MTU (Maximum Transmission Unit) is similar to MRU (Maximum Receive Unit),
except instead of setting receive packet size, it sets the maximum size of
transmitted packets. Any messages larger than the MTU
divided into smaller packets before being sent. It is 576
for PPP (Point-to-Point Protocol)
protocol and 1500 for Ethernet. The optimimum value is the
largest that does not require further splitting for any hop of the packet journey.