Broadband TCP tweaking

[danrok]

Found this site which tests your connection and helps you to tweak TCP settings.

http://www.dslreports.com/tweaks

[robbie]

Sweet, happy tweaking!!
Rob

[Daniel ~]

A great site! I rush right over yesterday as soon as Comcast sent me an E-mail telling me they had just DOUBLED my bandwidth for free!!

Now smokeing in at 3.3 Mbits":O}

[Áedán]

I've always found that TCP tweaking nets me no performance increase. I've tried on both 8Meg and 512K lines.

If your internet connection is lossy, then some of the parameters can be tweaked to help reduce the impact of the lossy line. On the other hand, if you have a good line, you'll impact performance.

[danrok]

Originally Posted by Daniel ~

A great site! I rush right over yesterday as soon as Comcast sent me an E-mail telling me they had just DOUBLED my bandwidth for free!!

Now smokeing in at 3.3 Mbits":O}

Lucky you!

[danrok]

Originally Posted by Áedán

I've always found that TCP tweaking nets me no performance increase. I've tried on both 8Meg and 512K lines.

If your internet connection is lossy, then some of the parameters can be tweaked to help reduce the impact of the lossy line. On the other hand, if you have a good line, you'll impact performance.

Damn! Don't tell me I've made my line slower. All I changed was the "Receive Window (RWIN)" setting from null to 5840.

[danrok]

I have tested it and my upstream is 53.8KB/s, downstream is 27.0KB/s. I think that's OK.

[Áedán]

You mean your downstream is 53.8Kbyte/sec and your upstream is 27.0Kbyte/sec I hope!

For those in the UK, ADSLGuide have a speed tester that doesn't require a transatlantic trip.

[danrok]

Yes, other way round of course!

[danrok]

I have noticed that if i use my upstream heavily all day my ISP reduces the upstream speed by 50%, as reported by my ADSL router. My mates have observed this too. It must be intentional - i have been monitoring it for some time. I can force it to reconnect at the correct speeds by powering off the router for 20mins.

[Áedán]

What upstream speed do you expect to see, and what do you get?

The ISP doesn't usually have that much control over the speed of the ADSL line - BT provides that leg, and usually charges to regrade speeds.

[danrok]

Currently, the speed is fine. But yesterday the upstream was connected at 198 instead of the 256 I am paying for. I forced it to reconnect at 256 by switching my ADSL router off. The speed only drops when I am using p2p or playing online with many other players, say 20 or more.

In the case of online gaming this causes the game to become unplayable - I have to swtch the router off for a good while and then rejoin the game.

I live in Jersey so this has nothing to do with BT. Jersey Telecoms own all the telephone infrastructure on the island and my account is with them.

Side note: Most traffic is routed out of the island to France, we have a fat power cable which hooks us up to the French national grid - when they laid this cable they had the foresight to include fibre optics with it.

[Daniel ~]

Comcast claims to limit the speed for "excessive usage" But they never have for me.. Mostly I think it's to discourage users from running web servers that hurt the next guy's bandwidth.

[Kaitain]

Do Jersey Telecom get their network hookup through BT or PTT France? It sounds almost as if JT's deal with whichever company provides the connection to the rest of the world is quite highly contended.

[Gizmo]

In my limited experience with this, I've found that Windows2K and WindowsXP both do a pretty good job of adapting to the network automatically. If you start hard-coding settings like this, you take that adaptive characteristic away.

[danrok]

Here's the route my connection follows:

[Áedán]

It looks a roundabout route from Jersey to France to London to USA (probably New York). Opentransit are owned by France Telecom, and have their own global network. However, your data hops across to Abovenet to get across the Atlantic!

Dropping from 256Kbit to 192Kbit shouldn't make the game unplayable though. I would take the issue up with your ISP. It might be that the ADSL equipment is having difficulty transmitting your data, and hence drops down in speed to try and make the connection more reliable.

[danrok]

Originally Posted by Áedán

It might be that the ADSL equipment is having difficulty transmitting your data, and hence drops down in speed to try and make the connection more reliable.

You could be right. But, I see this happening on friends lines as well. Also, when I used to use dial-up this line was always of good quality, the modem would connect at the best possible speed you could expect.

It's difficult to get the ISP to respond to any technical issues.