Various functions of IP Protocol are : -

1. Addressing -

   • IP packet headers contain addresses that identify the sending computer and the receiving computer.

   • Routers use this information to guide each packet across communication networks and connect the sending and receiving computers.

1. Reassembly -

   • Messages between computers are broken into packets.

   • Since most messages are too big to fit in one packet, and since packets aren't sent in any organized order.

   • So they must be reassembled as they arrive at the recipient.

   • IP dictates how packets are reassembled into usable messages.

1. Timeouts -

   • Each IP packet contains a Time to Live (TTL) Field.

   • Every time when router handles a packet, TTL field is decremented.

   • If TTL reaches zero then packet is discarded.

   • This prevent the packet from running in circles forever and flooding a network.

1. Fragmentation -

   • IP Packets may be split, or fragmented into smaller packet.

   • This permits a large packet to travel across a network which can only handle smaller packets.

   • IP Fragments packets transparently.

1. Options -

   • IP includes optional features such as allowing the sending computer to decide the path.

   • To trace the path they take.

   • To include added security in the packets.