Re: Bandwidth issues in the Sprint network
Some people wanted to know what I found the problem to be. I have discovered. the problem for a fact is the TCP window size on uploads. I have a Linux box that I changed the Window sizes to match and I still get 32k on a upload window and 64k on a download window. With a ping time of 50ms I have a max theoretical throughput of 5.2Mbps Which is about what I was getting. The formula to calculate this is the following. (((Ts/Tw)*Rtd)/1000)+((Ts*8)/(Lr*1000))) Where the following are Ts = Transfer size in Bytes Tw = Tcp Window size in Bytes Rtd = Round trip Delay in milliseconds Lr = Line rate in bps At this point I am still trying to locate the offending device that is changing the window size. After I determine for sure whether the problem is with my router, the sprint network, or another upstream system I will let everybody know what I find. -- Brian Raaen Network Engineer [EMAIL PROTECTED] On Monday 07 April 2008, 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. -- Brian Raaen Network Engineer [EMAIL PROTECTED] signature.asc Description: This is a digitally signed message part.
Re: Bandwidth issues in the Sprint network
On Thu, Apr 17, 2008 at 1:00 PM, Brian Raaen [EMAIL PROTECTED] wrote: Some people wanted to know what I found the problem to be. I have discovered. the problem for a fact is the TCP window size on uploads. I have a Linux box that I changed the Window sizes to match and I still get 32k on a upload window and 64k on a download window. With a ping time of 50ms I have a max theoretical throughput of 5.2Mbps Which is about what I was getting. The formula to calculate this is the following. (((Ts/Tw)*Rtd)/1000)+((Ts*8)/(Lr*1000))) Where the following are Ts = Transfer size in Bytes Tw = Tcp Window size in Bytes Rtd = Round trip Delay in milliseconds Lr = Line rate in bps At this point I am still trying to locate the offending device that is changing the window size. After I determine for sure whether the problem is with my router, the sprint network, or another upstream system I will let everybody know what I find. -- Brian Raaen Network Engineer [EMAIL PROTECTED] On Monday 07 April 2008, 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. -- Brian Raaen Network Engineer [EMAIL PROTECTED] Thanks for reporting back to curious minds. Mike Gonnason
RE: Bandwidth issues in the Sprint network
even with tuned TCP window sizes, make sure you don't have TCP syncookies enabled on either endpoint. many syncookie implementations have implications on supporting RFC1323 options. cheers, lincoln. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Brian Raaen Sent: Friday, 18 April 2008 7:00 AM To: nanog@merit.edu Subject: Re: Bandwidth issues in the Sprint network Some people wanted to know what I found the problem to be. I have discovered. the problem for a fact is the TCP window size on uploads. I have a Linux box that I changed the Window sizes to match and I still get 32k on a upload window and 64k on a download window. With a ping time of 50ms I have a max theoretical throughput of 5.2Mbps Which is about what I was getting. The formula to calculate this is the following. (((Ts/Tw)*Rtd)/1000)+((Ts*8)/(Lr*1000))) Where the following are Ts = Transfer size in Bytes Tw = Tcp Window size in Bytes Rtd = Round trip Delay in milliseconds Lr = Line rate in bps At this point I am still trying to locate the offending device that is changing the window size. After I determine for sure whether the problem is with my router, the sprint network, or another upstream system I will let everybody know what I find. -- Brian Raaen Network Engineer [EMAIL PROTECTED] On Monday 07 April 2008, 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.
Re: Bandwidth issues in the Sprint network
Once upon a time, Lincoln Dale [EMAIL PROTECTED] said: even with tuned TCP window sizes, make sure you don't have TCP syncookies enabled on either endpoint. IIRC Linux (at least) syncookies only come into play when you are being syn-flooded (i.e. when the kernel has to start dropping syns). Having them enabled at other times has no impact, so there's rarely (if ever) a reason to disable them. -- Chris Adams [EMAIL PROTECTED] Systems and Network Administrator - HiWAAY Internet Services I don't speak for anybody but myself - that's enough trouble.
