU6eFNDFzjqGrpJl17mjeuz0Uxhg7KKOEea8=; b=AFMzKIANJF4tV5kkEU8q30gVv61YiiYWV/zwZXHCclnh2lCVx87tnBB3+Der3rp12kV8DvDAqDipZDn7FY40ebkA/X8StjxDROrSJYgCnIWPrs94k+apZRv0fCE8LUu03eR0Xm8g+ZwS4ikheUryv0GS2Crb2oRps3gqybr9g6o=
  • Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=BfqnFWSYHO//wnJmA+XvIgCbYwVhbFUlIL4Q9a7MJu6vyeEm6ZuaC9OUVbRSMl4odtvADRV6oWt+aSi5I8z/zQe5AIu/o0+9nmlhxpLTc5JoSNQLZDaRaa71WeTZ/Cdk47wwhs8RxIXD7DrhUodgMOuTbAnFG1uOUSO9v9IuWBI=
On Tue, Apr 8, 2008 at 9:19 AM, Brian Raaen <[email protected]> wrote:
> I have been using the Java based versions of the speed test.  At this point I
>  have had some Sprint people get in contact with me so I will see what they
>  find.  Thank you for all your help to everyone.
>
>
>
>
>  --
>  Brian Raaen
>  Network Engineer
>  [email protected]
>
>
>
> > On Monday 07 April 2008, you 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.
>  >
>  > --
>  > Brian Raaen
>  > Network Engineer
>  > [email protected]
>  >
>

Most of the speed test sites on the Internet basically issue a HTTP
GET request to a server and time the download. For upload they utilize
a HTTP POST via a CGI script and time that. The main issue I have with
these speed tests is that they only use a single TCP session for data
transfer, which is fine if you have a large or self adjusting TCP
window size and a relatively low latency link.

However for high capacity links, it is unlikely (but possible) that
you are planning to use a single TCP session and consume all the
available capacity. Realistically you will have a few dozen
server/applications/users and produce hundreds/thousands of TCP
sessions which will fully utilize the link.

For our PtP customers that have concerns regarding capacity, I
generally they suggest setup iperf at both ends and run a few tests
with multiple TCP sessions so they can independently verify. Hopefully
Sprint will take your concerns to heart and assist you with testing.

-Mike Gonnason