MTU settings for wireless routers.

I have a draytek Vigor 2600we wireless router, and was wondering about
how to tweak the MTU settings for best effect (I like to tinker...)

Anyway, I read that the best MTU for a UK broadband connection is 1458.
so I changed the router to use this MTU settings.

However, I then started wondering... There is also a MTU setting in the
windows registry for each connection. IMy desktop and laptop both
connect to the router via the wireless interface. How do I tweak these
MTU settings. Should they be also set to 1458?

I did the ping -f -l <routerIP> test, and I did not get unfragmented
packets until I went down as far as 1272 (which I believe is a MTU of
1300). Is this normal for a wireless LAN? Both my desktop and laptop
gave identical results in this test.

I suppose my ultimate questions are:

Is 1300 an unsual MTU for a wireless connection?
Is 1458 the nominal MTU for UK ADSL connections?
Can these (and should these) MTU settings be set independantly?

Thanks. All...

Zapp Brannigan wrote:

> I have a draytek Vigor 2600we wireless router, and was wondering about
> how to tweak the MTU settings for best effect (I like to tinker...)
>
> Anyway, I read that the best MTU for a UK broadband connection is 1458.
> so I changed the router to use this MTU settings.
>
> However, I then started wondering... There is also a MTU setting in the
> windows registry for each connection. IMy desktop and laptop both
> connect to the router via the wireless interface. How do I tweak these
> MTU settings. Should they be also set to 1458?
>
> I did the ping -f -l <routerIP> test, and I did not get unfragmented
> packets until I went down as far as 1272 (which I believe is a MTU of
> 1300). Is this normal for a wireless LAN? Both my desktop and laptop
> gave identical results in this test.
>
> I suppose my ultimate questions are:
>
> Is 1300 an unsual MTU for a wireless connection?
> Is 1458 the nominal MTU for UK ADSL connections?
> Can these (and should these) MTU settings be set independantly?
>
> Thanks. All...
I don't know about the UK. In USA, 1500 is fine for cable modem. For
ADSL, should lower it to 1492.

Two things....BT have in the past suggested 1458 as the optimum
and
I suppose if you set each PC to 1458 then it becomes unnecessary to set the
router doesn't it, since no packets arrive at the router greater than 1458.
(just a thought)

P

"Zapp Brannigan" <(E-Mail Removed)> wrote in message
news:fNrBb.19296$(E-Mail Removed)...
> I have a draytek Vigor 2600we wireless router, and was wondering about
> how to tweak the MTU settings for best effect (I like to tinker...)
>
> Anyway, I read that the best MTU for a UK broadband connection is 1458.
> so I changed the router to use this MTU settings.
>
> However, I then started wondering... There is also a MTU setting in the
> windows registry for each connection. IMy desktop and laptop both
> connect to the router via the wireless interface. How do I tweak these
> MTU settings. Should they be also set to 1458?
>
> I did the ping -f -l <routerIP> test, and I did not get unfragmented
> packets until I went down as far as 1272 (which I believe is a MTU of
> 1300). Is this normal for a wireless LAN? Both my desktop and laptop
> gave identical results in this test.
>
> I suppose my ultimate questions are:
>
> Is 1300 an unsual MTU for a wireless connection?
> Is 1458 the nominal MTU for UK ADSL connections?
> Can these (and should these) MTU settings be set independantly?
>
> Thanks. All...


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In message <fNrBb.19296$(E-Mail Removed)>, Zapp Brannigan
<(E-Mail Removed)> writes

>I have a draytek Vigor 2600we wireless router, and was wondering about
>how to tweak the MTU settings for best effect (I like to tinker...)

[]

Some Draytek Vigor 2600 users have reported an MTU problem:

<http://draytek.co.uk/forum/viewtopic.php?t=2482>

Basically, the Vigor will change back to its default MTU of 1442 and
this can happen anytime from a few minutes to a few weeks. This means
it's pointless setting your PC's MTU to anything greater than 1442. I
have found that an MTU of 1430 gives me good down/up speeds.

I don't know if this affects the 2600we too.
--
Steve Thomas

Zapp Brannigan wrote:

> I have a draytek Vigor 2600we wireless router, and was wondering about
> how to tweak the MTU settings for best effect (I like to tinker...)
>
> Anyway, I read that the best MTU for a UK broadband connection is 1458.
> so I changed the router to use this MTU settings.
>
> However, I then started wondering... There is also a MTU setting in the
> windows registry for each connection. IMy desktop and laptop both
> connect to the router via the wireless interface. How do I tweak these
> MTU settings. Should they be also set to 1458?
>
> I did the ping -f -l <routerIP> test, and I did not get unfragmented
> packets until I went down as far as 1272 (which I believe is a MTU of
> 1300). Is this normal for a wireless LAN? Both my desktop and laptop
> gave identical results in this test.
>
> I suppose my ultimate questions are:
>
> Is 1300 an unsual MTU for a wireless connection?
> Is 1458 the nominal MTU for UK ADSL connections?
> Can these (and should these) MTU settings be set independantly?
>
> Thanks. All...

AIUI the 1458 was to workaround a BT problem which is now fixed and was
never the optimum for users.

1478 is probably best alot like 1430 but if your router forces you lower
count down from those in 48's so you fill ATM cells.

I know nothing about wireless, but would test by pinging internet addresses
as well as just router or have a look on
http://www.speedguide.net/analyzer.php to see MTU.

It's best to set on all clients with Drtcp if you can.

Andy.