Confused over 21CN and LLU connections

I am currently looking around seeing what else I can get for my money and hopefully an improvement in speed.

I am currently on a full LLU (CPW - Carphone Warehouse) connection on a long line - best estimate is 5.4Km and usually get 1.7 to 2.01Kbps connection. When I was on an IPstream product a couple of years ago it was about half that.

Doing a speed test with PlusNet or BT I get the following estimate

BT Total Broadband BT Total Broadband
The speed prediction we have provided is an estimate, however download speeds can vary and the actual download speed will fall between a range. This is generally within 1-2 Mb higher or lower than your estimated speed quoted. Between 2.5Mb and 6.5Mb
(Estimated speed: 4.0Mb)

Though this is of course a postcode check.

The stats from my router are

ADSL Link Downstream Upstream
Connection Speed 1723 kbps 498 kbps
Line Attenuation 63.5 db 36.5 db
Noise Margin 12.3 db 11.6 db

So presumably they are quoting for a 21CN connection. Is it realistic that I will see an increase of speed over the current LLU connection.

My exchange is SDMDHRS

My router is a Netgear DGN 2000

Edited by deleted (Sat 03-Nov-12 18:53:55)

No you will get about the same speed, as full LLU from CPW and 21CN use the same technology i.e. ADSL2+

What might change with 21CN WBC is that if the line is stable you may get a 6dB target margin, boosting speed to perhaps 2 to 2.5Meg. If your line is stable you can request this sort of change with TalkTalk via their own members forum

And a range like this is to be expected on the postcode, as this can cover a wide area depending on density of housing.

Thanks for that - didn't think I would get anything magic. BTW I am not with TT, just on a CPW reseller line.

No, both LLU & 21CN use the same technology, ADSL2+. You may gain or lose some benefit from the way diff ISPs handle that technology, like BTw can use a lower NM, 3dB, on stable lines.

In fact at your distance you'd be better off running with ADSL1 or ADSL2 only. You might even be doing that now if you could see the ADSL Mode from the TELNET i/f of your Netgear router.

In which case reseller should be able to make the request

In reply to a post by XRaySpeX:

No, both LLU & 21CN use the same technology, ADSL2+. You may gain or lose some benefit from the way diff ISPs handle that technology, like BTw can use a lower NM, 3dB, on stable lines.

In fact at your distance you'd be better off running with ADSL1 or ADSL2 only. You might even be doing that now if you could see the ADSL Mode from the TELNET i/f of your Netgear router.

Thanks

I do have a few choices as follows:-

Modulation mode
MultiMode
G.DMT
G.Lite
T1.413
ADSL2 (G.992.3)
ADSL2+ (G.992.5)
Reach Ext. ADSL (Annex L)
Double Upstream (Annex M)

At the moment I have ADSL2+ selected but I can have any or all selected. Did have them all selected earlier which was giving a higher speed. Chose ADSL2+ and the speed dropped a bit, but they may have been because I had already rebooted twice today thinking it was at fault rather than a cable.

ADSL2 is probably the best option

I didn't mean what you choose, but what the router negotiated with the exchange kit, which you can only see via TELNET with Netgear routers.

Don't reboot the router frequently. The system doesn't like it. A few times an hour, but well below 10, is permissible, but I used to stick at 5-6 and leave time between them.

For best connection sped, always do the connection well inside daylight hours.

Select ADSL2 and G.DMT. Nothing else. See how that goes.

In reply to a post by MrSaffron:

ADSL2 is probably the best option

Ok - will try that.

In reply to a post by XRaySpeX:

I didn't mean what you choose, but what the router negotiated with the exchange kit, which you can only see via TELNET with Netgear routers.

Can you guide me through that please - foreign territory to me.

Scroll down to the bottom of this page. Just the stats bit. Don't go tweaking!

In reply to a post by RobertoS:

Don't reboot the router frequently. The system doesn't like it. A few times an hour, but well below 10, is permissible, but I used to stick at 5-6 and leave time between them.

