ATT: Igni and Seph

[Tazz]

Guys I need some advise. Seph you are aware of the problems I am having with the upload on my connection for my 10Mb Broadband on a 50Mb UBR..

Well they say the UBR fault is cleared yet the upload on the connection is still slow... Seph mentioned it could be the MUX unit or something on the VM forums.

Well I was playing with the connection and I remember with my old ADSL connection you could play with the mtu and change it from 1500 to 1478.

Well I was shock to find the following:

1500 MTU: http://www.speedtest.net/result/818769654.png

1478 MTU: http://www.speedtest.net/result/818829610.png

Upload is spot on with 1478 - I did not think this is something that should make a difference on cable?? You guys have any ideas why this makes such a huge difference?

Tazz

[Chrysalis]

sorry if I am the wrong person to reply, if the results are repeatable then I expect it means a router somewhere on your routing is fragmenting 1500 byte packets.

[Tazz]

sorry if I am the wrong person to reply, if the results are repeatable then I expect it means a router somewhere on your routing is fragmenting 1500 byte packets.

No problem any help is good. It looks that way... If i put it back to 1500 the upload goes slow again... back to 1478 fast again. :confused:

[pip08456]

Just use the following. Sorts it automatically

http://www.speedguide.net/downloads.php

[pabscars]

I would be interested in seeing how your connection behaves using the lower MTU, I've had a play with mine numerous times but it doesn't seem to make any difference.

[Sephiroth]

Guys I need some advise. Seph you are aware of the problems I am having with the upload on my connection for my 10Mb Broadband on a 50Mb UBR..

Well they say the UBR fault is cleared yet the upload on the connection is still slow... Seph mentioned it could be the MUX unit or something on the VM forums.

Well I was playing with the connection and I remember with my old ADSL connection you could play with the mtu and change it from 1500 to 1478.

Well I was shock to find the following:

1500 MTU: http://www.speedtest.net/result/818769654.png

1478 MTU: http://www.speedtest.net/result/818829610.png

Upload is spot on with 1478 - I did not think this is something that should make a difference on cable?? You guys have any ideas why this makes such a huge difference?

Tazz

First - to knock the MUX unit thing on the head! I merely speculated where there might be a common cause issue if the two of you in Bracknell were on the same MUX. I cannot diagnose to that granularity via the forums.

On the MTU size, I recommend you read these two items and see if any of the issues applies to your case - :

http://homepage.ntlworld.com/robin.d.h.walker/cmtips/tweaks.html
http://www.internetweekly.org/llarrow/mtumss.html

You can use NETSTAT -S to look at packet fragmentation at each of your MTU settings.

Frankly I wouldn't expect a lowering of MTU to improve Upstream. Speedtest.net would need to be successively tested in rapid succession for each of your MTU cases so as to eliminate (if you ever can) the minute-by-minute variances of the internet.

Also don't ignore Chrysalis' point. It might even go as far as a residual setting somewhere from the past when you were connecyed toADSL - if that ever was the case.

[Tazz]

First - to knock the MUX unit thing on the head! I merely speculated where there might be a common cause issue if the two of you in Bracknell were on the same MUX. I cannot diagnose to that granularity via the forums.

On the MTU size, I recommend you read these two items and see if any of the issues applies to your case - :

http://homepage.ntlworld.com/robin.d.h.walker/cmtips/tweaks.html
http://www.internetweekly.org/llarrow/mtumss.html

You can use NETSTAT -S to look at packet fragmentation at each of your MTU settings.

Frankly I wouldn't expect a lowering of MTU to improve Upstream. Speedtest.net would need to be successively tested in rapid succession for each of your MTU cases so as to eliminate (if you ever can) the minute-by-minute variances of the internet.

Also don't ignore Chrysalis' point. It might even go as far as a residual setting somewhere from the past when you were connecyed toADSL - if that ever was the case.

I only mentioned the MUX in case it was relavent :confused:

I have never changed any MTU settings on my computers when on ADSL on at router level so it wont be anything to do with that. It is also funny how it suddenly happened when I was moved to the 50Mb ubr...

I have done lots of testing with changing the mtu values anything above 1478comes back with packet loss on speedtest.net with slow upload anything below is fine. It has confused me loads.

Anyway I got a call from the CEO office and told him my findings and he will pass it onto the network engineers to look into. However enough was enough and tonight I am being migrated back to a legercy UBR... VOIP and gaming is impossible.

[Chrysalis]

funny that for you legacy beats overlay and for me overlay beats legacy. :)

I know mtu fragmentation can defeitly affect upload speeds because on my adsl connection a 1478 mtu is faster on uploads than 1500byte.

given your results here I may test 1500 bytes on my mtu to see what affect it has as I am still on 1478.

[Tazz]

Was migrated back to the legacy network network last night from rdg-22 to rdg-2 the same ubr before I was moved to the ovelay. Unfortunataly this suffered from DL speed probs back when I was on it however what I was moved at 9pm speeds were good had a slow down at 11:30pm ish but upload is good and I can browse again (at the correct 1500 mtu) :)

I will monitor it over the next few days and if it is still really slow I will e-mail my contact in the CEO office again...

[Sephiroth]

Was migrated back to the legacy network network last night from rdg-22 to rdg-2 the same ubr before I was moved to the ovelay. Unfortunataly this suffered from DL speed probs back when I was on it however what I was moved at 9pm speeds were good had a slow down at 11:30pm ish but upload is good and I can browse again (at the correct 1500 mtu) :)

I will monitor it over the next few days and if it is still really slow I will e-mail my contact in the CEO office again...
This is pure speculation on my part - but if I recall correctly the VM 2nd line support said there was a problem on rdg-22 and provided a ticket number. Packet fragmentation? i.e. a configuration setting?

[Tazz]

This is pure speculation on my part - but if I recall correctly the VM 2nd line support said there was a problem on rdg-22 and provided a ticket number. Packet fragmentation? i.e. a configuration setting?

Yup except they said this had been sorted... if anything it was worse... back on the legacy network so far today so good. ;)