MTU
Networking
The largest amount a link carries in one piece, headers included: 1500 bytes on ordinary Ethernet, which ip link show prints. Of those 1500 the IP header takes 20 and the TCP header 20 more, leaving about 1460 bytes of your data per packet — and the seven thousand or so packets of a 10 MB archive. It is not a constant: a tunnel or a VPN lowers it, which is why a path that carries small packets perfectly can stall on large ones. ping -M do -s 1472 fills a 1500 MTU exactly and fails at the next byte, which measures it with no second machine.
Also written: maximum transmission unit