what is the best MRU & MTU in modem for downloading
December 18th, 2021
It won’t make downloading faster. MTU is used for efficiency, and therefore it can be detrimental increasing it, as larger packets that fail will have to be re-transmitted in their entirety. If you have no problem with your network dropping data, etc, leave it alone.
If you’re not getting your full bandwidth download speed, try using wired over wireless, pause security software that may be checking data clarity, use download managers so you can download with multiple connections, etc, but MTU isn’t the way to go.
Setting the optimal MTU can help a little and is easy enough.
Open a command window and do this:
type ping www.google.com -f -l 1492
if you get a message 'Packet needs to be fragmented but DF set.' then reduce the number by 10 and try again
if you get a message 'Reply from 123.3.1.53: bytes=XXXX time=XXms TTL=XX' then add 2 to the number and keep trying until the packet needs to be fragmented again
add 28 to the highest number that doesn't need to be fragmented and there's your optimal MTU
The 28 bytes are the IP/ICMP header size.
Actually, windows 7 take all this over and does what IT wants, not what you want.
You can disable that but you end up far worse than it was before.
W7 stuff Disabled = 3/10 speed
W7 enables = 8/10 speed
Mtu tweaks = possibly 8.5 to 9 /10
So it’s not really worth the faffing about with Win7.. XP was another matter though..