Slow FTP

[bsmither]

Hi,

I'm having a few problems with an FTP server that I have set up at my work place.  Ports at both ends are set up correctly and FTP connections can be made - the only problem is that they're marginally slower than I would like!

Work Connection:

• Fibre optic link to exchange
• 8mBit up / 8mBit down (yes, it's symmetrical)
• Provided by a small ISP called Bridge Partners
• Contended 10:1
• FTP Server - Filezilla Server
• Firewall - Watchguard (inc VPN endpoint)

Home Connection:

• 8128 kBps up / 832 kBps down
• Home SuperPro connection from IDNET
• Zyxel P-661HW-D1 Router
• Wired network connection

For my home connection I have deliberately gone for the SuperPro option to get the better upload and improved priority on BT's network.  The main place that I connect to is my work for grabbing test data etc.  When transferring data to work I can max out my upload at just under 1mBit/s but when downloading from work I can only achieve 2mBit/s instead of the 8mBit/s I should get.

I have tried to diagnose this problem by connecting to different ftp servers from home, and, connecting to work from different places.  The results are very confusing!

When connecting to work from other places I can achieve the full 8mBit/s both up and down.  So it's not the work end....

When connecting to ftp.freebsd.org from home I can download an ISO image at 8mBit/s.   So it's not the home connection either!

This isn't just bad luck either - I've tried connecting from home to work at all times of day / days of the week and can never achieve over 2mBit/s.  I've done traceroutes of the link both ways and all appears ok - all hops check out.

Any ideas where I should go next with this or should I just give up and accept what I have?

Thanks for any ideas / suggestions,

Ben

[Lance]

Have you tried checking or changing you MTU value? I'm wondering if packets are getting fragmented along the way.

[bsmither]

Thanks for the suggestion.

I've just tried lowering the MTU of my router down to around 600 (and several steps in between) but there is no visible improvement in bandwidth.

A few things that I forgot to mention

• Throughput using a VPN link direct to work is still 2mBit (ftp or windows file transfer over VPN)
• I've also tried a VPN link to a fast machine in Cambridge to act as a stepping stone and maybe stop any routing issues but still only achieve 2mBit
• Transfers between the Cambridge network and my work run at 8mBit

[Bill]

Thanks for the suggestion.

I've just tried lowering the MTU of my router down to around 600 (and several steps in between) but there is no visible improvement in bandwidth.

Put your router's MTU back to 1500 and set the computer's MTU to about 1460. Work down from there on the computer only, I think the minimum legal value is 1280 but don't quote me on that!

The computer should never be using a higher value than the router.

[bsmither]

ok, all back.  Had read similar things about MTU's on a google search.

More info:

Traceroute: Home to Work
traceroute to 193.34.xxx.xxx (193.34.xxx.xxx), 30 hops max, 38 byte packets
1  192.168.15.1 (192.168.15.1)  0.547 ms  0.516 ms  0.495 ms
2  telehouse-gw2-lo1.idnet.net (212.69.63.51)  32.379 ms  29.969 ms  29.062 ms
3  telehouse-gw5-e4-400.idnet.net (212.69.63.245)  29.832 ms  30.770 ms  29.585 ms
4  telehouse-gw3-g0-1-400.idnet.net (212.69.63.243)  30.525 ms  29.890 ms  29.455 ms
5  linx-gw.ltn1.intl.telstra.net (195.66.224.14)  31.257 ms  28.755 ms  30.269 ms
6  146.101.1.226 (146.101.1.226)  31.769 ms  31.228 ms  32.512 ms
7  146.101.144.4 (146.101.144.4)  33.765 ms  31.984 ms  32.039 ms
8  xxxx.co.uk (193.34.xxx.xxx)  61.559 ms  58.705 ms  58.409 ms

