What is MTU?

The Maxium Transmission Unit (MTU) is the largest data packet size, measured in bytes, that can be transmitted over a network.

Packet (packet) is the basic unit of information transmitted through all modern computer networks, and also in other telecommunication networks. Packages can be fixed or variable, depending on the network form and protocol (or a unified format). Each package, regardless of size, contains not only the data but also the header (header) which has the source and destination IP addresses.

If larger than MTU, the message will be divided into smaller packets before being sent. The split will slow down the transmission speed. Ideally, the MTU should be equal to the smallest MTU of all connected networks between the computer and the destination computer to which the message is sent.

MTU varies depending on the protocol and the network. For example, Ethernet (most commonly used in the LAN protocol) has a fixed MTU of 1500 bytes. ATM (Asynchronous Transfer Mode) has a fixed MTU of 48 bytes and PPP (point to point protocol) with MTU is usually in the range of 500 to 2000 bytes.

The MTU of the Internet connection is the smallest MTU of any shortcut from the address to the receiving address, which is the largest MTU value that can be turned off without the package being fragmented. Shortcut is a path or route across the route to the destination.

Path MTU Discovery is a technique to find a path between two IP addresses (ie two computers) to avoid packet fragmentation. This technique takes advantage of the feedback gained from sending a series of packages with increasing size.

See more:

1. Knowledge of TCP / IP network protocols
2. The Internet is decentralized - something rivaling the Internet we still know, is already here
3. Basic measurement units in computers