Some tech questions

Hi guys,

I am currently on the talktalk LLU up to 8meg service and was hoping people could confirm whether or not the following info is correct:

1) Talktalk LLU means they have put their own DSLAM in the exchange and have their own cables going from the exchange to their premises therefore bypassing BTs backhaul network

2) All of talktalks DSLAMs are ADSL2+ up to 24mb capable

3) These DSLAMs are however also capable of ADSL1 which is the "mode" in which they work if you are on their regular up to 8mb service

4) Signing up to their speed boost option merely causes the DSLAM to work in it's ADSL2+ "mode" instead of ADSL1

5) Talktalk say your line needs to be capable of 8mb if it is to be eligible for the speedboost simply because it implies you are using their LLU equipment rather than BTs because talktalk don't offer a up to 8mb service on non LLU enabled exchanges

Look forward to your replies

Renoir

In reply to a post by Renoir:

Hi guys,

I am currently on the talktalk LLU up to 8meg service and was hoping people could confirm whether or not the following info is correct:

1) Talktalk LLU means they have put their own DSLAM in the exchange and have their own cables going from the exchange to their premises therefore bypassing BTs backhaul network

Yes, although they are MSAN (Multi Service Access Node). DSLAMS only provide either voice or data and require two pieces of equipment to provide ADSL and voice services. MSAN's provide all services through one piece of equipment within the exchange and this is the same quipment BT OR are installing for their 21CN network.

In reply to a post by Renoir:

2) All of talktalks DSLAMs are ADSL2+ up to 24mb capable

Yes - Huawei MSANs. Samknows can tell you if your exchange has been unbundled.

In reply to a post by Renoir:

3) These DSLAMs are however also capable of ADSL1 which is the "mode" in which they work if you are on their regular up to 8mb service

Nope, the MSANs are set to auto on the connection mode. It will connect at the best mode for your line. The downstream rate limit is enforced by which ADSL profile you are placed on. you could be on an 8mbit profile connected on ADSL2+

In reply to a post by Renoir:

4) Signing up to their speed boost option merely causes the DSLAM to work in it's ADSL2+ "mode" instead of ADSL1

As above. The speed boost will allow you to move off a capped 8mbit limit to a 24mbit profile. This isn't a change of ADSL Mode.

In reply to a post by Renoir:

5) Talktalk say your line needs to be capable of 8mb if it is to be eligible for the speedboost simply because it implies you are using their LLU equipment rather than BTs because talktalk don't offer a up to 8mb service on non LLU enabled exchanges

Correct. The BT DSLAMS are only capable of ADSL1 (up to 8mbit). To benefit from speeds greater than 8mbit you would need to be on LLU and already at or close to 8mbit. If you can post your current line stats we can advise what you could potentially get.

In reply to a post by Renoir:
Hi guys,

I am currently on the talktalk LLU up to 8meg service and was hoping people could confirm whether or not the following info is correct:

1) Talktalk LLU means they have put their own DSLAM in the exchange and have their own cables going from the exchange to their premises therefore bypassing BTs backhaul network



Yes, although they are MSAN (Multi Service Access Node). DSLAMS only provide either voice or data and require two pieces of equipment to provide ADSL and voice services. MSAN's provide all services through one piece of equipment within the exchange and this is the same quipment BT OR are installing for their 21CN network.

Righty oh

In reply to a post by Renoir:
2) All of talktalks DSLAMs are ADSL2+ up to 24mb capable



Yes - Huawei MSANs. Samknows can tell you if your exchange has been unbundled.

I was moved to LLU in Feb 07

In reply to a post by Renoir:
3) These DSLAMs are however also capable of ADSL1 which is the "mode" in which they work if you are on their regular up to 8mb service



Nope, the MSANs are set to auto on the connection mode. It will connect at the best mode for your line. The downstream rate limit is enforced by which ADSL profile you are placed on. you could be on an 8mbit profile connected on ADSL2+

Does what version of ADSL my router supports affect which mode it's in. For example if I had a ADSL1 only router would the MSAN automatically switch to ADSL1 mode with an 8mbit profile?

