In reply to a post by RobertoS:

In reply to a post by tommy45:

As for your speed, that is currently being restricted by the current Bras IP profile which is set by Bt's woeful DLM

Slow down Tommy .

The Bras IP Profile is set by the connection speed, not the other way round. Connection speed (15285kbps) x 0.882 = 13.48Mbps which is the IP Profile displayed.

Nothing at all wrong there. The reason for the low connection speed is what we need to look for. Sort that out and the IP Profile will track it.

The diagnostic tests you suggest might help.

Edit - IIRC the 828kbps upstream might be the maximum on BTW interleaved.

And what controls the sync rate, DLM?

And yes i know that the bras IP profile is set based on what the sync is , and i didn't say differently But it still can restrict throughput , should that IP profile get stuck or fail to update correctly(which is a known issue) that it's self can be a reason for low throughput on a high sync, not that i'm saying it is the case here,(just to be clear)

Edited by tommy45 (Thu 22-May-14 01:48:41)

In reply to a post by tommy45:

And what controls the sync rate, DLM?

And yes i know that the bras IP profile is set based on what the sync is , and i didn't say differently

You did, you mixed up the 2:

In reply to a post by tommy45:

As for your speed, that is currently being restricted by the current Bras IP profile which is set by Bt's woeful DLM

which Roberto was clarifying.

Yes, the DLM controls the sync rate by responding to the line conditions which appear to be imperfect.

If DLM sets the sync speed then as a result of that DLM is responsible for the bras profile as well, wether directly or not, How is that mixing the 2 up?,

I have a friend who lives literally 5 metres from the exchange. however, he only gets about 12.5meg. Reason? Instead of turning left as it leaves the exchange, his line goes right, into town, out of town about 1 mile, does a uturn, goes through a huge estate and then finally, after travelling another .75 miles, arrives at his house!

Craziness!!!

For a pure phone service it was probably the easiest and cheapest way to do it as that is probably where the ducts were. They wouldn't have known at the time that line length would become critical to services that didn't exist then.

haha yep very true. He isn't that bothered as he doesn't use the Internet very much.

In normal circumstances the DLM does not set the sync speed. It sets various stability parameters. The same parameters are set by LLU ISPs whether or not they permanently run a DLM or just for an initial period. Similarly in the case of FTTC, the Openreach DLM sets the parameters.

In cases of severe instability the BT Wholesale or Openreach DLM can apply banding. That does restrict the sync speed, but does not set it.

The sync speed is negotiated by the modems at each end, taking into consideration those parameters and more importantly the actual line conditions at the time of connection. That's why on lines that are not capable of running at the maximum speed for the product using them that the sync varies each time a connection is made. The parameters set by the DLM do not change, but the line conditions do.

That's the RAS in BRAS.

You have a rough idea of what you are talking about, but your initial statement about the DLM restricting the speed was misinformation of the kind that creates broadband myths.

Edit - Nor is there much wrong with the current BT Wholesale and Openreach DLMs. Far from "woeful".

Edited by RobertoS (Thu 22-May-14 10:51:30)

In reply to a post by RobertoS:

In normal circumstances the DLM does not set the sync speed. It sets various stability parameters. The same parameters are set by LLU ISPs whether or not they permanently run a DLM or just for an initial period.
Similarly in the case of FTTC, the Openreach DLM sets the parameters In cases of severe instability the BT Wholesale or Openreach DLM can apply banding. That does restrict the sync speed, but does not set it..

What about LLU ISP's that don't run DLM at all, where DLM doesnt exist, ?
Which often results in customers getting a higher sync rates compared to where LLU DLM is used,It can cap the headline speeds too,

In reply to a post by RobertoS:

The sync speed is negotiated by the modems at each end, taking into consideration those parameters and more importantly the actual line conditions at the time of connection. That's why on lines that are not capable of running at the maximum speed for the product using them that the sync varies each time a connection is made. The parameters set by the DLM do not change, but the line conditions do.

That's the RAS in BRAS.
You have a rough idea of what you are talking about, but your initial statement about the DLM restricting the speed was misinformation of the kind that creates broadband myths.

For BTW systems, DLM works differently ,
But the IP profile can restrict throughput, if it fails to detect or get updated as to what the current sync rate is, should that be higher than it previously was, And DLM can & does ramp up the target noise margins, that in turn does lower the sync rate, So if that isn't DLM controlling the sync rate i don't know what is,

In reply to a post by RobertoS:

Edit - Nor is there much wrong with the current BT Wholesale and Openreach DLMs. Far from "woeful".

As for the BTW 21cn /FTTC Openreach DLM not being "woeful" well thats a matter of opinion maybe we should have a poll to see how many are for DLM or against it?

Edited by tommy45 (Thu 22-May-14 13:34:45)

In reply to a post by WelshWArrior:

Instead of turning left as it leaves the exchange, his line goes right, into town, out of town about 1 mile, does a uturn, goes through a huge estate and then finally, after travelling another .75 miles, arrives at his house!

Then that detour will be reflected in his attenuation and he will have a much higher attn. then the 10dB of the OP.

So his circumstances are not relevant to the OP's issue.

I think we can now leave the OP and anyone who comes across the thread in the future to make there own mind up . There's too much wrong or out of date in that post for me to have the will to go over it all again, as most of it has been covered in earlier posts.