RE: Bandwidth issues in the Sprint network
I tried this on three laptops (two different models), and none of them would fully boot. They would lock up at different points. Unless someone has some workarounds, I think I'll be trying another ISO package. Regards, Frank -Original Message- From: Tim Peiffer [mailto:[EMAIL PROTECTED] Sent: Wednesday, April 09, 2008 9:50 AM To: [EMAIL PROTECTED] Cc: nanog@merit.edu Subject: Re: Bandwidth issues in the Sprint network http://e2epi.internet2.edu/network-performance-toolkit/network-performance-t oolkit.iso Frank Bulk wrote: Does anyone know of bootable Linux CD with iperf on it? Frank -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mike Gonnason Sent: Wednesday, April 09, 2008 9:05 AM To: nanog@merit.edu Subject: Re: Bandwidth issues in the Sprint network 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
RE: Bandwidth issues in the Sprint network
Good idea, but the other side doesn't have a Cisco box. Frank -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Wednesday, April 09, 2008 11:02 AM To: Michael Holstein Cc: [EMAIL PROTECTED]; nanog@merit.edu Subject: Re: Bandwidth issues in the Sprint network You can also use ttcp from the command line, useful if its cisco on both ends of the circuit. sr01#ttcp transmit or receive [receive]: transmit Target IP address: 1.1.1.1 calculate checksum during buffer write [y]: perform tcp half close [n]: send buflen [32768]: send nbuf [2048]: bufalign [16384]: bufoffset [0]: port [5001]: sinkmode [y]: buffering on writes [y]: show tcp information at end [n]: ttcp-t: buflen=32768, nbuf=2048, align=16384/0, port=5001 tcp - 1.1.1.1 sr02#ttcp transmit or receive [receive]: receive packets asynchronously [n]: perform tcp half close [n]: receive buflen [32768]: bufalign [16384]: bufoffset [0]: port [5001]: sinkmode [y]: rcvwndsize [32768]: ack frequency [0]: delayed ACK [y]: show tcp information at end [n]: ttcp-r: buflen=32768, align=16384/0, port=5001 rcvwndsize=32768, delayedack=yes tcp Michael Holstein [EMAIL PROTECTED] wrote: Does anyone know of bootable Linux CD with iperf on it? Knoppix STD (security tools distro) http://www.knoppix-std.org/tools.html Cheers, Michael Holstein Cleveland State University
Re: Bandwidth issues in the Sprint network
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
RE: Bandwidth issues in the Sprint network
Does anyone know of bootable Linux CD with iperf on it? Frank -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mike Gonnason Sent: Wednesday, April 09, 2008 9:05 AM To: nanog@merit.edu Subject: Re: Bandwidth issues in the Sprint network 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
Re: Bandwidth issues in the Sprint network
A quick search comes up with Scientific Linux, but I cannot provide any claims to suitability. I have never even heard of it before, but it is provided as a LiveCD. http://linux.web.psi.ch/livecd/software.html -Mike Gonnason On Wed, Apr 9, 2008 at 6:28 AM, Frank Bulk [EMAIL PROTECTED] wrote: Does anyone know of bootable Linux CD with iperf on it? Frank -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mike Gonnason Sent: Wednesday, April 09, 2008 9:05 AM To: nanog@merit.edu Subject: Re: Bandwidth issues in the Sprint network 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
Re: Bandwidth issues in the Sprint network
Does anyone know of bootable Linux CD with iperf on it? Knoppix STD (security tools distro) http://www.knoppix-std.org/tools.html Cheers, Michael Holstein Cleveland State University
RE: Bandwidth issues in the Sprint network
Not 100% sure about iperf but I2 has a nice Network Performance Toolkit that runs on top of Knoppix and they have a downloadable ISO image... Get the ISO here... http://e2epi.internet2.edu/network-performance-toolkit.html Interesting doc on configuring toolkit from SLAC... http://confluence.slac.stanford.edu/display/IEPM/Network+Performance+Too lkit Bill Murphy Senior Network Analyst University of Texas Health Science Center - Houston -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Michael Holstein Sent: Wednesday, April 09, 2008 10:00 AM To: [EMAIL PROTECTED] Cc: nanog@merit.edu Subject: Re: Bandwidth issues in the Sprint network Does anyone know of bootable Linux CD with iperf on it? Knoppix STD (security tools distro) http://www.knoppix-std.org/tools.html Cheers, Michael Holstein Cleveland State University
Re: Bandwidth issues in the Sprint network
You can also use ttcp from the command line, useful if its cisco on both ends of the circuit. sr01#ttcp transmit or receive [receive]: transmit Target IP address: 1.1.1.1 calculate checksum during buffer write [y]: perform tcp half close [n]: send buflen [32768]: send nbuf [2048]: bufalign [16384]: bufoffset [0]: port [5001]: sinkmode [y]: buffering on writes [y]: show tcp information at end [n]: ttcp-t: buflen=32768, nbuf=2048, align=16384/0, port=5001 tcp - 1.1.1.1 sr02#ttcp transmit or receive [receive]: receive packets asynchronously [n]: perform tcp half close [n]: receive buflen [32768]: bufalign [16384]: bufoffset [0]: port [5001]: sinkmode [y]: rcvwndsize [32768]: ack frequency [0]: delayed ACK [y]: show tcp information at end [n]: ttcp-r: buflen=32768, align=16384/0, port=5001 rcvwndsize=32768, delayedack=yes tcp Michael Holstein [EMAIL PROTECTED] wrote: Does anyone know of bootable Linux CD with iperf on it? Knoppix STD (security tools distro) http://www.knoppix-std.org/tools.html Cheers, Michael Holstein Cleveland State University
