I am on an Unlimited FTTC product from an ISP that I'd rather not name.
My exchange isn't 21CN.
During the evening, I get a solid 75Mbit/s or over on every download speed test I've tried.
Here's an example wholesale speed test result from just now:
Download speed achieved during the test was - 77.77 Mbps
For your connection, the acceptable range of speeds is 40 Mbps-77.42 Mbps .
Additional Information: IP Profile for your line is - 77.42 Mbps
Upload speed is about 13Mbit/sec and does not slow during the day -- it is pretty constant (IP Profile is 20Mbps according to the BT wholesale test)
Here's the problem:
During the day, from around 10am to 5pm, speeds plummet, down to 2 or 3Mbit/sec at times, though today it has been more like 30Mbit/sec.
I don't care about these slowdowns really. What I do care about is what seems to packet loss or at least a latency increase at the same time as things slow down. When using ssh my connection is laggy. VoIP is usable but only just, with nasty juddery audio. Using MTR I see packet loss on every single hop, right after the router.
The TBB BQM typically looks like this:
My ISP (who are a BT wholesale customer) says there is no problem on their network and there are no issues on my line. They are blaming my equipment.
Is my problem likely to be congestion somewhere? I'd love some expert opinions on this.
It is highly unlikely to be electrical interference - we are in a residential neighbourhood with no industrial anything anywhere near, and not anywhere near the path the phone line takes to the cabinet.
Besides, the upload is unaffected, and although I appreciate it uses different frequencies to the download, they aren't that different, are they? I mean it would have to be something pumping out noise at a very specific frequency to affect only download and not upload?