DLM profiles + questions

Hi

Is this article correct still http://www.thinkbroadband.com/news/5929-reminder-abo... or has the way it works changed?

I'm told my profile is "0.128M-80M Downstream, Retransmission Low - 0.128M-20M Upstream, Error Protection Off" and syncing at 61mbps.

Can retransmission be set to off?

What is involved when BT engineer does a DLM profile reset.... I'm guessing its a 5 minute job once at the exchange?

Can G.INP be disabled on lines? Reason i ask is i used to sync at 80mbps until the day G.INP was added to my line (I had ECI modem on huawei cab...but now i have huawei modem and even changed ISP and my speed has never improved)

Thanks.

As far as I know it's still the same.

I'm not sure if retransmission can be turned off.

I believe for a DLM reset the engineer makes a phone call and the team he speaks to can reset the DLM software that runs the kit in the cabinet.

It may well be the case that more customers have since been connected on your cabinet and the crosstalk has reduced your connection speed. What is the maximum attainable rate for your line?

I don't think G.INP would be able to be removed for individual connections but I could be wrong.

All you have to do is use an ECI modem. You can buy these for about a quid on Ebay as they don't support G.INP.

Alternatively, if you want to keep your Huawei, just apply the original hacked firmware which doesn't support G.INP either.

Edited by deleted (Wed 27-Jan-16 08:38:50)

In reply to a post by Leki:

Is this article correct still http://www.thinkbroadband.com/news/5929-reminder-abo... or has the way it works changed?

No. That article dates back to before BT rolled out G.INP support in any form.

Nowadays, most lines from a Huawei cabinet will have downstream set to "retransmission low" and upstream set to "error protection off".

What happens when DLM is reset is somewhat ambiguous. Some evidence suggests the initial setting turns error protection off in both directions, as used to be the case. However, we have been told that a DLM reset should now set downstream "interleaving low" as the initial option (upstream off), before changing downstream to "retransmission low" when it recognises the modem as capable.

It isn't clear whether that behaviour for a DLM reset should only apply to Huawei cabinets.

More information available here:
http://www.kitz.co.uk/adsl/retransmission.htm

In reply to a post by Leki:

I'm told my profile is "0.128M-80M Downstream, Retransmission Low - 0.128M-20M Upstream, Error Protection Off" and syncing at 61mbps.

Can retransmission be set to off?

Yes. It is off in the upstream direction, and DLM can choose to turn it off in the downstream direction.

In reply to a post by Leki:

What is involved when BT engineer does a DLM profile reset.... I'm guessing its a 5 minute job once at the exchange?

No visit is required. DLM resets are triggered from an Openreach operations centre (somewhere in Bristol?), upon request from an engineer. Engineers aren't free to request a DLM reset willy-nilly; they need to be able to justify it - for example, by fixing a physical fault with the line.

In reply to a post by Leki:

Can G.INP be disabled on lines? Reason i ask is i used to sync at 80mbps until the day G.INP was added to my line (I had ECI modem on huawei cab...but now i have huawei modem and even changed ISP and my speed has never improved)

No it cannot be disabled - DLM cannot be told to never use it as an option.

Is your Huawei unlocked? If so, what firmware version is it using? It needs to be an updated version in order to support G.INP.

If it is unlocked, can you provide a copy of the line stats?

Re WWWombat's reply, the required unlocked version is V100R001C01B030SP08

In reply to a post by RobertoS:

Re WWWombat's reply, the required unlocked version is V100R001C01B030SP08

That firmware has G.INP enabled. If the OP wants to prevent G.INP is B030SP06 the required version?

The OP is asking whether G.INP can be disabled, in the apparent belief that G.INP is causing a reduction in their line speeds.

They might be mistaken in that belief. The problem might be caused by a modem that fails to make proper use of G.INP instead - and in my experience, this is much more likely. Even with Huawei modems.

Finding out which case is true, before advocating how to fix it, is by far the best course of action here.

If the problem is caused by old firmware on the Huawei, then the OP is likely to achieve a better result, by a large margin, by upgrading the modem and leaving G.INP active.

Standard trouble-shooting approach: Make sure you are in possession of as many facts as you can get hold of.

The op asked this

In reply to a post by Leki:

Can retransmission be set to off?

The answer is, yes it can - either by using an ECI modem (or any other) that doesn't support G.INP or by downgrading the HG612 firmware to one that doesn't.

I agree that using a modem that fails to support G.INP has the effect of forcing G.INP to remain unused. I'm not sure that is quite the same as setting it to off. But that's a question of language, and I'm not so worried about that.

The real problem is that by answering that, alone, so bluntly, does the OP a disservice. You don't help him understand context, you don't help him identify the real cause of his problem, and you don't help him attain the best result for his line.

Continuing bluntly, it is a lazy answer.

I'm sure you know better than the OP what the OP wants.