Explain IPV4 Header format in detail.
2 years ago
Computer Network
- Version(4 bits): Indicates the version number, to allow the evolution of the protocol.
- Header Length (4 bits): Length of header in 32-bit words. The minimum value is five for a minimum header length of 20 octets.
- Service: The Service field contains an 8-bit binary value that is used to determine the priority of each packet.
- Total length: total datagram length in octets.
- Identifier (16 bits): A sequence number that, together with the source address, destination address, and user protocol, is intended to identify a datagram uniquely.
- IP Destination Address: The IP Destination Address field contains a 32-bit binary value that represents the packet destination Network layer host address.
- IP Source Address: The IP Source Address field contains a 32-bit binary value that represents the packet source Network layer host address.
- Time-to-Live: The Time-to-Live (TTL) is an 8-bit binary value that indicates the remaining "life" of the packet. The TTL value is decreased by at least one each time the packet is processed by a router (that is, each hop)
- Protocol: This 8-bit binary value indicates the data payload type that the packet is carrying. The Protocol field enables the Network layer to pass the data to the appropriate upper-layer protocol.
- Header checksum (16 bits): An error-detecting code applied to the header only. Because some header fields may change during transit (e.g., time to live, segmentation-related fields), this is reverified and recomputed at each router. The checksum field is the 16-bit one's complement addition of all 16-bit words in the header. For purposes of computation, the checksum field is itself initialized to a value of zero.
- Options (variable): Encodes the options requested by the sending user.
Dipti KC
Dec 26, 2022