mtu/rwin

sobranie · Sep 18, 2009, 20:06:07

Anyone know what the mtu/rwin settings are on an original xp disc please.

Simon · Sep 18, 2009, 20:28:18

Sorry, Rick, I can't find anything definitive, but hopefully, someone will know.

kinmel · Sep 18, 2009, 20:41:10

The Windows built-in client has a default MTU of 1480. RWin is dynamic depending on MTU and MSS

sobranie · Sep 18, 2009, 21:07:25

Quote from: kinmel on Sep 18, 2009, 20:41:10
The Windows built-in client has a default MTU of 1480. RWin is dynamic depending on MTU and MSS

Interesting point here. wan setup on the netgear DG834GV5 refuses to accept any figure above 1458.

Reason I'm asking is that I've been test running a copy of Tune up utilities 2009 and, like an idiot, I let it alter my internet settings for best performance and didn't take a note of what they were before. This has resulted in my speed dropping from 7100 to 6700 (best).
Have had a fiddle with DrTCP but am getting precisely nowhere. jftr I could have sworn my router setting was 1500 when I received it from IDNet some months back. Note, I have not upgraded the firmware on the router.

LesD · Sep 18, 2009, 21:36:38

I found this with a bit about XP MTU and using the registry editor to change it.
Be it on your own head though if you do start editing the registry. Back it up first for sure.

kinmel · Sep 18, 2009, 21:38:42

Quote from: sobranie on Sep 18, 2009, 21:07:25
Interesting point here. wan setup on the netgear DG834GV5 refuses to accept any figure above 1458.

. jftr I could have sworn my router setting was 1500 when I received it from IDNet some months back. Note, I have not upgraded the firmware on the router.

1500 is the recommended Idnet setting

sobranie · Sep 18, 2009, 21:44:36

Quote from: kinmel on Sep 18, 2009, 21:38:42
1500 is the recommended Idnet setting

I will query IDNet on Monday why it's not possible to enter 1500 on the DG834G V5 & will post reply.

LesD · Sep 18, 2009, 21:45:13

Quote from: kinmel on Sep 18, 2009, 21:38:42
1500 is the recommended Idnet setting

I thought so too until I saw reply #8 here!

Steve · Sep 18, 2009, 22:12:53

Quote from: sobranie on Sep 18, 2009, 21:44:36
I will query IDNet on Monday why it's not possible to enter 1500 on the DG834G V5 & will post reply.

This is from the netgear forum

login to telnet (first enable with debug command)

then this command 'ifconfig ppp mtu 1500'

you will have to type command everytime you recconect to isp, this bug is not in the older version of firmware.

Simon · Sep 18, 2009, 22:39:44

Quote from: LesD on Sep 18, 2009, 21:45:13
I thought so too until I saw reply #8 here!

Me too, Les.

sobranie · Sep 18, 2009, 22:41:44

Tks for all replies.
Have set the following pro tem.
RWIN 65535
MTU 1458 on router and 1458 thro. Dr TCP.
Speeds up to 6900+ at the mo.

kinmel · Sep 18, 2009, 22:47:46

Someone, somewhere stated that the correct MTU is 1500, I changed mine to that value when it was recommended.

Now we need to find the culprit

Steve · Sep 18, 2009, 22:53:18

Originally I thought the idea was to leave the router wide open and set the machines individually?

Lance · Sep 18, 2009, 23:24:05

Indeed it was, Steve.

Baz · Sep 19, 2009, 07:54:55

might not help any but I have DG834PN and the setting is at 1500 always has been.I never tried to change it so dont know if it would

sobranie · Sep 19, 2009, 09:29:07

Simon at IDNet has confirmed that 1458 is the best setting on the dg834gv5.

Rik · Sep 19, 2009, 10:59:59

Interesting, Rick. I have tried 1458 and 1500 but get the best results from 1500, with an RWIN of 256960. That's not with a v5, of course.