For best connection sped, always do the connection well inside daylight hours.

Select ADSL2 and G.DMT. Nothing else. See how that goes.

Thanks Robert

Always on 24/7 and reboot very infrequently. Sometimes it gets its knickers in a twist - don't know if it crashes or what. I am using DGTeam software.

Didn't know about daylight hours - will bear that in mind.

In reply to a post by RobertoS:

Scroll down to the bottom of this page. Just the stats bit. Don't go tweaking!

Presumably that is the same as I can achieve via the DGTeam interface?

Look in here for your router: http://www.kitz.co.uk/routers/netgeardg834_interleav...

@ Roberto: I give this as yours only covers Netgear DG834Gv4, DG834GT, DG834PN, DG834N, DGN2000

EDIT: Ah, I see OP has the last one

Edited by XRaySpeX (Sat 03-Nov-12 20:20:30)

I don't know what stats you can get with DGTeam.

In reply to a post by RobertoS:

I don't know what stats you can get with DGTeam.

I was really referring to the tweaking you can do.

I have tried setting to ADSL2 and although the router shows a connection I cannot load anything via the browser. I have gone back to defaults which selects everything and shows a better speed.

I have tried the Telnet and get the following. There is a page full but am only showing the first few lines. Will show the rest if they are relevant.

# adslctl info --stats
adslctl: ADSL driver and PHY status
Status: ShowtimeRetrain Reason: 8000
Channel: FAST, Upstream rate = 497 Kbps, Downstream rate = 2056 Kbps
Link Power State: L0
Mode: ADSL2
Channel: Fast
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 12.4 12.2
Attn(dB): 62.0 36.6
Pwr(dBm): 0.0 12.9
Max(Kbps): 2584 492
Rate (Kbps): 2056 497
G.dmt framing
K: 60(0) 23
R: 12 10
S: 4 8
D: 16 2
ADSL2 framing
MSGc: 64 10
B: 59 22
M: 4 8
T: 1 3
R: 12 10
S: 3.6721 11.6691
L: 549 133
D: 16 2

In reply to a post by gdavid:

I have tried setting to ADSL2 and although the router shows a connection I cannot load anything via the browser.

There's no reason for this. Those stats show it has chosen ADSL2 whatever you selected.

How about selecting G.DMT, ADSL2 & ADSL2+ in turn and posting those corresponding stats (up to "Rate (Kbps):")?

In reply to a post by XRaySpeX:

In reply to a post by gdavid:

I have tried setting to ADSL2 and although the router shows a connection I cannot load anything via the browser.

There's no reason for this. Those stats show it has chosen ADSL2 whatever you selected.

How about selecting G.DMT, ADSL2 & ADSL2+ in turn and posting those corresponding stats (up to "Rate (Kbps):")?

That's curious - it didn't work on ADSL2 from either computer until I changed it back to ADSL2+.

This is what I had on ADSL2 when the computer would not connect.

# adslctl info --stats
adslctl: ADSL driver and PHY status
Status: ShowtimeRetrain Reason: 8000
Channel: FAST, Upstream rate = 498 Kbps, Downstream rate = 1723 Kbps
Link Power State: L0
Mode: ADSL2
Channel: Fast
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 12.9 11.6
Attn(dB): 63.5 36.5
Pwr(dBm): 0.0 12.9
Max(Kbps): 2200 480
Rate (Kbps): 1723 498

I will re do them tomorrow and post the results.

In reply to a post by XRaySpeX:

In reply to a post by gdavid:

I have tried setting to ADSL2 and although the router shows a connection I cannot load anything via the browser.

There's no reason for this. Those stats show it has chosen ADSL2 whatever you selected.

How about selecting G.DMT, ADSL2 & ADSL2+ in turn and posting those corresponding stats (up to "Rate (Kbps):")?

I have now done the three tests

On G.DMT it connected
ADSL2 I could not connect
ADSL2+ it connected

When I selected G.DMT again it would not connect again. Then tried selecting the three of them and could not connect, but it did after rebooting the router. Maybe I should have done that after each one but selecting "Apply" I thought was doing the same thing.

