what is mtu

MTU stands for Maximum Transmission Unit, which is the largest amount of data that can be transmitted in a single packet on a network. It is a parameter that applies to communications protocols and network layers, and is specified in terms of bytes or octets of the largest protocol data unit (PDU) that the layer can pass onwards. The MTU is important because it determines the maximum size of data that can be transmitted across a network without fragmentation. If a packet is larger than the MTU, it is fragmented into smaller packets to be transmitted across the network, and then reassembled at the receiver. The MTU is associated with Ethernet protocol and is referred to as protocol data. The size of an IP packet includes IP headers but excludes headers from the link layer. The MTU is usually fixed by standards, such as Ethernet, or decided at connect time by systems, such as point-to-point serial links.