In reply to a post by Renoir:
4) Signing up to their speed boost option merely causes the DSLAM to work in it's ADSL2+ "mode" instead of ADSL1



As above. The speed boost will allow you to move off a capped 8mbit limit to a 24mbit profile. This isn't a change of ADSL Mode.

As per previous question would it be a change of ADSL mode if I was changing from an ADSL1 router to an ADSL2+ router at the same time as ordering the speed boost?

In reply to a post by Renoir:
5) Talktalk say your line needs to be capable of 8mb if it is to be eligible for the speedboost simply because it implies you are using their LLU equipment rather than BTs because talktalk don't offer a up to 8mb service on non LLU enabled exchanges



Correct. The BT DSLAMS are only capable of ADSL1 (up to 8mbit). To benefit from speeds greater than 8mbit you would need to be on LLU and already at or close to 8mbit. If you can post your current line stats we can advise what you could potentially get.

As above I am on LLU and my line stats are the following:

My Netgear DG834G router shows different connection speeds on the "router status" page and on the "show statistics" page so have included both. What's the difference between these 2 sets of numbers?

Statistics Downstream Upstream
Router Status Speed 5637 793
Show Statistics Speed 6785 890
Noise Margin 11.8 dB 11.8 dB
Line Attenuation 38.5 dB 19.0 dB
Thinkbroadband Test 5190.93 729.18

Renoir

You could get your self a free speed boost by getting TalkTalk to change the ridiculously high 12db noise margin to a much more sensible 6db margin .

Try requesting this on the TalkTalk members forum

In reply to a post by Renoir:

Does what version of ADSL my router supports affect which mode it's in. For example if I had a ADSL1 only router would the MSAN automatically switch to ADSL1 mode with an 8mbit profile?
...
As per previous question would it be a change of ADSL mode if I was changing from an ADSL1 router to an ADSL2+ router at the same time as ordering the speed boost?

The MSAN negotiates connections in a backwards compatible manner, so yes, if you had a router that did not support ADSL2 or ADSL2+, you'd get an ADSL1 connection. The profile is a separate matter - e.g. you can still be on a 24mbit profile when using ADSL1 (the upload speed will be higher than on a 8mbit profile). Your DG834G does support ADSL2+ though, in case you weren't aware (IIRC, the official Netgear software doesn't show anywhere in the router config pages whether the connection is ADSL1, ADSL2 or ADSL2+).

If you are considering the speed boost, from your line stats I would recommend that you don't bother and save £4 per month . Your line wouldn't really be able to make use of it. If you ask TT to tweak your profile (to lower your SNRM) you will be able to get a faster sync speed, but you're not likely to get much over 8Mb if at all. I mean, my stats are similar to yours and I can get 9.5Mb on a good day, but IMO it's not worth paying £4 per month for an extra 1.5Mb.

In reply to a post by woweebert:

You could get your self a free speed boost by getting TalkTalk to change the ridiculously high 12db noise margin to a much more sensible 6db margin .

Try requesting this on the TalkTalk members forum

Agreed, but it's only ridiculous if there is less than 6db swing on the noise margin during normal conditions - depends on the line quality and interference, obviously. A 6db profile is unfortunately only "sensible" (i.e. stable) for a minority of lines .

In reply to a post by Renoir:

Does what version of ADSL my router supports affect which mode it's in. For example if I had a ADSL1 only router would the MSAN automatically switch to ADSL1 mode with an 8mbit profile?

Yes, the MSAN supports ADSL2+, ADSL2, T1.413, g.dmt (ADSL1) but not g.lite or Annex M ADSL2+. RE-ADSL2 is available but not supported because of crosstalk in the cable bundles.

The profile is set by TT separately, they have a variety for difficult situations.

On point (1) it should be pointed out that TalkTalk does not have its own cables to the premises, they rent the cable from Openreach, who look after the copper local loop for all communications providers.

Thanks very much for the replies guys!

In reply to a post by Futaura:

The profile is a separate matter - e.g. you can still be on a 24mbit profile when using ADSL1 (the upload speed will be higher than on a 8mbit profile). Your DG834G does support ADSL2+ though, in case you weren't aware (IIRC, the official Netgear software doesn't show anywhere in the router config pages whether the connection is ADSL1, ADSL2 or ADSL2+).