Traceroute: Work to Home
traceroute to 93.89.xxx.xxx (93.89.xxx.xxx), 30 hops max, 38 byte packets
1  10.0.38.254 (10.0.38.254)  0.292 ms  0.168 ms  0.127 ms
2  xxx.xxx.34.193.bridgep.com (193.34.xxx.xxx)  25.916 ms  25.810 ms  21.688 ms
3  146.101.144.1 (146.101.144.1)  26.023 ms  22.193 ms  26.529 ms
4  146.101.1.225 (146.101.1.225)  27.574 ms  27.623 ms  27.739 ms
5  telehouse-gw.idnet.net (195.66.224.181)  29.109 ms  28.315 ms  28.352 ms
6  telehouse-gw2-g0-2-400.idnet.net (212.69.63.242)  28.024 ms  28.131 ms  28.588 ms
7  custxxx-dsl93-89-xxx.idnet.net (93.89.xxx.xxx)  60.261 ms  60.445 ms  60.649 ms

[Steve]

Not sure I can add anymore but

What's the computer resource usage like on the 2mb download? Anything in the client software logs?

[bsmither]

CPU usage is 4%, memory usage 25%.

Just checked Speedtest.net and I get 6.59 mBit down and 0.42 mBit up (a little lower than usual).  Immediately before this FTP was struggling to get to 2mBit, dipping to 0.5mBit.

[Rik]

Hi Ben and welcome to the forum.

Like Steve, I can't think of anything much to add. You've proved your connection is OK to other sites, you've proved the work setup is OK from other locations. Do you have a trace from one of those. ATM, I'm wondering if there's a routing problem at hop 5.

[Ray]

  Ben.

[Glenn]

What speeds do other users get from the FTP server, it maybe limited to 2mb per connection?

[Rik]

Good thinking, Glenn, it's possible the sysadmin is limiting bandwidth.

[Steve]

Except he gets full download from other locations to the same server. Are the correct ports been forwarded in PASV mode in the router

[Rik]

I saw that, Steve, but as nothing makes sense so far, Glenn's idea seemed feasible.

[bsmither]

Hi Glenn / Rik,

I am (one of) the sys admins for the work end of the link and was responsible for commissioning the FTP server.  I have fully checked the config of the FTP server and our firewall and there is no limiting in place.  This is backed up by the ability to achieve the full 8mBit up / 8mBit down from a computer in Cambridge.  The slow connection only occurs when I try to connect to work from IDNet (not saying that it's necessarily IDNet's fault though!).

Rik:

Below are some traceroute results to work from Cambridge and to home (IDNet) from Cambridge.  Looks like hop 5 onwards are the same as my link from home to work.  Given that I can achieve the full 8mBit from Cambridge I guess this implies that this part of the route is ok.  On the link from home to work everything before hop 5 is on IDNet.  Is it worth raising a ticket / issue with IDNet or do you think that the 2mBit I get is too high for them to be concerned with?

Thanks again for all your help

Ben

Traceroute: Cambridge to Work
traceroute to 193.34.xxx.xxx (193.34.xxx.xxx), 64 hops max, 52 byte packets
1  192.168.250.1 (192.168.250.1)  1.142 ms  0.779 ms  0.469 ms
2  gw-427.net.cam.ac.uk (131.111.51.62)  1.486 ms  1.719 ms  1.472 ms
3  route-cent-bkbone.net.cam.ac.uk (131.111.2.126)  2.243 ms  2.129 ms  1.495 ms
4  route-cent.route-enet.net.cam.ac.uk (192.153.213.193)  1.748 ms  1.631 ms  1.489 ms
5  xe-11-3-0.camb-rbr1.eastern.ja.net (146.97.130.1)  1.487 ms  1.652 ms  1.490 ms
6  xe-2-0-0.lond-rbr1.eastern.ja.net (146.97.65.33)  3.238 ms  3.409 ms  3.239 ms
7  ae3.lond-sbr4.ja.net (146.97.35.125)  6.991 ms  3.417 ms  3.235 ms
8  ae0.lond-gw-ixp4.ja.net (146.97.35.182)  3.235 ms  3.150 ms  3.238 ms
9  linx-gw.ltn1.intl.telstra.net (195.66.224.14)  3.488 ms  3.379 ms  3.484 ms
10  146.101.1.226 (146.101.1.226)  5.234 ms  5.172 ms  5.232 ms
11  146.101.144.4 (146.101.144.4)  6.746 ms  7.169 ms  6.486 ms
12  xxxxx.co.uk (193.34.xxx.xxx)  25.982 ms  29.409 ms  31.971 ms