Re: Bandwidth issues in the Sprint network
Has this circuit ever run clean(normal)? -M On Mon, Apr 7, 2008 at 1:06 PM, Brian Raaen [EMAIL PROTECTED] 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]
Re: Bandwidth issues in the Sprint network
Currently there is not a proxy server in the network, although when using some of the test on dslreports.com there is a message about compression being used for the upload and to remove proxy settings. I have also been testing using FTP on a *nix server as well. Both the server and PC are connect to a Cisco 2960 switch in the headend that is connected to the 7200 router. I can transfer ftp at about 80Mbps between the PC and the server, so they are not IO bound. The Site I am testing with is a ftp server located in a colo facility that we use and has sufficient bandwidth. This circuit is clean in the sense of not having CRC, framing or other errors but this is a new circuit and we have never gotten more than 5Mbps out of a single session (flow/ip) across the wan. I would have to double check the mtu, but it is currently the default. -- Brian Raaen Network Engineer [EMAIL PROTECTED] On Monday 07 April 2008, 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. -- Brian Raaen Network Engineer [EMAIL PROTECTED] signature.asc Description: This is a digitally signed message part.
RE: Bandwidth issues in the Sprint network
Try using the Java test on DSLReports rather than the Flash based test. I've found it to be much more accurate. I also receive the message about compression being used when I test with the flash test. I think it may be a bug. Matthew Evans, MCSA Alpha Theory | “the right decision, every time.” 2201 Coronation Blvd., Suite 140 Charlotte, NC 28227 (704) 307-2914 x205 www.alphatheory.com ALPHA THEORY QUICK DEMO (click here) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Brian Raaen Sent: Tuesday, April 08, 2008 9:49 AM To: nanog@merit.edu Subject: Re: Bandwidth issues in the Sprint network Currently there is not a proxy server in the network, although when using some of the test on dslreports.com there is a message about compression being used for the upload and to remove proxy settings. I have also been testing using FTP on a *nix server as well. Both the server and PC are connect to a Cisco 2960 switch in the headend that is connected to the 7200 router. I can transfer ftp at about 80Mbps between the PC and the server, so they are not IO bound. The Site I am testing with is a ftp server located in a colo facility that we use and has sufficient bandwidth. This circuit is clean in the sense of not having CRC, framing or other errors but this is a new circuit and we have never gotten more than 5Mbps out of a single session (flow/ip) across the wan. I would have to double check the mtu, but it is currently the default. -- Brian Raaen Network Engineer [EMAIL PROTECTED] On Monday 07 April 2008, 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. -- Brian Raaen Network Engineer [EMAIL PROTECTED]
Re: Bandwidth issues in the Sprint network
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=15500ack_size=40no_delayed_acks=2mss=1460rtt=35wsize=17520ploss=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.
Re: Bandwidth issues in the Sprint network
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] signature.asc Description: This is a digitally signed message part.
Re: Bandwidth issues in the Sprint network
On Mon, 07 Apr 2008 15:06:21 EDT, Brian Raaen said: 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. TCP window size tuning? I'd look there first... pgp5sXCAaiPAS.pgp Description: PGP signature
Re: Bandwidth issues in the Sprint network
--- [EMAIL PROTECTED] 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
RE: Bandwidth issues in the Sprint network
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 [EMAIL PROTECTED] 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: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] 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 --- [EMAIL PROTECTED] 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
Re: Bandwidth issues in the Sprint network
--- [EMAIL PROTECTED] wrote: --- I would like to second the recommendation and go one further. Internet2 has released a performance toolkit that is run from CD. I would like to -- Robert D. Scott wrote: See if you can find a nother connector that can help with using iperf. Also, --- The thing to note about most tools like these is you need a box on both sides of the circuit using the same software. One could be 'out there' on the internet, but the further 'out there' your other box is, the less valid your test is. scott