I am aware it supports ADSL2+ but you are correct in that the netgear software does not say which connection the router is using. Being on a 24mbit profile with ADSL1 is not something I knew was possible. Is the the higher upload speed the only benefit to that?

In reply to a post by Futaura:

If you are considering the speed boost, from your line stats I would recommend that you don't bother and save £4 per month smile. Your line wouldn't really be able to make use of it. If you ask TT to tweak your profile (to lower your SNRM) you will be able to get a faster sync speed, but you're not likely to get much over 8Mb if at all.

Do you mean I'd be unlikely to get much over 8mb with a combination of the speed boost and a lower SNRM? I ask because you can't mean I'd be able to get over 8mb just with a tweaked SNRM because it'd still be capped at 8mb wouldn't it?

In reply to a post by Futaura:

Agreed, but it's only ridiculous if there is less than 6db swing on the noise margin during normal conditions - depends on the line quality and interference, obviously. A 6db profile is unfortunately only "sensible" (i.e. stable) for a minority of lines frown.

So line tweaking could cause drop outs if the SNRM is set too low?

In reply to a post by MrSaffron:

On point (1) it should be pointed out that TalkTalk does not have its own cables to the premises, they rent the cable from Openreach, who look after the copper local loop for all communications providers.

Just to be clear I said the cables from the exchange to "their" premises were their own not to my premises hence my mentioning of bypassing BT's backhaul network. Is that not correct?

Renoir

In reply to a post by Renoir:

In reply to a post by Futaura:

The profile is a separate matter - e.g. you can still be on a 24mbit profile when using ADSL1 (the upload speed will be higher than on a 8mbit profile). Your DG834G does support ADSL2+ though, in case you weren't aware (IIRC, the official Netgear software doesn't show anywhere in the router config pages whether the connection is ADSL1, ADSL2 or ADSL2+).

I am aware it supports ADSL2+ but you are correct in that the netgear software does not say which connection the router is using. Being on a 24mbit profile with ADSL1 is not something I knew was possible. Is the the higher upload speed the only benefit to that?

Actually, they may have changed the 8mbit profiles to have the same upload as the 24mbit profiles, which would make the profiles pretty much the same apart from the download sync speed being capped on the 8mbit profile. Not 100% sure on that though. When I changed to a 24mbit profile some time ago, I know my old 8mbit profile was limited to 443kbps or so upload.

In reply to a post by Renoir:

In reply to a post by Futaura:

If you are considering the speed boost, from your line stats I would recommend that you don't bother and save £4 per month smile. Your line wouldn't really be able to make use of it. If you ask TT to tweak your profile (to lower your SNRM) you will be able to get a faster sync speed, but you're not likely to get much over 8Mb if at all.

Do you mean I'd be unlikely to get much over 8mb with a combination of the speed boost and a lower SNRM? I ask because you can't mean I'd be able to get over 8mb just with a tweaked SNRM because it'd still be capped at 8mb wouldn't it?

Yes. Without the speed boost, your throughput is capped to 8mb if your sync speed is higher. It's worth trying a 24mbit profile with lower SNRM just to see what your line is capable of. What I meant was that if it turns out your line maxes out at 9Mb sync speed for example, is it worth paying £4 per month for that extra 1Mb? I'm in that position, so I'm definitely not going to pay for the speed boost .

In reply to a post by Renoir:

In reply to a post by Futaura:

Agreed, but it's only ridiculous if there is less than 6db swing on the noise margin during normal conditions - depends on the line quality and interference, obviously. A 6db profile is unfortunately only "sensible" (i.e. stable) for a minority of lines frown.

So line tweaking could cause drop outs if the SNRM is set too low?

Yes. Depends how stable your line is and how much your SNR varies during a 24 hour period (it's by no means unusual for SNR to drop after dark, for example). But, like I say it's worth trying more aggresive profiles. Also, in theory, if your line is being monitoring by dynamic line management, your profiles will automatically change over time. AFAIK, DLM is not active on all lines yet, but is being rolled out nationally.