🚀 go-pugleaf

Robert Wilkens <rwilkens@ccur.com> wrote:

> elel@iexist.flw.lucent.com (Eric L. Edberg) writes:
> >     Changing MTU and MSS will NOT affect throughput unless you
> >        have high CRC errors on the down or up stream paths.
> 
> This is just not true.
> 
> If you have your MTU set too small, packets will have to be fragmented.
> 
> Among other things, this means you'll probably duplicate or triplicate
> header information for each packet.

All the servers on ethernet you are on are using the 1500 bytes MTU
(maximum transmission unit), so it will send packets this size all the
way to your server (as far as I remember, I can not remember if it is
negotiated at start of TCP sessions though). So the server that will
have to fragment the packages will get extra loaded.

And remember, as TCP/IP packet header is large. An ICMP packet is 8
bytes. And TCP is 12 bytes (or is it 16 ?). So they make up about 1% of
all traffic.

BTW: A good ethernet card will do about 1100-1150 kb/sec using TCP/IP.
The rest up to the theoretical 1250 kb/sec (10Mbit = 8 bits * 1250kb) is
mostly protocol overhead. So on ethernet 10% is actually wasted.