G.DMT results

# adslctl info --stats
adslctl: ADSL driver and PHY status
Status: ShowtimeRetrain Reason: 8000
Channel: INTR, Upstream rate = 416 Kbps, Downstream rate = 2112 Kbps
Link Power State: L0
Mode: G.DMT
Channel: Interleave
Trellis: ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 12.4 13.0
Attn(dB): 63.0 31.5
Pwr(dBm): 17.3 12.3
Max(Kbps): 2272 532
Rate (Kbps): 2112 416

ADSL2 results

# adslctl info --stats
adslctl: ADSL driver and PHY status
Status: ShowtimeRetrain Reason: 8000
Channel: FAST, Upstream rate = 526 Kbps, Downstream rate = 1996 Kbps
Link Power State: L0
Mode: ADSL2
Channel: Fast
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 12.4 11.3
Attn(dB): 62.0 36.7
Pwr(dBm): 0.0 13.0
Max(Kbps): 2500 528
Rate (Kbps): 1996 526

ADSL2+ results

# adslctl info --stats
adslctl: ADSL driver and PHY status
Status: ShowtimeRetrain Reason: 8000
Channel: FAST, Upstream rate = 495 Kbps, Downstream rate = 1989 Kbps
Link Power State: L0
Mode: ADSL2
Channel: Fast
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 12.5 10.3
Attn(dB): 62.0 36.7
Pwr(dBm): 0.0 13.1
Max(Kbps): 2492 536
Rate (Kbps): 1989 495

Looks like G.DMT is best for you, tho' I would have expected it to be ADSL2. However this is just 1 sample and to be more sure may need more experimentation if you are so inclined. Might even be best to just leave it on Auto and let the DLM choose.

There is still no reason for ADSL2 not to work, particularly since ADSL2+ downgrades to ADSL2.

In reply to a post by XRaySpeX:

Looks like G.DMT is best for you, tho' I would have expected it to be ADSL2. However this is just 1 sample and to be more sure may need more experimentation if you are so inclined. Might even be best to just leave it on Auto and let the DLM choose.

There is still no reason for ADSL2 not to work, particularly since ADSL2+ downgrades to ADSL2.

Thanks

Have gone back to G.DMT and rebooted after applying and is connecting ok and is slightly slower than it was but doubt that will make any difference.

I do note that this is interleaved whereas the ADSL connections weren't

# adslctl info --stats
adslctl: ADSL driver and PHY status
Status: ShowtimeRetrain Reason: 8000
Channel: INTR, Upstream rate = 448 Kbps, Downstream rate = 2016 Kbps
Link Power State: L0
Mode: G.DMT
Channel: Interleave
Trellis: ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 12.9 12.0
Attn(dB): 63.0 31.5
Pwr(dBm): 17.2 12.3
Max(Kbps): 2272 584
Rate (Kbps): 2016 448

I will see how this runs for a few days.

Thanks for your help.

In reply to a post by gdavid:

I do note that this is interleaved whereas the ADSL connections weren't

Too many reconnects in a short time . You are now stuck with interleaving on unless at some time in the future you need a line reset.

There is also the very high noise margin that is being reported all the time. Either some instability in the past, or you caused that as well by doing something similar. Though I would have expected interleaving to have been turned on at the time that was raised.

I don't play games so doubt that will be an issue. It reverted to Fast when I changed to the ADSL connections and may do again if I switch back but I do not see any real difference in the speed of pages loading.

I am on a long line so the noise margin is about what it always is.

Only highly fluctuating noise (I accept there is more chance of that on a long line) causes the margin to rise. There are plenty of long lines with 6dB margin.

Have you dealt with the ring wire for instance?

In reply to a post by gdavid:

I do note that this is interleaved whereas the ADSL connections weren't

Don't place too much faith in those words. Look further down for a line starting "D:" (depth). If it reads

D: 1 1

it's Fast Path; if it's like

D: 64 8

it's Interleaved to a depth of 64 Down.

