Hello
I have connected PlusNet One Hub (https://openwrt.org/toh/bt/homehub_v5a) OpenWrt 21.02
to Virgin Media Hub 3 in modem mode. All works OK except for a speed of the Internet connection.
Virgin Media fibre link speed is 200Mbps but in my above setup I can only get around 50/60Mbps.
(testing on wired connection to PlusNet Hub One).
Is there something I need to enable for this setup to enable full link speed?
Try enabling packet steering:
You can find this setting under: Network > Interfaces > Global network options.
But I doubt a 500 MHz CPU device will get 200 Mbps.
Thanks but I already have this option enabled.
The BTHub5 isn't very fast as a router, enabling software flow-offloading should get you your desired throughput though.
Longer term I would suggest looking for a faster device though, as flow-offloading comes with its own set of quirks, it's always better to use a router that can cope with the required throughput without resorting to hacks like that.
Have you studied section 7.12 of the installation guide?
https://openwrt.ebilan.co.uk/viewtopic.php?t=266
https://www.dropbox.com/sh/c8cqmpc6cacs5n8/AAA2f8htk1uMitBckDW8Jq88a?dl=0
You will have to replace the HH5a if you wish to achieve 200 mbps WAN top LAN throughput.
Edit with corrections thanks to bill888
That's not exactly correct - I've been experimenting with one of my HH5As and these are the results between 2 OpenWRT routers as I only have a 100mbit contract:
root@OpenWrt:~# grep name /etc/board.json
"name": "BT Home Hub 5A"
"name": "wifi",
"name": "dsl",
"name": "dimmed",
root@OpenWrt:~# iperf3 -c 192.168.1.1
Connecting to host 192.168.1.1, port 5201
[ 5] local 192.168.1.152 port 42600 connected to 192.168.1.1 port 5201
[ ID] Interval Transfer Bitrate Retr Cwnd
[ 5] 0.00-1.00 sec 23.7 MBytes 198 Mbits/sec 0 354 KBytes
[ 5] 1.00-2.02 sec 24.1 MBytes 198 Mbits/sec 0 445 KBytes
[ 5] 2.02-3.02 sec 24.9 MBytes 210 Mbits/sec 0 475 KBytes
[ 5] 3.02-4.03 sec 24.5 MBytes 204 Mbits/sec 0 498 KBytes
[ 5] 4.03-5.01 sec 24.4 MBytes 208 Mbits/sec 0 498 KBytes
[ 5] 5.01-6.02 sec 25.5 MBytes 211 Mbits/sec 0 498 KBytes
[ 5] 6.02-7.01 sec 24.4 MBytes 206 Mbits/sec 0 522 KBytes
[ 5] 7.01-8.04 sec 24.8 MBytes 202 Mbits/sec 0 522 KBytes
[ 5] 8.04-9.04 sec 24.8 MBytes 209 Mbits/sec 0 522 KBytes
[ 5] 9.04-10.00 sec 25.5 MBytes 222 Mbits/sec 0 522 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 246 MBytes 207 Mbits/sec 0 sender
[ 5] 0.00-10.00 sec 246 MBytes 206 Mbits/sec receiver
The host on 192.168.1.1 that is facing the internet is a Linksys EA7500v1 (21.02.0) and the client HH5A is a snapshot build. I've enabled Software flow offloading and have added a custom script that I got from this post
Unless I have misread your newest test results reporting 200 Mbit/sec, I don't think you are actually testing the throughput (WAN to LAN) of the HH5a if 192.168.1.1 is your Linksys and the 192.168.1.152 is the interface of the HH5a wired to the Linksys.
You will indeed see 200+ mbits/sec speeds between the interfaces of those two routers using your 'incorrect' test method.
Try repeating the test with two computers running iperf3. One wired to WAN (you could use linksys instead of a PC), and other computer on LAN side of HH5a, for true measurement of throughput.
I see the errors in my ways then 
Before the said patch was applied the results were abominable and I thought that it was just my connection that was capped and the iperf results looked great - here are the results from my laptop going to the Linksys through HH5a:
Connecting to host 192.168.1.1, port 5201
[ 4] local 192.168.88.177 port 9046 connected to 192.168.1.1 port 5201
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-1.00 sec 10.1 MBytes 84.6 Mbits/sec
[ 4] 1.00-2.00 sec 10.5 MBytes 88.2 Mbits/sec
[ 4] 2.00-3.01 sec 11.0 MBytes 92.0 Mbits/sec
[ 4] 3.01-4.00 sec 10.2 MBytes 86.4 Mbits/sec
[ 4] 4.00-5.00 sec 10.5 MBytes 88.0 Mbits/sec
[ 4] 5.00-6.00 sec 11.1 MBytes 93.3 Mbits/sec
[ 4] 6.00-7.00 sec 10.4 MBytes 87.1 Mbits/sec
[ 4] 7.00-8.00 sec 10.9 MBytes 91.0 Mbits/sec
[ 4] 8.00-9.00 sec 10.9 MBytes 91.4 Mbits/sec
[ 4] 9.00-10.00 sec 11.0 MBytes 92.2 Mbits/sec
[ 4] 10.00-11.00 sec 10.8 MBytes 90.1 Mbits/sec
[ 4] 11.00-12.00 sec 10.6 MBytes 88.9 Mbits/sec
[ 4] 12.00-13.00 sec 11.2 MBytes 94.5 Mbits/sec
[ 4] 13.00-14.01 sec 10.2 MBytes 85.6 Mbits/sec
[ 4] 14.01-15.00 sec 10.8 MBytes 90.6 Mbits/sec
[ 4] 15.00-16.00 sec 10.5 MBytes 88.0 Mbits/sec
[ 4] 16.00-17.00 sec 10.1 MBytes 84.9 Mbits/sec
[ 4] 17.00-18.01 sec 11.0 MBytes 91.9 Mbits/sec
[ 4] 18.01-19.01 sec 11.5 MBytes 96.5 Mbits/sec
[ 4] 19.01-20.00 sec 10.9 MBytes 91.9 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-20.00 sec 214 MBytes 89.9 Mbits/sec sender
[ 4] 0.00-20.00 sec 214 MBytes 89.8 Mbits/sec receiver
iperf Done.