Connection Throttling
 

Here's my problem.

If I connect to almost any USA site to download a file, the best average download speed I can get is about 20K bytes/second at any time day or night.

If I segment the download over 4 connections then I can get 70K bytes/second download speed for the same file from the same site. Even at peak times it's only a little slower.

A neighbour of mine who has BT ADSL can download the same file at 64K bytes/second with a single connection.

On UK sites I can get a single connection to download in the 60's.

I don't think the site is throttling as my neighbour can download at a reasonable speed.

I don't think it's local congestion as the segmented download is good and UK sites download fast on a single connection.

I don't think it's my PC as the single connection to a UK site downloads fast.

Am I doing something wrong? Am I being unreasonable about download speeds on the 600K service to the USA?

Other things tried:

With and without Firewall (Zonealarm - no difference)
With and without Anti Virus (McAfee - no difference)
With without spyware detecting/cleaning software (Spybot/SpyBlaster - no difference)

I'm using XP Prof, and have a STB.

Thanks for any help.

Cliff

Re: Connection Throttling
 

Long shot here, but you might find it's a symptom of this XP setting: http://www.tweakxp.com/display.aspx?id=282

On the other hand, it's widely known that the transatlantic links have been less than reliable over the last couple of months. So I wouldn't lose sleep over it if you don't get a fix. ;)

Re: Connection Throttling
 

This sounds as if you need to increase the RWIN setting on your network interface. The longer the end-to-end latency, the larger RWIN needs to be to maintain full throughput. This would explain why you get better throughput from UK sites (low latency) than US sites (with higher latency). Adjusting RWIN is best done by downloading DrTCP from http://www.broadbandreports.com/drtcp.

The QoS features of XP will not help with this problem: they only apply to bandwidth reservation on your network interface for QoS-aware applications, and (a) I'm guessing your applications are not QoS-aware (very few are), and (b) the problem is not a shortage of bandwidth on your network interface, which runs at ethernet speeds.