EDIT: I omitted to ask you for that.

Edited by XRaySpeX (Tue 06-Nov-12 15:39:11)

That's a good point. I'd forgotten that. Netgears in particular report only the upstream words.

In reply to a post by XRaySpeX:

In reply to a post by gdavid:

I do note that this is interleaved whereas the ADSL connections weren't

Don't place too much faith in those words. Look further down for a line starting "D:" (depth). If it reads

D: 1 1

it's Fast Path; if it's like

D: 64 8

it's Interleaved to a depth of 64 Down.

EDIT: I omitted to ask you for that.

I haven't got the ADSL readouts - will leave for a couple days before I try that. Currently on G.DMT is looks like 32:2

# adslctl info --stats
adslctl: ADSL driver and PHY status
Status: ShowtimeRetrain Reason: 8000
Channel: INTR, Upstream rate = 448 Kbps, Downstream rate = 2016 Kbps
Link Power State: L0
Mode: G.DMT
Channel: Interleave
Trellis: ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 12.9 12.0
Attn(dB): 63.0 31.5
Pwr(dBm): 17.2 12.3
Max(Kbps): 2272 584
Rate (Kbps): 2016 448
G.dmt framing
K: 64(0) 15
R: 8 8
S: 2 8
D: 32 2
ADSL2 framing
MSGc: 1 1
B: 64 15
M: 2 8
T: 1 1
R: 8 8
S: 2.1230 8.5000
L: 520 128
D: 32 2

In reply to a post by RobertoS:

Only highly fluctuating noise (I accept there is more chance of that on a long line) causes the margin to rise. There are plenty of long lines with 6dB margin.

Have you dealt with the ring wire for instance?

I thought that a high dB margin was a given on a long line.

At best this is 5.4 to the exchange.

No ring wire - straight off the BT ADSL faceplate.

I have had an oak tree bring my line to the ground and I know there have been a couple of other trees that have fallen across the line. Don't know how much abuse these can take without showing faults. Incidentally how many pairs are there in normal overhead?

I have now changed my router over to a Billion 7700N and found on this thread

http://forums.thinkbroadband.com/dslrouter/t/4061188...

that the SNR can be tweaked (re Roberto's remark) and have now reduced it to 9. I will see if that holds or not over the next few days before trying anything more. Are there any particular stats that I should look out for?

> adsl info --stats
adsl: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 8000
Max: Upstream rate = 448 Kbps, Downstream rate = 2512 Kbps
Path: 0, Upstream rate = 450 Kbps, Downstream rate = 2654 Kbps

Link Power State: L0
Mode: ADSL2
TPS-TC: ATM Mode
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 8.5 11.3
Attn(dB): 63.0 38.7
Pwr(dBm): 17.1 12.8
ADSL2 framing
MSGc: 54 10
B: 29 20
M: 8 8
T: 3 3
R: 10 8
S: 2.8612 11.7333
L: 699 120
D: 16 2

In case it is relevant from the router interface

I

Interface Received Transmitted
  Bytes Pkts Errs Drops Bytes Pkts Errs Drops
LAN1 5067467 28931 0 0 28783452 34977 0 0
LAN2 5893942 63381 0 0 105321464 76669 0 0
LAN3 0 0 0 0 0 0 0 0
LAN4 0 0 0 0 0 0 0 0
wl0 0 0 0 0 3598 32 11 0

Interface Received Transmitted
  Bytes Pkts Errs Drops Bytes Pkts Errs Drops
LAN1 5067467 28931 0 0 28783452 34977 0 0
LAN2 5893942 63381 0 0 105321464 76669 0 0
LAN3 0 0 0 0 0 0 0 0
LAN4 0 0 0 0 0 0 0 0
wl0 0 0 0 0 3598 32 11 0

Edited by deleted (Sun 11-Nov-12 16:35:35)