Me too on a 2850vn. Have latest f/w for it but notice build date is earlier than available on here. Also the modem code is newer on here so may be worth a try?

@jonp73 what firmware and modem code do you have on your 2850 please?

Thanks

I think that I have just discovered why 2750 upload speeds are generally slower than the BT router, when using Speedtest.net.

With the BT router combination, I was getting upload speeds of greater than 8Mbps, but the 2750n won't go much higher than about 7Mbps.

The cause is Jumbo packets.

Running the speedtest.net test on the BT router, my PC sends frames with a payload of over 8000 bytes, but the 2750 can't handle this, and drops them. See the WAN >> Internet Access screen, which shows a Max MTU of 1492. This means that the PC then tries smaller frames, with a payload of 536 or 1072 bytes. The overheads are, therefore, much greater, so the throughput is consequently lower.

I will raise this with Draytek.

Mike.

Disregard my comments above. I was talking rubbish.

Having correctly set the QoS settings in the router, I am now getting an upload speed of about 8.4 Mbps using speedtest.net.

As for the jumbo packets, speedtest.net is still not able send the large frames. However, the Think Broadband speed tester is successfully sending frames with a payload of 8192 bytes, using a frame length of 8246 bytes. The Do Not Fragment flag is set in the IP header, but the Acks that I am getting back indicate that, perhaps, something is fragmenting the frame, somewhere. For each frame that is sent, I am getting back 8 Acks, for 1072 bytes.

I think that I will give up, now, even though I don't understand what is going on. At least my 2750 is giving me better speeds than the BT combination on both speedtest.net and TBB speed tests. The BT speed tester is too unreliable to take any notice of.

Mike.

I'm changing my mind, again.

I now think that the 2750n does support jumbo packets, but some connections via BT don't. I have just rebooted my 2750n, and picked a different connection. Speedtest.net is giving my an upload speed of about 9.1 Mbps, which I think is pretty good for a 9,994kbps connection. On capturing the packets, I can see that my PC is sending frames with a payload of over 11,200 bytes on this connection.

I am guessing that my earlier tests with the BT router/modem happened to pick a connection that supports jumbo packets, but my 2750n test picked one that didn't.

Mike.

Hi Mike, so glad that you managed to fix the issue. I have been testing my upload on the 2750n on speedtest.net and generally i am getting between 6-7.5.

I was wondering if you could give me the QOS settings that you have, since i basically just deleted all of them in an effort to try and fix the upload. Also did u manually set the MTU size to anything.

Also if there are any other settings that u can recommend. What firmware are you also using. I am using the latest firmware available on the draytek support page.

Thanks in advance man.

just found some QoS settings on the bt infinity forums, followed them and rebooted the 2750n and got the following:



First time i have got over 8Mb/s in a long long time . Would be nice to get over 9Mb/s but I am still happy.