XP & Internet Bandwidth

Wiggins · 18 Jul 2007 at 08:52

Is it me or does XP save a percentage of the bandwidth for stupid things which stops the connection running 100 percent???

If so, is there a way of stopping this so I can be greedy and have it all?

marc2003 · 18 Jul 2007 at 08:59

Wiggins said:
Is it me

yes.

AJUK · 18 Jul 2007 at 09:01

Yes it does, the QoS service.

Turn the service off, it is a complete waste of resources.

http://www.blackviper.com/WinXP/Services/QoS_RSVP.htm

1337z0r · 18 Jul 2007 at 09:03

Depends where your downloading from, If its a normal website the speeds are not going to be great unless they have a decent server and bandwidth. Your pc could have spyware. Best way to check that it's just the site's you go on is to go to www.gamefiles.virginmedia.com and download a file from there and that should max your internet connection's speed.

AJUK · 18 Jul 2007 at 09:05

Download TCP Optimizer and let it work out the best settings for you.

marc2003 · 18 Jul 2007 at 09:17

AJUK said:
Yes it does, the QoS service.

Turn the service off, it is a complete waste of resources.

http://www.blackviper.com/WinXP/Services/QoS_RSVP.htm

i just knew someone was going to post that. it's cobblers.

AJUK · 18 Jul 2007 at 09:19

marc2003 said:
i just knew someone was going to post that. it's cobblers.

Fine, I turned it off when I was using Windows and it made a difference. I don't care either way.

marc2003 · 18 Jul 2007 at 09:24

AJUK said:
I don't care either way.

good for you.

http://support.microsoft.com/default.aspx?scid=kb;EN-US;q316666

Clarification about the use of QoS in end computers that are running Windows XP
As in Windows 2000, programs can take advantage of QoS through the QoS APIs in Windows XP. One hundred percent of the network bandwidth is available to be shared by all programs unless a program specifically requests priority bandwidth. This "reserved" bandwidth is still available to other programs unless the requesting program is sending data. By default, programs can reserve up to an aggregate bandwidth of 20 percent of the underlying link speed on each interface on an end computer. If the program that reserved the bandwidth is not sending sufficient data to use it, the unused part of the reserved bandwidth is available for other data flows on the same host.

Wiggins · 18 Jul 2007 at 09:34

Just ran TCP Optimizer.

MTU was set to 1200 :confused:

Connection speed on this was @ 2000 kbps and I have 8meg although I do lay asleep at night dreaming that BT would send the magic man out to make it a FULL 8meg.

Anyway, I set the MTU to 1500 and the connection speed to 8meg, low and behold the speed has actually increased.

Nice One

Wiggins · 18 Jul 2007 at 09:36

I take it then that the QOS Packet Scheduler reserves this bandwidth for the likes of programs wanting updates etc...

marc2003 · 18 Jul 2007 at 09:42

Wiggins said:
I take it then that the QOS Packet Scheduler reserves this bandwidth for the likes of programs wanting updates etc...

i give up.

edit: to answer the question, no.

bledd · 18 Jul 2007 at 11:16

qos can be used by voip programs, i think skype may use it to get a clear connection, not sure though

richardbirks · 18 Jul 2007 at 11:38

Wiggins said:
Just ran TCP Optimizer.

MTU was set to 1200

Connection speed on this was @ 2000 kbps and I have 8meg although I do lay asleep at night dreaming that BT would send the magic man out to make it a FULL 8meg.

Anyway, I set the MTU to 1500 and the connection speed to 8meg, low and behold the speed has actually increased.

Nice One

The optimal size for MTU on ADSL is 1458... this is the value BT Wholesale use across their ATM backbone.

You'll get good results if you set this on your router and/or network adapter.

--
Richard.

Garyj881 · 18 Jul 2007 at 12:30

Unless youre with AOL and the max would be 1400

.walls · 18 Jul 2007 at 12:36

richardbirks said:
The optimal size for MTU on ADSL is 1458... this is the value BT Wholesale use across their ATM backbone.

You'll get good results if you set this on your router and/or network adapter.

--
Richard.

Really? It's network dependent... that may be the ideal setting for BT Wholesale - not necessarily any other provider...

To check what is good for you:

Code:

ping -f -l 1472 www.google.co.uk

This will work out if you're mtu is 1500 (1472+28=1500 -> 28=IP/ICMP header) - if you get a message saying

Code:

Packet needs to be fragmented but DF set.

, then your mtu is too high - drop it down until you find the maximum size which is good for you.

on the ping command, that's a lower case L, not a 1.

AJUK said:
Download TCP Optimizer and let it work out the best settings for you.

You can do a lot more damage than good if you don't know what you're changing with these tools. a lot of them suggest huge RWINs - which is just ridiculous and will hurt your download. A lot of thought has to go into tcp "optimisation".

richardbirks · 18 Jul 2007 at 14:57

=walls= said:
Really? It's network dependent... that may be the ideal setting for BT Wholesale - not necessarily any other provider...

Unless you're LLU then your ISP is almost certainly peering on BT Wholesale and in which case 1458 is the way to go.

Granted, not everyone uses non-LLU ADSL and cable is an entirely different matter altogether, but as with most things, I think the clue is in the question:

=wiggins= said:
Connection speed on this was @ 2000 kbps and I have 8meg although I do lay asleep at night dreaming that BT would send the magic man out to make it a FULL 8meg.

--
Richard

tolien · 18 Jul 2007 at 15:47

richardbirks said:
Unless you're LLU then your ISP is almost certainly peering on BT Wholesale and in which case 1458 is the way to go.

It's nothing to do with peering or BTw, and everything to do with the ISP's setup (given the traffic is encapsulated in ATM frames between you and the ISP) - 1458 bytes certainly isn't ideal for every ISP, whether they use BTw or not.

richardbirks · 18 Jul 2007 at 22:13

Well this is news to me... but then, I'm certainly not following BT's product offerings these days as I'm no longer working primarily in networking.

Are we saying BT are now offering ISPs (forgetting about ISPs that are LLU and have their DSLAMs in exchanges) alternatives to the L2TP from exchange to ISP backbone? L2TP incurs a packet overhead of 42 bytes, meaning the best that you can hope to achieve (or the best that you could hope to achieve) was 1500 - 42 bytes of overhead, giving you a theoretical optimal MTU of 1458 bytes.

Certainly be interested to know...

--
Richard

tolien · 18 Jul 2007 at 22:51

richardbirks said:
Are we saying BT are now offering ISPs (forgetting about ISPs that are LLU and have their DSLAMs in exchanges) alternatives to the L2TP from exchange to ISP backbone?

DataStream and the 2Mbps IPStream Central never have used L2TP, as far as I'm aware, but they aren't peering arrangements.

L2TP incurs a packet overhead of 42 bytes, meaning the best that you can hope to achieve (or the best that you could hope to achieve) was 1500 - 42 bytes of overhead, giving you a theoretical optimal MTU of 1458 bytes.

The standard L2TP overhead is 40 bytes, last I looked, but the rest is making a lot of assumptions, for starters that the ISP isn't running with a lower MTU on their kit (for example, the Pipex group do/did that) or using PPPoEoA, a la AOL.

Edit: Reading the SINs, BTw set an MTU of 1600 over the L2TP session, so the L2TP overhead is irrelevant anyway, given it disappears in the extra 100 bytes.