- 2071 Shrawan · 4 marks
Short note: IP
Short answer
IP is the connectionless, unreliable, best-effort network-layer protocol that provides logical addressing, routing, and fragmentation. Its IPv4 header includes version, IHL, TTL, protocol, checksum, and source/destination addresses; TCP and UDP handle reliability.
Write a short note on IP.
IP (Internet Protocol) is the network-layer protocol of TCP/IP that delivers packets (datagrams) from a source host to a destination host across interconnected networks. It is connectionless, unreliable and best-effort: it gives no guarantee of delivery, ordering or duplicate protection; higher layers (TCP) handle these.
Main functions
- Logical addressing (32-bit IPv4 address), routing, and fragmentation/reassembly.
IPv4 header (20 to 60 bytes)
| Field | Size | Purpose |
|---|---|---|
| Version | 4 bits | 4 |
| IHL | 4 bits | Header length in 32-bit words |
| Type of service | 8 bits | Priority / DSCP |
| Total length | 16 bits | Header + data (max 65,535 B) |
| Identification | 16 bits | Identifies fragments of a datagram |
| Flags (DF, MF) | 3 bits | Don't fragment, more fragments |
| Fragment offset | 13 bits | Position of fragment (units of 8 B) |
| TTL | 8 bits | Hop limit, decremented by each router |
| Protocol | 8 bits | 6 TCP, 17 UDP, 1 ICMP |
| Header checksum | 16 bits | Error check on the header only |
| Source / destination address | 32 bits each | IP addresses |
| Options + padding | variable | Optional features |
IP works with ICMP (errors), ARP (address mapping) and IGMP (multicast). IPv6 is its successor.
✓ Answer checked by Claude Opus 5.5 (high effort)