Gary · Sep 19, 2009, 13:50:04

I tried 1458 as well and the results were not so good, I have a DG834N and have MTU set at 1500 and pages load fine, with MTU set at 1458 some sites took an age to load, including IDnetters

Simon · Sep 19, 2009, 15:51:17

I've switched to 1458, and this morning, it did seem slightly 'snappier' here, but now, I don't really think there's much difference, and it still sometimes takes a second or two to load all the smileys.

Rik · Sep 19, 2009, 16:03:57

I wonder how much we gain from tweaking? When I came to IDNet I was advised to use 1458 or 1500, the latter has always seemed to work best for me. At Nildram, I was using 1430.

Steve · Sep 19, 2009, 19:58:00

When I came to IDnet didn't know what MTU was

Rik · Sep 19, 2009, 19:58:34

Happy days, eh Steve.

LesD · Sep 19, 2009, 20:08:24

Quote from: sobranie on Sep 18, 2009, 22:41:44
Tks for all replies.
Have set the following pro tem.
RWIN 65535
MTU 1458 on router and 1458 thro. Dr TCP.
Speeds up to 6900+ at the mo.

In the link I gave at reply #4 above, immediately above XP specific bit, is the following warning:

NOTE: DO NOT USE DR. TCP ON WINDOWS 2000 & WINDOWS XP.

I am sure that I used Dr TCP with XP Pro but it was sometime ago and my memory fades relatively quickly these days.

Steve · Sep 19, 2009, 22:25:24

I agree Les I too have used it with XP in the past

sobranie · Sep 19, 2009, 22:30:03

Quote from: LesD on Sep 19, 2009, 20:08:24

In the link I gave at reply #4 above, immediately above XP specific bit, is the following warning:

NOTE: DO NOT USE DR. TCP ON WINDOWS 2000 & WINDOWS XP.

I am sure that I used Dr TCP with XP Pro but it was sometime ago and my memory fades relatively quickly these days.

Would sfc /scannow reset things in general do you think Les?

Sebby · Sep 20, 2009, 00:52:45

DrTCP is definitely fine to use with XP.

drummer · Sep 20, 2009, 02:57:00

Maybe I'm going senile, but I think the 1500 MTU recommendation came from experienced forum members, rather than IDNet itself.

TCP Optimizer was also very popular at the time because it actually worked. It also allowed users to change their mind if the recommended options didn't work for them.

I've been using 1500 MTU on the router and all OSs for over two years now and it's never been a problem.

kinmel · Sep 20, 2009, 07:14:51

Quote from: drummer on Sep 20, 2009, 02:57:00
Maybe I'm going senile, but I think the 1500 MTU recommendation came from experienced forum members, rather than IDNet itself.

TCP Optimizer was also very popular at the time because it actually worked. It also allowed users to change their mind if the recommended options didn't work for them.

I've been using 1500 MTU on the router and all OSs for over two years now and it's never been a problem.

You are right, it was all self inflicted and 1500 did prove to be best setting for my ADSL line.

TCP still recommends that I use 1500

Gary · Sep 20, 2009, 08:54:05

having done the ping -f -l 1472 bbc.co.uk test and decreased by 10 untill I do not get get "packet needs to be fragmented" then increased by 1 each time until I am 1 away from that, then added 28 I get 1458 for my MTU, which has lowered my Pings and increased the loading speed of most sites so 1458 is the correct MTU for my line

Steve · Sep 20, 2009, 09:22:52

Tried again myself using DG834N, the wired/wireless Windows machines have no fragmentation at 1472 on my line (if its reporting correctly) I did make the mistake of testing with the router initially set at MTU 1458 and ended being down to about 1435 before the fragmentation stopped. So I think I'll leave it wide open for the present.

Haven't tried on the Macs as I don't know the command

Bill · Sep 20, 2009, 10:51:04

Quote from: stevethegas on Sep 20, 2009, 09:22:52
Haven't tried on the Macs as I don't know the command

I think it's ping -D -s xxxx host (eg ping -D -s 1472 bbc.co.uk) but I'm on an unfamiliar setup here so can't be 100% certain.

