I think estimating a sync speed rate from a speedtest isnt the right way to go surely. For thsoe with locked modems the best way is the BTw tester and getting the IP profile (and hoping that profile is up to date not stuck).

In reply to a post by robertcrowther:

Not sure if this is the speedtester you are referring to: http://diagnostics.bt.com/login/?workflow=Speed

No, OP isn't! That's a BT Retail speedtester that only gives sync speed if you are a BTr BB cust. Think it works by interrogating the BT Home Hub.

It will work on other BTw connections (by answering another Q) but it omits the sync speed.

In reply to a post by MrSaffron:

If sync is 80000 Kbps, then IP Profile is 96.2% of this i.e. 76960

It's 96.79, not 96.2 - maximum IP profile is 77.43 Mbps.

Edited by kasg (Sat 05-Oct-13 11:53:50)

It uses the BT Agent to get the sync speed from the modem.

In reply to a post by ryant704:

the BT Agent

Who is he? Any modem?

In reply to a post by ryant704:

It uses the BT Agent to get the sync speed from the modem.

does it get it from the modem? or does it ask the hub ask the modem?
(I think the latter, since it only seems to work with a hub, not just a standard modem and a third party router)
- either way, its a possible way, to get some stats from the locked modems...

In reply to a post by XRaySpeX:

In reply to a post by robertcrowther:

Not sure if this is the speedtester you are referring to: http://diagnostics.bt.com/login/?workflow=Speed

No, OP isn't! That's a BT Retail speedtester that only gives sync speed if you are a BTr BB cust. Think it works by interrogating the BT Home Hub.

That's unlikely - because the sync speed is not passed back to the Home Hub.

The PPP intermediate agent in the DSLAM in the cabinet inserts various fields, including downstream and upstream sync speeds, into the PADI sent to the BRAS. This data is stripped in the subscriber direction, so would not be passed through to the Home Hub. BT SIN 498 paragraph 2.1.7 refers.

BT Agent is part of the software within a modem supplied by Openreach.

From my memory, I believe each ISP has their own agent and is installed upon first sync

http://i41.tinypic.com/11r3zoj.jpg

@David, that is the decision from BT Retail not to display any stats. Originally the sync speed was displayed then they removed it, probably due to high complaints? idk. Ed said to me who is from the ELC team no other ISPSs offer any line stats or don't show the sync speed (which is wrong, there are various ISPs who show the sync speed on VDSL2.)..

Edited by deleted (Sun 06-Oct-13 01:01:09)

In reply to a post by David_W:

That's unlikely - because the sync speed is not passed back to the Home Hub.

Ah, I was talking about ADSL, since the OP postulated an ADSL speedtester ported forward to FTTC.

Do we actually know that the BT Retail speedtester, that I was commenting on, works on FTTC and does report sync speeds for BTr custs?

In reply to a post by XRaySpeX:

In reply to a post by David_W:

That's unlikely - because the sync speed is not passed back to the Home Hub.

Ah, I was talking about ADSL, since the OP postulated an ADSL speedtester ported forward to FTTC.

Do we actually know that the BT Retail speedtester, that I was commenting on, works on FTTC and does report sync speeds for BTr custs?

I'm with you now. I based my answer on the BT Openreach documentation and packet traces I've examined of what happens with FTTC on my line.

On FTTC, the subscriber end doesn't get the synchronisation speed passed to it by the DSLAM in the cabinet (a shame, otherwise I could add it to my logs), and the BT Openreach modems are normally locked in such a way to preclude the subscriber from reading sync speed and other technical data out of the modem. There are now known ways to access technical data on both types of modem, though I believe there's still some issues with gaining access to the newest version of the ECI modem.


If the BT Retail speed tester or the Home Hub knows FTTC synchronisation speeds, this data is most likely coming from the BRAS, or is coming from periodic monitoring reports about end user circuits passed to BT Retail by BT Openreach via BT Wholesale (in this case, BT Wholesale are BT Openreach's customer - BT Retail are BT Wholesale's customer).

Zen make a synchronisation speed history available via their customer portal. Other ISPs often have similar 'self help' solutions to get hold of data about your line.


On BT Retail ADSL, the DSL modem is in the Home Hub, which therefore has access to the key line parameters.