Sudden drop in speed coinciding with new WAN IP

[#1]

The slow speeds prior to the 25th can be disregarded - they relate to a problem that was eventually resolved. As can be seen from the graph, I was blessed with about 6 weeks of speeds that I'm paying for! But sadly, no more: the speed has once again taken a turn for the worst.

Some observations;

1. When the speed was OK, the WAN IP was 80.189.12.x. At the moment of drop in speed, it went to 31.185.206.x.

2. This occurred between 07/11/2016 03:45 and 07/11/2016 04:00. (Yes, since the previous speed disaster, I now measure and log the speed every 15 minutes.) And no, I wasn't making changes at that time in the morning.

3. The download sync speed before and after is about 62700 kbps. (Right now it is 62700.)

4. A router reboot doesn't fix it.

5. I believe I am now on a new gateway: pcn-ir01. I was not on a new gateway when I had the old problems, so I suspect that the new IP coincides with my migration to Plusnet's <irony>shiny new network</irony>.

With my previous problem, I had 2 months of slow speeds - I am sincerely hoping that I don't have another 2 months of sub-MGALS speeds!

Any ideas?

[#2]

I've just tested your line and it's identified a profile mismatch on the DLM side of things so I've reported a fault and will get this reported through to our suppliers for further investigation.

Sorry for the issues but we'll get this sorted asap for you.

[#3]

Chris, thanks very much indeed for your help on this. 

[#4]

For some reason one of the profiles on our suppliers side is incorrect, and for some odd reason when I test your line the downstream sync shows as 0.

Description	GEA service test completed and no fault found but unable to check for customer equipment connected to modem.
Main Fault Location	OK
Sync Status	In Sync
Downstream Speed	0.0 Mbps
Upstream Speed	20.0 Mbps

Can you run a BT Speedtest for me, ensuring you do the further diagnostics test after the first one completes. This stores the results on the supplier system.

[#5]

The 0.0 Mbps problem is actually something that came to light when I had my speed problem a few weeks back. It's something that's specific to the Asus DSL AC68U, I think. If I put the One Hub back, I'm sure you'll see the downstream speed. 

When I get in tonight, I'll run the full Speedtest and post the results. Would you prefer me to do it on the Asus or swap the One Hub back in for the test?

[#6]

It shouldn't matter really, I'm just looking to be able to push this through with a low result.

[#7]

Hi Chris, OK, the test is done and the results are uploaded.

All the best

[#8]

How did you get that graph.

Is it automated or do you input the data manually?

Thanks in advance.

[#9]

The data comes from a bash speedtest script that I've customised a little (but it's based on the many that you find if you google). It runs on Raspberry Pi. The output is a CSV to which it appends and then uploads it to Dropbox every 15 minutes (so I can tell when the speed takes a sudden hit). I then import into Excel 2016 and add a bar graph. 

I did consider a SamKnows box but AFAIK that doesn't measure it as often.