Traceroute: Cambridge to Home
traceroute to 93.89.xxx.xxx (93.89.xxx.xxx), 64 hops max, 52 byte packets
1  192.168.250.1 (192.168.250.1)  1.021 ms  0.607 ms  0.479 ms
2  gw-427.net.cam.ac.uk (131.111.51.62)  1.495 ms  1.441 ms  1.768 ms
3  route-cent-bkbone.net.cam.ac.uk (131.111.2.126)  1.776 ms  1.554 ms  2.201 ms
4  route-cent.route-enet.net.cam.ac.uk (192.153.213.193)  1.716 ms  1.794 ms  1.739 ms
5  xe-11-3-0.camb-rbr1.eastern.ja.net (146.97.130.1)  1.487 ms  1.535 ms  1.492 ms
6  xe-2-0-0.lond-rbr1.eastern.ja.net (146.97.65.33)  3.241 ms  3.253 ms  3.240 ms
7  ae3.lond-sbr4.ja.net (146.97.35.125)  3.233 ms  3.452 ms  3.233 ms
8  ae0.lond-gw-ixp4.ja.net (146.97.35.182)  3.238 ms  3.252 ms  3.244 ms
9  telehouse-gw.idnet.net (195.66.224.181)  3.742 ms  3.388 ms  3.484 ms
10  telehouse-gw2-g0-2-400.idnet.net (212.69.63.242)  19.986 ms  8.122 ms  3.487 ms
11  custxxx-dsl93-89-xxx.idnet.net (93.89.1xxx.xxx)  32.972 ms  32.891 ms  32.223 ms

[Steve]

I agree doesn't make sense at all. Is the same FTP client been used at the locations with better downloads. Lastly I believe that particular has the ability to restrict bandwidth for users and traffic type however that's probably contradicted by the better download from the other FTP site mentioned.

[Rik]

Is it worth raising a ticket / issue with IDNet or do you think that the 2mBit I get is too high for them to be concerned with?

I already asked them, Ben. If you're getting full speed from other FTP sites and general web use, then your connection is OK. The routing shouldn't be an issue (and there was me thinking I'd spotted something ) as the packets will take the fastest open path available to them at the time. Like Steve, the only thing I can think of at this point is that the FTP clients are different, or set up differently. When you've tested from other locations, has it been on the same machine?

[Technical Ben]

Do you have a virus scanner? They can have a tendency to scan each file, and really swamp a download at least (worth it, but it takes about 10 seconds longer with them on per file). No idea if it does the same with uploads.
The only other thing I would guess is different, is OS. Is work still on XP? Are you using windows 7?
http://www.windowsreference.com/windows-7/slow-network-file-copy-issues-in-windows-7-caused-by-remote-differential-compression/

That's the only thing I can think of. I'm not very... er, "technical".   

[bsmither]

Hi Rik,

The testing from other Cambridge has been from a different machine.  I have, however, tried from two different machines at home (one linux, one XP).

From the linux and XP machines both Passive and Active modes work.  I went to some length to get these both set up - one requires local port forwarding and the other requires ports to be forwarded at the server end. 

I think my next step will be to try a different router at home.

Thanks again

Ben

[Rik]

I think you're right, Ben, a router swap is the next logical step - even if it doesn't quite make sense still.

[bsmither]

Hi Rik,

One last thing... if I set up an FTP account on the server, do you think that IDNet would test the speed for me from their network?

Thanks

Ben

[Rik]

There's no harm in asking. I'd certainly be happy to test, and I'm sure there would be a few other volunteers here (be aware, though, that I have a 3.5M line).

[Simon_idnet]

Of the two FTP clients that you've used (home and Cambridge) is one multi-threaded (and the other not)? I was just wondering whether the 8Mbps link is comprised of 4 x 2Mbps circuits that are bonded.