Our BB dilemma

spud17

macman, Any use?

http://surispace.wordpress.com/2007/10/05/expected-speed-on-your-adsl2-connection/

clairet707

penrhyn wrote: »

Your download sync speed is 4.261 Mbps, Line attenuation is 46 db and the noise margin is 15.5db.
With 46db attenuation you should normally expect around 8Mbps, however it looks like your ISP has capped the speed maybe due to noise on the line in the past.
The reason i suspect this is that the router will try and sync with a noise margin of around 7db, the lower the number the faster the sync speed.

Try taking stats again when you experience low throughput to see if the router has reset itself at a lower rate, although I doubt it.

Thanks I think :cool:

Can you say that again though in basic english so I understand :rotfl:

kwikbreaks

Some points after reading through this.

Irrelevant to the OP but "Can you keep the same number if you move your phone calls to Virgin cable - no." is incorrect. You can port a BT number across to VM and it happens immediately when the VM line is installed (or at least it did with me).

Taking VM broadband and retaining a normal phone line is expensive as has already been mentioned. VM charge extra for the BB when no line is taken so you need to do the sums carefully. It could still work out cheaper though as VM call charges are expensive.

There is a Be tool which inteprets SpeedTouch stats...
http://be.nfshost.com/

This is what it has to say about the ones provided (after correcting some dodgy formatting)...

Expected download speed at your current sync rate: 453.30 KB per second (or 3626 kbit)

Expected upload speed at your current sync rate: 95.00 KB per second (or 760 kbit)

Problem: Downstream sync speed of 4261 kbit is 2487 kbit slower or 63 percent of the average for connections with the same downstream attenuation of 46dB.

Problem: Signal Noise Margin Down (15.5dB) is extremely high. Be* may have put you on this profile to compensate for a high error rate. If you know that your line is actually reliable, lowering the value to the average of 6dB should give a sync speed increase. Call Be* to change it (3dB steps only).

Problem: Signal Noise Margin Up (15dB) is higher than average and may be this high in order to compensate for current/previous high error rates.

Problem: Your upstream sync speed of 893 kbit is 83% of the average of 1080 kbit for connections with the same upstream attenuation of 24.5dB.

When I had line problems on O2 the very first thing they did was increase the target noise margin. A total waste of time in my case as I was complaining about audible noise (typical of an HR fault). They also tried to send a new router (unnecessary and they also sent it to the wrong address) Their Tech Support is rather lacking unfortunately. My fault needed an ADSL engineer (5 voice engineers failed to fix it). O2 Tech destroyed my speed, failed to fix the noise (obviously) and were showing no sign at all of being willing to send out BT so I gave up on them and moved to cable.

penrhyn

macman wrote: »

penrhyn, please could you outline how you reach the anticipated Mbps figure from the attenuation and noise margin figures please?
Never quite worked out the relationship between them.

Noise margin is inversly proportional to sync speed, the higher the speed the lower the noise margin.
Most routers will sync at around 7db, thats 7db above the noise on the line.
There are speed vs attenuation/line length graphs about but being lazy I found a handy table,

Attenuation...Approximate Line Length.....Potential Connection Speed
32db.......2.3km.....16000kbps
35db.......2.5km.....14500kbps
40db......2.9km.......11800kbps
45db.......3.2km.........8500kbps
50db........3.6km........6500kbps
55db........4.0km.........4500kbps
60db........4.3km.........3200kbps
65db........4.7km.........2000kbps

clairet707

Wow I really don't want to speak too soon but it looks like my 1h30 on the phone to O2 yesterday has done the trick...

I finally got accelerated to 2nd line support and they did all they could and today forwarded it to 3rd line support

Since I got home tonight I've been getting constant 5Mb speeds down and 1Mb up

New stats as of today

Link Information
Uptime:0 days, 0:12:29
DSL Type:G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]:1,213 / 5,875
Data Transferred (Sent/Received) [kB/kB]:0.00 / 0.00
Output Power (Up/Down) [dBm]:12.0 / 19.0
Line Attenuation (Up/Down) [dB]:24.5 / 46.0
SN Margin (Up/Down) [dB]:6.0 / 7.0
Vendor ID (Local/Remote): TMMB / BDCM
Loss of Framing (Local/Remote):0 / 0
Loss of Signal (Local/Remote):0 / 0
Loss of Power (Local/Remote):0 / 0
Loss of Link (Remote):0
Error Seconds (Local/Remote):0 / 0
FEC Errors (Up/Down):14 / 191
CRC Errors (Up/Down):14 / 0
HEC Errors (Up/Down):211 / 0

:T:eek:

penrhyn

Looks as if o2 have done a good job for you.

Upload 1,213Kbps Download 5,875 Kbps ( almost 6Mbps)

Line Attenuation (Up/Down) [dB]:24.5 / 46.0

Noise margin (Up/Down) [db]: 6 / 7


Assuming those stats were taken from the test socket thats about as good as it gets.

kwikbreaks

All they've done is set the target noise margin nearer to default.

Expected download speed at your current sync rate: 625.00 KB per second (or 5000 kbit)

Expected upload speed at your current sync rate: 129.04 KB per second (or 1032 kbit)

Signal Noise Margin Down (7dB) is higher than average. Be* may have put you on this profile to compensate for a high error rate. If you know that your line is actually reliable, lowering the value to the average of 6dB should give a sync speed increase. Call Be* to change it (3dB steps only).

The average upstream sync speed attained by other users with the same upstream attenuation as you (24.5dB) is 1080 kbit (133 kbit or 12 percent slower than your connection). If you are using Fast Path, then that would explain the increase.

Problem: Downstream sync speed of 5875 kbit is 873 kbit slower or 87 percent of the average for connections with the same downstream attenuation of 46dB.

Problem: High frequency of HEC Up errors (0.28/sec).

Problem: Resubmit statistics in at least 4.79 hours. Ideally more time is needed to say whether any errors were just one-off occurrences.

clairet707

Well a further update, I got a call today from 2nd line, BT engineer is coming to sort the line issue out on saturday morning, what they have done is a temporary fix but the bt guy 'should' fix it permamently on saturday

This morning it was about half what I was getting last night and now it is

penrhyn

You are not comparing like with like, suggest you redo stats and note download sync speed.

clairet707

penrhyn wrote: »

You are not comparing like with like, suggest you redo stats and note download sync speed.

Sorry I dont get you?

Comparing like for like with what?

(sorry its been a long day)