TCP/IP in Detail

TCP/IP (Transmission Control Protocol/Internet Protocol) is the protocol suite used for communication between computers over interconnected networks, including the Internet.

Layers of TCP/IP

Layer	Main role	Examples
Application	Provides network services to applications	HTTP, FTP, SMTP, DNS
Transport	End-to-end delivery and reliability	TCP, UDP
Internet	Logical addressing and routing	IP, ICMP
Network Access	Transfers frames over the physical/local network	Ethernet, Wi-Fi

TCP

TCP is connection-oriented and reliable. It provides sequencing, acknowledgements, retransmission, flow control and congestion control.

Basic TCP communication

1. A connection is established using the three-way handshake: SYN → SYN-ACK → ACK.
2. Data is divided into segments and numbered.
3. The receiver acknowledges received data.
4. Lost data can be retransmitted.
5. The connection is closed after communication finishes.

IP

IP provides addressing and routing of packets between networks. IPv4 uses 32-bit addresses, while IPv6 uses 128-bit addresses.

Advantages

• Reliable communication through TCP.
• Routing across different networks through IP.
• Scalable and interoperable.
• Supports many application protocols.

In short: TCP provides reliable transport; IP provides addressing and routing.