The Identification Header is a field in an IP packet that helps identify fragments belonging to the same original packet. It is mainly used when a large IP packet gets split into smaller pieces during transmission.

Each fragment carries the same identification value. The receiving device uses this value, together with other information, to put the fragments back together correctly.

How It Works

• A large IP packet is split into smaller fragments.
• Each fragment receives the same identification value.
• The fragments travel through the network.
• The receiving device uses the value to recognize related fragments.
• The fragments are reassembled into the original packet.

Common Uses

• Identifying fragments of an IPv4 packet.
• Reassembling fragmented network traffic.
• Helping routers and receiving devices handle large packets.
• Supporting communication across networks with different packet size limits.

Related Terms: IP Packet, IPv4, Packet Fragmentation, Fragment Offset, More Fragments Flag, MTU, IP Header, Network Layer, Datagram, Packet Reassembly

Related Entries

• Connectionless Protocol
• Identification Header
• IP Address
• OSI
• Protocol Stack