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Optimising ADSL Settings

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Optimising ADSL Settings

Hi All,

A while ago on the Service status pages there was a message from CS describing how to optimise setting for ADSL,I htink this included Packet Size, Delay Characteristics, MTU??, etc

Unfortunatly I cant find this anywhere now. Can anyone give me a quick idiots guide of what to chnage and where. I know that on the Plus link there was another link to a program to make the changes provided but I am OK with editing the registry settings if someone can give me the path. (Running XP Pro).

Many Thanks
Neil
6 REPLIES
N/A

RE: Optimising ADSL Settings

Most the info you need is here

http://www.adslguide.org.uk/guide/mtu.asp

Angus

missenden
Dabbler
Posts: 14
Registered: 31-07-2007

RE: Optimising ADSL Settings

> Hi All,
>
> A while ago on the Service status pages there was a message from CS describing how to optimise setting for ADSL,I htink this included Packet Size, Delay Characteristics, MTU??, etc
>
> Unfortunatly I cant find this anywhere now. Can anyone give me a quick idiots guide of what to chnage and where. I know that on the Plus link there was another link to a program to make the changes provided but I am OK with editing the registry settings if someone can give me the path. (Running XP Pro).
>
> Many Thanks
> Neil


See recent previous correspondance under subject "Tweaking"

N/A

RE: Optimising ADSL Settings

Thanks everyone for the help.

I'll give it a go.

Cheers
Neil

N/A

RE: Optimising ADSL Settings

Hi Neil,

The announcement that we made a few days ago is no longer available. However I have a copy of the exact message that may be of interest to you:


Dear Customer,

It has been brought to our attention by BT that the ADSL RAS servers route
traffic differently at busy times dependant on the MTU setting used. Several
customers have reported to us that by changing a systems MTU settings an
improvement has been noticed to their ADSL service.

The Internet's Transmission Control Protocol uses the MTU (Maximum
Transmission Unit) to determine the maximum size of each packet in any
transmission. Too large an MTU size may mean retransmissions if the packet
encounters a router that can't handle that large a packet. Too small an MTU
size means relatively more header overhead and more acknowledgements that
have to be sent and handled. Most computer operating systems provide a
default MTU value that is suitable for most users.

In regards to BT's ADSL Network it has become apparent that the optimum MTU
TCP packet size when using DSL over BT in the UK should be 1458. To
administer and change the MTU value on a Windows based PC is quite a
difficult process and should not be attempted unless you consider yourself
to be competent enough to manually edit the registry. We would like to point
out that we are unable to offer support in administering the changes to your
system.

There are utilities available to change MTU values such as drtcp.exe which
is available from: http://www.dslreports.com/front/drtcp.html

We would like to stress that by altering your MTU value is by no means are
sure fire way to resolve all types of ADSL connectivity problems. At best,
altering your systems MTU value will only enhance an existing and fully
functional ADSL connection. If you are not experiencing poor connection
speeds or data transfer rates then we strongly suggest that you do not try
and alter any of your systems MTU settings.

Kind Regards,

Customer Support

--
| David Watson. Unmetered & ADSL solutions
| Technical Support. for Home & Business
| PlusNet Technologies Ltd. @ http://www.plus.net
+ ----- My Referrals - It pays to recommend PlusNet ----- +
N/A

RE: Optimising ADSL Settings

You need to cahnge XP settings as well o rit will hog 20% bandwidth for QOS

Increase BROADBAND:

this ones simple:
this is for broad band connections. I didn’t try it on dial up but might work for dial up.
1.make sure your logged on as actually "Administrator". do not log on with any account that just has administrator privileges.
2. start - run - type gpedit.msc
3. expand the "local computer policy" branch
4. expand the "administrative templates" branch
5. expand the "network branch"
6. Highlight the "QoS Packet Scheduler" in left window
7. in right window double click the "limit reservable bandwidth" setting
8. on setting tab check the "enabled" item
9. where it says "Bandwidth limit %" change it to read 0
reboot if you want to but not necessary on some systems your all done. Effect is immediate on some systems. some need re-boot. I have one machine that needs to reboot first, the others didn't. Don't know why this is.

This is more of a "counter what XP does" thing. In other words, XP seems to want to reserve 20% of the bandwidth for its self. Even with QoS disabled, even when this item is disabled. So why not use it to your advantage. To demonstrate the problem with this on stand alone machines start up a big download from a server with an FTP client. Try to find a server that doesn't max out your bandwidth. In this case you want a slow to medium speed server to demonstrate this. Let it run for a couple of minutes to get stable. The start up another download from the same server with another instance of your FTP client. You will notice that the available bandwidth is now being fought over and one of the clients download will be very slow or both will slow down when they should both be using the available bandwidth. Using this "tweak" both clients will have a fair share of the bandwidth and will not fight over the bandwidth.



> Hi All,
>
> A while ago on the Service status pages there was a message from CS describing how to optimise setting for ADSL,I htink this included Packet Size, Delay Characteristics, MTU??, etc
>
> Unfortunatly I cant find this anywhere now. Can anyone give me a quick idiots guide of what to chnage and where. I know that on the Plus link there was another link to a program to make the changes provided but I am OK with editing the registry settings if someone can give me the path. (Running XP Pro).
>
> Many Thanks
> Neil

espresso_mick
Grafter
Posts: 225
Registered: 30-07-2007

RE: Optimising ADSL Settings

This was a cut and paste job wasn't it. Smiley
I saw this on another thread.

Unfortunately, your wrong m8. You will see NO improvement by having QoS(RSVP) disabled. The FULL bandwidth is available to use for ANY programme unless a QoS enabled application requests bandwidth. Even if you have an application that wants to use the QoS service, if it doesn't use the 20% reserved bandwith, then the unused portion is given back for your system/network to use.

Most people wouldn't make use of this service, and it wouldn't harm your system at home to disable this feature. But, if you want to do it for a speed increase on the net, then you'll be sadly dissapointed.

If you want confirmation from the horses mouth, so to speak. I dug out this from Microsoft.

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