Re: Bandwidth issues in the Sprint network
--- braaen@zcorum.com 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. ------------------------------------ I would not use one FTP session to test bandwidth. The rate limiting may be in the FTP software or other area of the computer. Likewise, Speedtest servers (in my opinion) are more marketing tools than testing tools. Try several similarly configured (but separate boxes) FTP servers simultaneously. If you see it go up by a factor of three you've found the issue. I have had to push my four OC-12s to Sprint to the max at times and get full BW. That's in Hawaii, but I imagine it's the same as other areas. scott
See if you can find a nother connector that can help with using iperf. Also, make sure any system testing systems have tuned IP stacks. That info is also linked from the iperf web page. http://dast.nlanr.net/Projects/Iperf/ http://www.psc.edu/networking/projects/tcptune/ Robert D. Scott Robert@ufl.edu Senior Network Engineer 352-273-0113 Phone CNS - Network Services 352-392-2061 CNS Receptionist University of Florida 352-392-9440 FAX Florida Lambda Rail 352-294-3571 FLR NOC Gainesville, FL 32611 -----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of Scott Weeks Sent: Monday, April 07, 2008 5:24 PM To: nanog@merit.edu Subject: Re: Bandwidth issues in the Sprint network --- braaen@zcorum.com 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. ------------------------------------ I would not use one FTP session to test bandwidth. The rate limiting may be in the FTP software or other area of the computer. Likewise, Speedtest servers (in my opinion) are more marketing tools than testing tools. Try several similarly configured (but separate boxes) FTP servers simultaneously. If you see it go up by a factor of three you've found the issue. I have had to push my four OC-12s to Sprint to the max at times and get full BW. That's in Hawaii, but I imagine it's the same as other areas. scott
On the subject of iperf, I just received this today: Iperf 2.0.4 addresses one major and several minor issues with Iperf. The bugs fixed were: * Iperf should no longer consume gratuitous CPU under Linux The help messages * have been expanded to include previously undocumented options The header * the stats report was missing a header which has been replaced. New in Iperf 2.0.4: * Under Linux you can select the TCP congestion algorithm by using the -Z (--linux-congestion) flag * Iperf has a minimal man page! Thanks to Stephen Hemminger and Claus Klein for their patches. This is intended to be the last release in the 2.0 train. Development efforts going forward will concentrate on the 2.1 series of releases. If significant bugs are found there will be a 2.0.5 release, but hopefully we won't need to do that. You can download it at: https://sourceforge.net/project/showfiles.php?group_id=128336 -- R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman@es.net Phone: +1 510 486-8634 Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751
participants (3)
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Kevin Oberman -
Robert D. Scott -
Scott Weeks