Noise Margin Question

[spcdust]

*****SEE ATTACHED IMAGE FOR MY LINE STATS ******

Well I got connected yesterday on the Max service but I'm seeking advice on my stats.

Based on my line attenuation I think I should be achieving anything between 10MB - 14MB, and as you can see from my stats (see the attached image) the line seems to be syncing at 13394 kbps download. HOWEVER, no matter what speed test I do the best I seem able to achieve is around 6MB. It could obviously be many factors but I'm unsure if my Noise Margin has any bearing which is around 6.9db - is higher better or lower best?

Also, BT's MAX ADSL has the 10 day training period, is this the same for LLU ADSL2+?

I would appreciate someone more knowledgeable on Noise Margins and such offering me some insight.

Cheers

Nathan

[hugsie]

ftp.mirror.ac.uk//edunfs/mirrors/sites/ftp.freebsd.org/ftp/pub/FreeBSD/releases/amd64/ISO-IMAGES/6.1/

I just wrote a big long reply and accidentaly pressed back!, while I re type it, try a DL from this FTP, and let us know how you get on!

[stevelondon]

Hi take a quick look here

[hugsie]

http://forums.whirlpool.net.au/forum...fm/567976.html

OK this is a thread from an Austrailian Forum, regarding Low SNR on ADSL2+, I am not sure how useful it will be, but it indicates that lower syncing is normal for ADSL. I recall reading some where (not necessarily in this thread) That ADSL 2+ has no bedding in period as such. Rather each time you reboot your modem negotiates with the exchange asking for the highering the sync speed during the negotiation until the sync speed reaches the target. I think this is about 7 for ADSL 2+. This process occurs with every reboot.

This is why you have to contact your ISP if you are getting instability due to a low SNR as they chan set the SNR target higher and you will loose some speed but get a more stable conncetion.

[spcdust]

Cheers for the links guys, I'd actually had a read of them last night when I Googled the subject - but I'm still a bit unclear what the answer is.

If I'm reading it correctly (and I possibly am not) then my noise margin figure is in the right zone for a good fast ADSL2+ connection and should be in that 10MB-14MB zone for downloads (I suspect 10MB-12MB is more likely). Pretty sure I'm not getting line drop-outs but how are these reported on the Sky Netgear router? Also couldn't find an entry for CRC errors, are these reported as something different on this router.

I'm not loosing sleep over it but just want to get my head around it so if I do eventually decide to take it up with Sky's technical department I know what I'm talking about.

Your further wisdom is always welcome and if anyone else cares to take a look at my stats in the original post I'd be much appreciative of their input?

spcdust

@hugsie
I'll do a download from that ftp link when I get home tonight and report back as I'm not that trustful of any of the online speed test I've done since going onto ADSL+2.

[hugsie]

Have you tried downloading from the FTP? The vast majority of speed tests do not give accurate readings on 10 meg plus. I had a very stable 10 meg connection with cable and only ever saw it maxed by bit torrent news groups or FTP.
I could do a 10 meg dl through one of these and then shut them down and run a speed test and get 6megs.

Have you tried this one? You have to disable norton if you use it as your firewall.

[OhNoes]

hugsie is right, if you want a good show of what your speed is use ftp mirrors - but remember not to stick to just one, since it might be bad routing etc. it's also a good way of testing what kind of speeds you get overseas.

http://www.debian.org/mirror/list

I would recommend some .NL ones after you've tried GB.

[spcdust]

Originally Posted by hugsie

Have you tried downloading from the FTP? The vast majority of speed tests do not give accurate readings on 10 meg plus.....

Yep, planning to do this when I get home via my FTP client. I'm a Mac user and use Transmit so I suppose it's best to report back the data transfer rate which will be KB/s. If you check back on this thread later this evening I'll report some results back and will welcome your comments.

cheers hugsie & OhNoes

spcdust

[spcdust]

Hunting around the net to see if the Sky Netgear DG834GT reported errors I found this potentially handy link:

http://www.gatago.com/uk/telecom/broadband/7190300.html

Which in turn lead to this link:

http://www.suburbia.com.au/~dan/

Apparently to get these additional statistics you have to go into the routers shell at this address on the DG834GT/GTB:

/usr/sbin/adslctl info --stats

Quoting from the suburbia.com link, to get access to the shell you have to:

Getting Shell Access

Getting shell access is surprisingly simple once you know how. It was very frustrating looking at /etc/rcS and seeing utelnetd commented out. However after some time looking through the CGI binaries I noticed the debug keyword near the logout word. You can also see the way logout is used by the web interface. So after using http://192.168.0.1/setup.cgi?todo=debug I tried telnet to 192.168.0.1 and what do you know you have root. No password, nothing. I haven't carried out a portscan to see if any other services such as tftpd are enabled but the service does not appear to be running. Hopefully it should be possible to add a password by modifying /etc/passwd. There doesn't seem to be an /etc/shadow even though it appears to be enabled in the source config.

Not sure if this works on the Sky version, I'll hopefully try tonight but if anyone fancies trying it out....

spcdust