How does TCP/IP decide the size of an IP fragment? Explain.

TCP/IP protocol utilizes the name IP datagram to refer to an Internet packet. The amount of data carried into a datagram is not fixed. The senders select an amount of data which is suitable for a particular motive. Fragmentation is performed, if size of a datagram is larger than network MTU.

While a datagram is larger than the MTU of a network over that it is sent, the router divides the datagram in smaller pieces termed as fragments and sends each fragment separately. To fragment a datagram for transmission across the network, a router utilizes the network MTU and datagram header size to compute maximum amount of data which can be sent into each fragment and number of fragment which will be needed.