Sync rate - Minimum handback threshold?

[#1]

Hi There,

I'm getting in touch because my FTTC sync rate has now dropped to 49mbps  and my upload to 17.5mb since the 28th of march according to the router logs.  It has been gradually dropping over the last year I suspect due to cross talk but this is a new low.

Can you please check the line and advise if there is a fault?  What is the minimum handback threshold for this line?

When I began the journey of FTTC I was on a solid 67-65mb down/ 20mb up.

Your help is appreciated.

[#2]

Thanks for getting in touch.

I'm sorry to hear that your speeds have dropped.

We've tested your line and whilst we can see that the speeds have dropped our tests aren't showing any exact cause for this.

In terms of the handback threshold for your line this is 45.8mbps so you are above this at this moment in time.

I'd recommend raising a fault here so we can investigate further and posting back once you've done so.

This will allow us to get your issue picked up straight away and escalated to the relevant team

[#3]

Hi Matthew,

That link takes me to a bobby basic KB troubleshooter asking me to test with the master socket.  It's not an internal wiring issue though I appreciate you need to run some people though that.

I'm not ruling out that is the constant march of cross talk however there needs to be a limit to the gradual decline you put up with.

BT wholesale report handback threshold of my line at 51.5mb for a clean line.  Why are you quoting the impacted line threshold?  What dictates an impacted line over a clean line?

The drop of another 5mbit occurred at 1am in the morning according to the router log with a resync.

Below is an extract of the wan log from the router -

01:33:35, 28 Mar.	( 137.560000) PPPoE is up -​ Down Rate=49674Kbps, Up Rate=17484Kbps; SNR Margin Down=6.1dB, Up=6.1dB
01:33:35, 28 Mar.	( 137.550000) CHAP authentication successful
01:33:34, 28 Mar.	( 137.400000) CHAP Receive Challenge
01:33:34, 28 Mar.	( 137.400000) Starting CHAP authentication with peer
01:33:34, 28 Mar.	( 137.390000) PPP LCP Receive Configuration ACK
01:33:34, 28 Mar.	( 137.390000) PPP LCP Send Configuration Request
01:33:34, 28 Mar.	( 137.390000) PPP LCP Receive Configuration Reject
01:33:34, 28 Mar.	( 137.390000) PPP LCP Send Configuration ACK
01:33:34, 28 Mar.	( 137.380000) PPP LCP Receive Configuration Request
01:33:34, 28 Mar.	( 137.380000) PPP LCP Send Configuration Request
01:32:45, 28 Mar.	( 88.190000) PTM over DSL is up
01:31:57, 28 Mar.	( 40.300000) WAN Auto-​sensing running.
01:30:45, 28 Mar.	(2224564.820000) PPP LCP Send Termination Request [User request]
07:35:54, 02 Mar.	( 133.370000) WAN operating mode is VDSL
07:35:54, 02 Mar.	( 133.370000) Last WAN operating mode was VDSL
07:35:53, 02 Mar.	( 132.270000) PPP IPCP Receive Configuration ACK
07:35:53, 02 Mar.	( 132.260000) PPP IPCP Send Configuration Request
07:35:53, 02 Mar.	( 132.250000) PPP IPCP Receive Configuration NAK
07:35:53, 02 Mar.	( 132.250000) PPP IPCP Send Configuration ACK
07:35:53, 02 Mar.	( 132.250000) PPP IPCP Receive Configuration Request
07:35:53, 02 Mar.	( 132.250000) PPP IPCP Send Configuration Request
07:35:52, 02 Mar.	( 131.310000) PPPoE is up -​ Down Rate=55282Kbps, Up Rate=20000Kbps; SNR Margin Down=6.0dB, Up=6.1dB

The 1.30am resync and speed drop coincides with this in the router log a firmware update to the router -

01:31:53, 28 Mar.	( 35.510000) System up, firmware version: 4.7.5.1.83.8.263
01:31:38, 28 Mar.	( 20.810000) System start TR069
07:34:09, 02 Mar.	( 28.300000) System up, firmware version: 4.7.5.1.83.8.237.2.2

Is it a concidence that a firmware update to the router just happens to coincide with reduced sync rates?

[#4]

Yes and No.

Typically on a synched line, the SNR will reduce overnight. The firmware upgrade caused a resynch in the early hours. This would have caused the line to synch at a lower speed to achieve the target noise margin of 6db.

Try forcing .a resynch at around the 7:30 time and see if you get the speed back.

[#5]

Hi @Aurhinius,

I'm sorry to hear that you've experienced this issue. I've tested your line again this morning and you're still receiving a lower sync speed than we would expect. Whilst I do appreciate that nothing may seem to have changed internally, we would still ask that you go through our online troubleshooting guides, so that we can help to narrow down where the fault lies. Our online troubleshooting guide can be found here and another guide detailing how you can set your router up within the test socket of the property can be found here, which I would also highly recommend going through.

If these guides fail to show any improvement to your speed then I have raised a ticket response on your account regarding the next steps we'd need to take to progress the investigation of this matter further. For reference, this ticket can be found here.

Please let us know how you get on with all this and if you respond to the ticket then please also let us know on here so that we can pick this back up for further review as soon as possible.

[#6]

Hi there,  I have replied to the question. I think this needs an engineer to come and probably move the pair or re-terminate in the cabinet in the hopes that improves things.  Whatever they need to do.

I imagine it's highly unlikely they will run new copper.

[#7]

Thanks for getting back to us.

We'll get the open fault updated shortly with confirmation