The TCP/IP model, also known as the Internet Protocol Suite, is a conceptual framework used to enable communication over interconnected networks. It consists of four layers, each with distinct responsibilities, protocols, and functionalities. Here's a detailed description of its architecture:
1. Application Layer
Purpose: Provides services and interfaces for applications to interact with the network.
Key Functions:
Handles high-level protocols, data representation, encoding, and session management.
Enables end-user applications to send and receive data over the network.
Facilitates processes like file transfer, email, and web browsing.
Examples of Protocols:
HTTP/HTTPS: For web browsing.
FTP: For file transfers.
SMTP: For sending emails.
DNS: For domain name resolution.
SNMP: For network management.
Correspondence to OSI Model: Combines the functionality of the Application, Presentation, and Session layers of the OSI model.
2. Transport Layer
Purpose: Ensures reliable data transfer between devices.
Key Functions:
Segmentation and reassembly of data.
Error detection and correction.
Flow control and congestion avoidance.
End-to-end communication and session management.
Key Protocols:
TCP (Transmission Control Protocol):
Connection-oriented.
Ensures reliable delivery through acknowledgments, retransmissions, and sequencing.
Used for applications requiring high reliability (e.g., HTTP, FTP).
UDP (User Datagram Protocol):
Connectionless.
Provides faster but less reliable communication.
Used for real-time applications (e.g., VoIP, video streaming).
Correspondence to OSI Model: Maps to the Transport layer of the OSI model.
3. Internet Layer
Purpose: Handles the logical addressing and routing of data packets across networks.
Key Functions:
Defines IP addresses for devices.
Routes packets to their destination using IP addresses.
Handles fragmentation and reassembly of packets.
Ensures data reaches the correct host on a network.
Key Protocols:
IPv4/IPv6: For logical addressing and routing.
ICMP (Internet Control Message Protocol): For error reporting and diagnostics (e.g., ping).
ARP (Address Resolution Protocol): Resolves IP addresses to MAC addresses.
RARP (Reverse ARP): Resolves MAC addresses to IP addresses.
Correspondence to OSI Model: Maps to the Network layer of the OSI model.
4. Network Interface Layer (Link Layer)
Purpose: Manages the physical transmission of data over the network medium.
Key Functions:
Handles physical addressing (MAC addresses).
Defines how data is transmitted over the hardware, such as cables, switches, and wireless.
Manages framing, error detection, and access control.
Key Protocols:
Ethernet: For wired local area networks.
Wi-Fi (IEEE 802.11): For wireless communication.
PPP (Point-to-Point Protocol): For direct connections between two nodes.
Frame Relay: For WAN connections.
Correspondence to OSI Model: Combines the functionality of the Data Link and Physical layers of the OSI model.