Wireless, how to improve....

Hi guys, I am a new user here so hello to you all . I have a number of questions, I was not sure whether to put them all in "General" or spread the love around
Situation is we have just got BT infinity (Woohoo!) I use a linux (openSuse) PC upstairs (3 bed semi, not big, so distance travelled by the WiFi is only say 15m) the FTTC comes in downstairs, my familiy's Win XP PC is there. I connect via a USB wireless adapter, a hawking dish http://www.amazon.co.uk/Hawking-Hi-Gain-Wireless-G-S... (wireless g)
Also connected to wireless is an all-in-one printer/scanner.
The family PC downstairs gets good DL speeds, with the BT tester often near the max configured speed of 37Mb (cabinet is AFAIK at the top of the Street, < 100m away)
Query is: If I boot my PC upstairs to my usual OS opensuse I get around 10-11 Mb download.
If I boot it to Windows XP I get 16-20Mb Can anyone explain why this might be?
If I upgrade to a wireless n adapter, would I get better speeds upstairs? Would the BTHomeHub default back to wireless g by the presence of the printer scanner on the network?
Is there a tool to measure throughput over the WiFi end alone?
When the engineer came to install he found that the HomeHub 3 sent was faulty, so he installed a HomeHub2. Am I missing any benefit? Should I contact BT to ask for a new HomeHub?
More dumb questions coming your way soon, I am sure.. Until then Ta for reading...

The difference will most likely be the configuation of the TCP stack in Linux, i.e. RWIN and MTU
It may be the drivers in linux for that card are not very good.

Given G is never going to provide 37Mbps, then the best bet is to get everything onto N i.e. connect the printer scanner via a cable

Wow! Thanks for the quick reply... You think wifi n would improve things? Could you point me to some info re. the TCP stacks RWIN/MTU settings or should I ask in a Linux forum?

Presume Family XP PC is Ethernet wired to router?

Try Linux forums for advice on IP parameters.

Ok, so I have delved in to the mysteries of MTU.... I am not much the wiser
I have discovered that if I ping at 1464(1492) it's OK, and at 1465(1493) it frags. I have accordingly set my MTU to 1492. No difference in speeds so far but a little knowledge gained... (a dangerous thing?)
Of now to the find out what RWIN is; does; and how I tweak it.....

Here's a program for viewing and tweaking your TCP paras in XP : SG TCP Optimizer

Perhaps it will help decide values for Linux?

TY Xray....
I have so many variables ATM that I am just tinkering about... I will shutdown and boot to XP and have a look around there.
And yes the family PC is wired to the router. I must check if any neighbours etc are using the same channel as well, which might give some wireless probs. (Dunno how in linux )
Deffo a diff in performance <> win and linux with my wireless set up. Unf I have no kit laying about to compare. My other USB dongle is "loaned" to ex-gf along with laptop, (never see them again) and the other one (Netgear WPN111) REFUSES to work with linux, despite carrying the the same chipset.

Dang and blast forgot that forum login and passwords are different..... so can't login here from XP (pen and paper still useful hmph)
But speeds are deffo better from windows ...... off to try XRAY's suggestion.

Hi,

If your OpenSuse is reasonably up to date I was under the impression that linux kernel TCP/IP stack was self-tuning. Certainly we've never needed to do any tuning at work (100M internet).

MTU is normally discovered and monitored automatically, both in Windows and Linux so I'd be surprised if it were that. (PMTUD)

I'd be wary about hard-coding any values for MTU / RWIN if this prevents any self-tuning for network adapters, especially on wireless which needs to adapt to different networks it connects to (less important in your case as it's not a laptop).

If you could get hold of a long ethernet cable it would be better to test OpenSuse's speed on a wired connection.

It may be down to the the wireless driver (and the USB driver if it's a USB adapter). For example before 'n'Wi-Fi came along, some manufactures had different (proprietary) enhancements for 'g' (Super G etc) which might only be present in the XP driver.

Other factors might be the version of Flash or Java in OpenSuse. If you have the Adobe Flash plugin try TBB's Flash-based tester too.

But as other posters mention, 'g' Wi-Fi may struggle to get much above 24M (even in the same room).

Finally are you certain nothing else was downloading (e.g. updates) when you were running the tests?

If you are happy with the internet connection generally it might be better to test your wi-fi by transferring files back and forth between two machines over the local network. TBB's test files are also suitable to this.

In reply to a post by wakou222:

Ok, so I have delved in to the mysteries of MTU.... I am not much the wiser
I have discovered that if I ping at 1464(1492) it's OK, and at 1465(1493) it frags. I have accordingly set my MTU to 1492. No difference in speeds so far but a little knowledge gained... (a dangerous thing?)
Of now to the find out what RWIN is; does; and how I tweak it.....

Hi, I learnt how to configure the MTU and RWIN settings from Broadband Reports website.
I use the RWIN that DrTCP gives.

http://www.dslreports.com/faq/5793

http://www.dslreports.com/faq/8159

http://www.dslreports.com/faq/9739

Edited by deleted (Fri 04-Mar-11 13:24:18)