topic Re: Traffic shaping in Broadband

Traffic shaping

Cliff_g — Thu, 03 Oct 2024 11:54:32 GMT

I'm having an odd speed limit (of 500 kbps) downloading emails (from my own domain on a 3rd party UK server) on my FTTC 35+ Mbps connection, along with a couple of other instances of data from that same server. Began about a month ago, prior to that the download speeds were line speed.

Together we've so far been unable to track down the reason but the ISP concerned has asked me to check whether Plusnet or BT/Openreach perform any traffic shaping. Can anyone advise, please? I am able to download http/s data at fuill line speed.

The tracert is as follows:

1    52 ms     1 ms     2 ms dsldevice.lan [192.168.1.254]
2    23 ms    22 ms    23 ms 250.core.plus.net [195.166.130.250]
3    65 ms    22 ms    50 ms 84.93.253.87
4    24 ms    22 ms    23 ms 195.99.125.144
5     *       28 ms    29 ms peer8-et3-0-4.telehouse.ukcore.bt.net [109.159.252.174]
6     *        *        *     Request timed out.
7     *        *        *     Request timed out.
8    31 ms    30 ms    30 ms 80.169.252.66
9    30 ms    29 ms    49 ms (ISP's server) [xx.xxx.xx.xx]

Thanks.

Re: Traffic shaping

jab1 — Thu, 03 Oct 2024 11:59:35 GMT

AFAIK, Plusnet do not do any traffic shaping, and from my experience when I was with PN, neither do BT/OR, but I can't confirm/deny that.

Re: Traffic shaping

Townman — Wed, 09 Oct 2024 15:12:41 GMT

Plusnet used to implement traffic shaping but they do so no longer.

Could this be bandwidth limiting in your download tool?

Re: Traffic shaping

Cliff_g — Wed, 09 Oct 2024 17:47:37 GMT

Hi, thanks for the suggestion.

No, all my email accounts from other providers are fine, even one on another of the same ISP's servers. Using the same email client, or a different one on my tablet. Have done all the possible end-to-end trials we can with results suggesting it could be my end (local cabinet/Plusnet gateway), or their end (the same slowness is shown not only on email but on file download using cPanel file manager (but ok on direct https) or the backend https configurator of a Wordpress site I run (but not the frontend direct https access), but in the end thwre's no single point of failure obvious.

We've concluded it's something strange about the routing between these two IP addresses. I'm currently getting to grips with Wireshark to see if I can see what's happening. The real-time traffic speed indicator I run shows the traffic is very peaky - constant hunting from 800 to 200 kbps and back with 500 as only an average, and my broadbamd line happily does 40 Mbps on https and other email servers. So it looks like either some dropped packets, lost ACKs, packets with almost nothing in the application layer section of the packet, or some such.

If I get to the bottom of it, I'll post.