I know most people use different MTU speeds but can people advise what seems to be the most common for this setting.

 

Many thanks 

As you say it varies. My old router (Linksys WAG354) defaulted to an auto setting which could be manually changed. I only once had to do this - I set it to 1458 when I experienced a spell of disconnects.

My present router (Speedtouch 585v6) uses 1500.

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Fred

I would first test your download speed here: http://www.speedtest.bbmax.co.uk/

Next, assuming Windows XP, download the SG TCP Optimiser from http://www.speedguide.net and see the Largest MTU setting it recommends for your download speed settings.

Finally, make sure that the router and PC settings are the same, see http://www.kitz.co.uk/adsl/MTU.htm

I just wanted to check my settings as I appear to have lost about one third of my download speed. Have just checked the BT tester and the following results.

IP Profile 3000kbps

4480 download

Actual 2609

 

I used to get about 4500 on a speed test 

 

It is a dual boot system so if I have to change any settings it will have to be on XP Pro and Vista 

Hello,

YES! The whole MTU thing has been driving me crazy recently but I think I finally nailed it. If you want a VERY clear and good explaination about MTU and how to work out what yours should be then take a look at this recommended website

http://www.kitz.co.uk


**TIP, you can use the PING command to test the maximum packet size that can be sent before the packets fragment. Once you know the maximum size you add + 28 for the header and this gives you your MTU value.

**Also note: DON'T worry or even bother trying to adjust the RWIN values for your machine & connection if your using XP or Vista as this is calculated dynamically. Thus trying to adjust it is a total waste of time. Its the MTU and MSS that seems to matter most of all.

**I recommend TCPOptimzer over Dr.TCP its a much better tool. Plus you can also use the Speed Guide website and tweak tester to see how effective your adjustments really are.

PS: my MTU is 1452 on XP and MAX DSL (BT) and zen active 8000 connection. But MTU is very individual to each connection.

Hope that helps? Ivan

I have used the tools, but as stated this is a dual boot system so somehow the settings will have to be replicated to Vista, which is a problem. Studies have shown that my connection is still one third down on what it has been in the past. Looks like I will just have to live with the slower speed. Maybe one day I will manage to figure out what has happened to the connection.