Max Premium

[#1]

I can't say - was that the router's default on installation, or did something make you change it?

[#2]

It was the draytek default which it has always been set at, just tried it set to 1500 and get the same results from the speedtest so I doubt it is that as the download speed issue only came to light when I started doing some testing at the weekend, as before that I was getting full line speed.

[#3]

It may be worth persevering with the 1500 MTU for a while longer, also if you are running an older version of Windows, then it may be worth running TCP Optimiser to see if any tweaks are necessary.

[#4]

Out of interest, what does this test show as your max MTU http://www.letmecheck.it/mtu-test.php ?

[#5]

Interesting - on my connection I get "The maximum MTU size for <my IP address> is: 1480". I've had errors and issues on my line for weeks, with the MTU at 1492 - I think I'll try a change to 1480 to see if anything improves.
<Edit> It's already at 1480. Dang.

[#6]

Did you try changing the MTU of your router and PC?
You should be able to use up to 1508 for ADSL, although you might get issues.

[#7]

It says 1500 which it is set to at the moment, but I highly doubt its MTU related.

[#8]

@ ANdyH
If that was aimed at me I'm on FTTC.

[#9]

I doubt it's congestion as I can't ever recall that affecting one's upload speeds.
It's almost like there is some limit placed on you (both 0.6Mb down/up) looking at your earlier TBB speed test:

@ Jaggies - Ah, sorry forgot this. So it will be 1500 max for you.

[#10]

@ AndyH
1492, Shirley?

[#11]

1500 will work - there's a detailed explanation here http://aa.net.uk/kb-broadband-mtu.html
One of the PN OPs told me this:

Quote

you should be able to manage a WAN MTU of 1508 and a LAN of 1500 with mss adjust disabled.

I've yet to try it though as every time I play with my MTU, it causes me issues.

[#12]

Yeah - I'm fairly certain it isn't the cause of my problems, and my router defaults to 1480 which may be why the "letmecheckit" site gave that as the maximum MTU size.
I'll maybe switch it to 1492 and retry that site later.

[#13]

The crucial thing is to make sure that the PC MTU is NOT higher than the router MTU.

[#14]

Yep and the router will have a WAN/LAN and Broadcast MTU - all of which should be whatever your PC is set to.

[#15]

@ JELV
Good point - I've never checked my PC's MTU.
OK - it's 1500. I've now reset it to 1480 - the BTW speedtester is still red, but the Thinkbroadband test is much better...

I'll monitor this over the next few days - there's an engineer scheduled to visit on 1/9/14 so I may be able to cancel if this fixes the issue. I'll resynch the modem when I'm next here during the daytime (Saturday) and check the FEC error count, as it's currently doing over 100 million a day...
And @ Bud - sorry for hijacking your thread...