That's assuming I've read the info from "man ping" correctly.

Gary · Sep 20, 2009, 14:08:47

Quote from: stevethegas on Sep 20, 2009, 09:22:52
Tried again myself using DG834N, the wired/wireless Windows machines have no fragmentation at 1472 on my line (if its reporting correctly) I did make the mistake of testing with the router initially set at MTU 1458 and ended being down to about 1435 before the fragmentation stopped. So I think I'll leave it wide open for the present.

Haven't tried on the Macs as I don't know the command

I made the same mistake Steve, and 1500 is right for my line, no fragmentation at 1472 either.

LesD · Sep 20, 2009, 16:36:26

Quote from: sobranie on Sep 19, 2009, 22:30:03

Would sfc /scannow reset things in general do you think Les?

I am not familiar with that command I am afraid maybe a Google for it would turn something up.

Despite what I pointed on on the link I posted I am sure Dr TCP worked OK for me in XP so I am sure Sebby is right.

As I recall the Speedguide site never seemed to agree with what I belived I had set though.

Here in Vista as it "Ain't Broke" with my router MTU at 1500 and the Vista default, whatever it is, I am not going to try fixing it!

Especially as I have just obtained this at the Command prompt with no fragmentation:

Microsoft Windows [Version 6.0.6002]
Copyright (c) 2006 Microsoft Corporation. All rights reserved.

C:\Users\Les>ping -f -l 1472 bbc.co.uk

Pinging bbc.co.uk [212.58.224.138] with 1472 bytes of data:
Reply from 212.58.224.138: bytes=1472 time=63ms TTL=122
Reply from 212.58.224.138: bytes=1472 time=60ms TTL=122
Reply from 212.58.224.138: bytes=1472 time=61ms TTL=122
Reply from 212.58.224.138: bytes=1472 time=62ms TTL=122

Ping statistics for 212.58.224.138:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 60ms, Maximum = 63ms, Average = 61ms

C:\Users\Les>

LesD · Sep 20, 2009, 18:14:59

I have had a Google myself for sfc /scannowand found this.

Since it would appear that the MTU is a registry setting I don't think restoring files to their original state would reset the Windows MTU unless anyone knows better that is.

Lance · Sep 20, 2009, 18:42:08

I don't think vista has a default, but instead adjusts dynamically as needed.

Gary · Sep 20, 2009, 19:51:26

Quote from: Lance on Sep 20, 2009, 18:42:08
I don't think vista has a default, but instead adjusts dynamically as needed.

Its meant to but the MTU seems to stay at 1500 if yo type netsh interface ipv4 show subinterfaces into a cmd window and you will see what the settings are, when I changed my Router to 1458 and rebooted Vista did not chage the MTU it remained at 1500

Sebby · Sep 20, 2009, 22:15:47

Quote from: Lance on Sep 20, 2009, 18:42:08
I don't think vista has a default, but instead adjusts dynamically as needed.

That's my understanding, Lance - I remember looking into it when I used Vista. That said, I believe there's a way to make it static and change the value.

Lance · Sep 21, 2009, 06:34:09

I'm sure your right, Sebby, as I remember doing it myself!

wecpcs · Sep 21, 2009, 12:22:11

Quote from: LesD on Sep 18, 2009, 21:45:13
I thought so too until I saw reply #8 here!

After reading that comment from Simon at Idnet, I tried changing mine from 1500 to 1458 and my ping times almost doubled to 76 from a normal 41 and my download speed dropped by half from around 7Mb to 3.5Mb. I immediately changed back to an MTU setting of 1500 on my Netgear DG834G v4 and everything is back to normal again. I will not try that again in a hurry.

Colin

sobranie · Sep 21, 2009, 14:12:28

I wonder if IDNet would swop my almost new V5 for a V4.

Sebby · Sep 21, 2009, 19:31:01

There's only one way to find out, but I'd say probably not.