Mtu

[Brian69]

There is an interesting thread over on the O2 sister forum about MTU settings. I find that with Sky 1478 seems to work best (I use Vista). Has anyone any throughts on this?.
I leave the router at 1500 as changing this as well makes no differance.

[dms05]

Brian69 - I thought Vista set MTU automatically and unlike changes in XP you couldn't make Persistent changes to MTU in Vista. Or has someone found a way? A link to the thread you mentioned might be useful.

[TheWhizzz]

here it is m8

MTU - Maximum Transmission Unit - O2User - Unofficial help and support

[dms05]

TheWizzz - nice thread. I've also found out about using 'netsh' to determine MTU values and 'store=persistent' to keep them. It was set at 1500 on Vista and I can see various alternatives suggested. I've tried a few and can't see a lot of difference (if any). I tried 1472 (ie 1500-28) and 1430 on the basis that a slightly small MTU is a whole lot better than a slightly big MTU (which means Packets have to be split and uses bandwidth poorly).

The only time I ever saw a real difference was with AOL when you needed a very low figure (can't remember what it was but it was low).

[Isitme]

I thought Vista set MTU automatically and unlike changes in XP you couldn't make Persistent changes to MTU in Vista.

It is automatically set to 1500, but you can change it. Here's how-
::. Kitz - Vista MTU .::

You can also change the RWIN but it involves turning off auto tune, which Vista does pretty well, so there is not much point.

[Saturday]

Originally Posted by dms05

The only time I ever saw a real difference was with AOL when you needed a very low figure (can't remember what it was but it was low).

Most PPPoA networks around the world are set up for a MTU of 1500. Sky LLU and Connect (BT IPStream) are both PPPoA.

AOL once used PPPoE and this had a MTU of 1400 or 1438 depending on the version, if I recall correctly. I don't think they're PPPoE in the UK any more as I assume they're now BT IPStream, but could be wrong, I'm not too clued up on AOL.

BTW, if anyone is interested, O2/Be use ETHoA for LLU