BT IP Profile too low?

I'm seeing slower throughput on my FTTC line than I expect.

My sync speed is 68.31 Mbps, and is stable, but I only get throughput speeds of c.60 Mbps. When I run the BT Wholesales Speedtest, it reports my IP profile as 63.1 Mbps, and I think that's the issue: shouldn't this profile be closer to 66 Mbps (96.8% of sync speed)?

Is there a way for my ISP to request BT reset the IP profile on its system? The ISP has already requested a DLM reset, but this hasn't improved it.

Your line has probably been set to retransmission high; there is discussion about a line with similar problems here.

If you search there are ways to reset the retransmission parameter which involve deliberately capping the download speed until the retransmission value changes to low than gradually raising the cap but it is a bit of a palaver unless you really need the extra speed.

Thanks, GonePostal.

Do you know how the 'retransmissions high' would be reported in the BTw linetest stats? I've got those stats from my ISP, but don't know what I'm looking for!

(Also, as an aside, any ideas what G.INP (in the other post you linked to) stands for?)

In reply to a post by garywood84:

(Also, as an aside, any ideas what G.INP (in the other post you linked to) stands for?)

Lots of info here:
G.INP Retransmission

There will be lots of search engines that can access better technical knowledge than I have.

Edit: Typing while flilot was posting.

Edited by GonePostal (Mon 03-Aug-20 00:02:51)

Thanks flilot.

So it turns out that "Retransmission" is set to "Low" and error protection is "Off" - so I'm still not sure why my IP profile is only 92% of the sync speed...

Thanks, GonePostal - just none that know what G.IMP stands for (as opposed to what it means)! I assume it's an acronym, and I'd like to know what of...

In reply to a post by garywood84:

Thanks, GonePostal - just none that know what G.IMP stands for (as opposed to what it means)! I assume it's an acronym, and I'd like to know what of...

The INP part stands for Impulse Noise Protection.
The G. part just means its part of the ITU specifications, within the G series: Transmission systems and media, digital systems and networks
The actual ITU specification is G.998.4
G.INP is just a friendly name thats easier to remember than the specification number.

In reply to a post by garywood84:

Thanks flilot.

So it turns out that "Retransmission" is set to "Low" and error protection is "Off" - so I'm still not sure why my IP profile is only 92% of the sync speed...

IT's a BUG in BTW system requires a manual intervention to put it right if you are with BT RETAIL , GOOD LUCK WITH THAT
No offence but you get what you pay for when it comes to CS with isp's

Thanks, tommy45.

Do you have any further information about what this bug is or what's necessary to fix it, so I can give me ISP specific instructions?

In fairness to the ISP, they've actually been very helpful so far, and I'm talking to tier 2 support now.

As the person who was the OP in the thread that GonePostal linked to, I will be very interested to see how you get on. A quick caluculation suggests your IP profile is set at 92.3% and mine at 92.2%, so suspect a similar mechanism has come into play for both of us.

I only spotted the issue on mine as I am obsessive enough to maintain a Speedtest results spreadsheet and noticed my TBB download speed had dropped from ~73.7 to ~70.5 Mbps.

In reply to a post by garywood84:

Thanks flilot.

So it turns out that "Retransmission" is set to "Low" and error protection is "Off" - so I'm still not sure why my IP profile is only 92% of the sync speed...

Where did you get that info?

The line profile reported on a GEA test (an ISP test) reports a 13 day old profile.
So if this started in the last 13 days it wouldn't yet be reflected in a GEA test.

On a Broadcom (modem) chipset you can see if a line is ReTx Low or High via looking at the detailed statistics.

Bearer 0, INPRein = 0 is ReTx Low
Bearer 0, INPRein = 1 is ReTx High

Then there's what tommy45 reports, where the IP profile is calculated incorrectly by BT Wholesale.
This appears to need an entire circuit rebuild and is no guarantee it won't happen again in the future.

Edited by j0hn83 (Mon 03-Aug-20 14:10:44)