Do NTL shape FTP traffic? Can't get anywhere near my connection speed

Maff · 22-11-2005, 10:04

Hey folks,

I've got the NTL250 modem and i've recently been upgraded to the 10mb service. I'm in Leicester (LE1).

My experiences so far are mixed though. From some websites with good servers, I can very nearly max out the 10mb connection. Others vary significantly, but that's par for the course.

My problem is, I have a friend in Europe who hosts an FTP server to share his creative endeavours. Being in Europe, it's a massively fast server, and it should max out my 10mb connection (it maxes out all his friends, and his).

However, my connection is stuck at 2mb when downloading from it. When i can regularly get 8-9mb speeds in my web browser downloading files, It's puzzling that i can't get the same on an FTP server that has few users and should max it out.

Any ideas on what could be causing it and if i can fix it? Do you think it's NTL shaping the traffic, and if so, can i get around that?

jaycee · 22-11-2005, 15:20

Yes, if you get your friend to run his FTP on another port instead of port 21. They can only recognise FTP traffic sent over the standard ports.

Maff · 22-11-2005, 15:24

It's running on port 4848 at the moment, does that class as a 'standard port' then?

Graham M · 22-11-2005, 15:28

What Upload speed does your friend have?

22-11-2005, 15:46

Quote:

Originally Posted by Maff

Hey folks,

Do you think it's NTL shaping the traffic, and if so, can i get around that?

NTL do not shape traffic.

Chrysalis · 22-11-2005, 18:37

http://www.cableforum.co.uk/board/sh...ad.php?t=36258

Probably going through the congested amsterdam router, if possible can you paste a traceroute to and from the server please so I can see if I am right. You dont have to submit your own ip and the target ip in the trace.

I also have a small thoery that as some congestion seems to only affect part of the country that it could be the route that it takes from Leics and surrounding areas is different to other parts of the country, eg. we go through leeds and if leeds has congestion we might suffer as a result. That I am still trying to investigate.

At times I have thought ntl shape ftp traffic on non standard ports but it is hard to diagnose and my conclusion is I think they dont shape it but rather the issue I mentioned above, it is easy to think this because often a httpd download especially if from a common server will be coming from a proxy server which is on ntl's internal network and will be faster.

Maff · 22-11-2005, 20:47

Quote:

What Upload speed does your friend have?

The server's upload speed is 100mbit.

Chrysalis...

Httpd downloads from the same server come down at 10mb and my friend informs me they are non-cachable files.

fluff · 22-11-2005, 21:40

Use multiple threads when downloading via the ftp

Several clients support this.

Chrysalis · 23-11-2005, 00:16

If you 100% sure the files are non cacheable then I suggest one of the 3 has happened.

1 - ntl proxies ignoring dont cache tag.
2 - ntl are shaping, since I did my tests before the recent changes and I think ntl are at least shaping traffic to improve pings now so may be doing same for http but I just havent tested since.
3 - their is a problem only affecting ftp throughput, sometimes things like send rwin only affect the ftp and not http and they perform different for specific reasons this may or may not be the case I dont know.

If you get a chance do those traceroute's please.

**Paul** · 23-11-2005, 00:48

Quote:

Originally Posted by Chrysalis

1 - ntl proxies ignoring dont cache tag.
2 - ntl are shaping, since I did my tests before the recent changes and I think ntl are at least shaping traffic to improve pings now so may be doing same for http but I just havent tested since.
3 - their is a problem only affecting ftp throughput, sometimes things like send rwin only affect the ftp and not http and they perform different for specific reasons this may or may not be the case I dont know.

1. Unlikely, but possible I suppose.
2. ntl do not currently traffic shape (esp on port 4848 .....)
3. RWIN is a tcp setting, not an http/ftp setting, so it should affect all or none.

Chrysalis · 23-11-2005, 23:21

Well I did some tests on my server again and I noticed all the ftp files were coming out at around 120Kb (1mbit) but fluctuating widly during the transfer.

I did a download over IE and it was going at around 3mbit, I then aborted and retried it using getright, this opened up 3 segments and it was going at around 240kB, I closed of the 2nd and 3rd segments so it was single threaded and it slowed down to around 60kB, so my conclusion is something maybe in IE helps the downloading and it was possibly downloading of a ntl proxy to get the 3mbit speeds. It doesnt appear to be shaping http traffic.

Paul regarding pings I think ntl are doing something to improve them since latency has improved at the same time as throughput dropping, the throughput been so low on a server only 30ms away is a clear sign of congestion and there should be a ton of lag to go with it, if I ping the ntl router from my server using icmp packets they fluctuate wildy but if I ping with udp they are more stable with small fluctuations indicating udp packets are higher priority. I plan to fire of an email to the ntl techs tommorow asking them what the situation is concerning traffic that goes through amsterdam and see if they are planning anything to resolve it. From leaseweb I get slightly improved throughput (around 2-3mbit) this is going through the same router.

**Paul** · 24-11-2005, 00:00

Quote:

Originally Posted by Chrysalis

I ping the ntl router from my server using icmp packets they fluctuate wildy but if I ping with udp they are more stable with small fluctuations indicating udp packets are higher priority.

That isn't traffic shaping, routers have always given lower priority to icmp traffic when they are busy, that's standard.

Ben · 24-11-2005, 07:32

Is your friend on BBB?

AbyssUnderground · 24-11-2005, 08:08

The server you are downloading from might be limiting the connection speed to 60KB/s per connection. Making more connections means higher speed...

Ignition · 24-11-2005, 08:36

As stated above his friends have no issues with downloading at max speed from the server.

Potentially ntl might be traffic shaping however FTP seems an unlikely target if they were planning to traffic shape anything, I'd expect to see P2P feeling the pain first.