topic Re: Expecting higher throughput speed...15mb on ~20mb line in Archive

Expecting higher throughput speed...15mb on ~20mb line

paulthack — Mon, 16 May 2011 11:09:51 GMT

I have recently regraded to the "up to 20mb" service, as my local exchange was enabled end of March 2011.

During the initial 10 day settling in period I had issues with an old router, and having to reconnect, bought a new router which kept losing wireless, and then finally settled on a netgear dg834 which has now been stable for 13 days or so. On day 10 I asked BT to reset my profile due to messing about with routers, and they obliged with a "SNR reset".

Since then I have not unplugged or moved the router apart from once to install an "i-plate".

However I'm not sure if I am getting the best result possible?

When I was on an 8mb connection I was seeing the full 8mb throughput, the router never resynched, and the connection never dropped, which says to me I have a good quality line and a fairly short connection to the exchange (its about 1 mile).

My router stats:

DownStream Connection Speed	18991 kbps
UpStream Connection Speed	966 kbps

Connection Speed	18991 kbps	966 kbps
Line Attenuation	22 db	6 db
Noise Margin	3 db	6 db

I noticed that the noise margin dropped to 3db from 6db about a week after the SNR reset...

Speedtester.bt.com is showing that I am on a 15000 IP Profile. I can get a download speed of around 15.6mb.

I noticed in the router that my line is also set for "interleaved" rather than "fast path".

Based on me being able to get the full 8mb on an 8mb service previously, should I be able to get a higher profile/speed/throughput/synch rate? I know the IP profile is set less than the synch speed, but a whole 3mb less? Is that right? Anything I can do to get more out of the line?

Thanks

Re: Expecting higher throughput speed...15mb on ~20mb line

MHC — Mon, 16 May 2011 16:52:06 GMT

18991 sync would normally mean a 16000 profile - one step above your current 15000.. !9296 is teh point where a 17000 profile comes in - and some tweaking and tidying of your wiring might achieve that.

There could be unseen resyncs caused by an occasional noise event that is keeping your profile at that level - try using Router Stats Lite to monitor the connection for 24/48 hours. RSL will recond SNR margin and Sync speed (up and down) for a large number of modems.

3dB does suggest you have a reasonably stable line - before moving to VDSL (Infinity) I had 3dB for about 15 months - so nothing to worry about.

Re: Expecting higher throughput speed...15mb on ~20mb line

paulthack — Tue, 17 May 2011 09:43:56 GMT

Yes it seems that last night, my 10day training period was over, and having restarted the router I am now on a 16000 profile.

Is this likely to be the best I will get then? I know it's twice my previous speed but maybe being a bit over optimistic I had hoped that as I got a full 8mb previously I would get nearer the 20mb on my line.

Would dropping interleaved and using 'fast path' be an option for a bit more throughput, or is my synch rate the highest it will ever synch at, and im basically never going to get any faster?

Re: Expecting higher throughput speed...15mb on ~20mb line

MHC — Tue, 17 May 2011 15:48:59 GMT

A false hope that you may get a full 20Mb throughput. I have come across some installations where moving from Max to ADSL2+ has resulted in a drop in throughput or just a minimal increase - there are a lot of factors that can affect the speed.

Dropping Interleaving and going to Fast Path will give a small increase BUT there is less error correction so whilst your headline rate is greater, the actual throughput could be lower. I would be happy to stay with a stable line rather than one which resyncs frequently.

Just monitor you line stats for a few days and see what happens particularly on the error count. DO you have a 2700HGV router? There is plenty of line information available on that.

Also, if te system sees you stable for a while (period unknown) your SNR margin may drop to 3dB which will give may give you a step up to teh next profile.