TCP/IP model

TCP/IP model. The TCP/IP model is a conceptual framework used to standardize communications between computers in a network, particularly the Internet. It originated from research funded by theUnited States Department of Defense and has become the foundational architecture for global internetworking. The model organizes protocols into a layered suite, enabling interoperability among diverse hardware and software systems.

Overview

The model provides a structured approach to data transmission, abstracting complex processes into functional layers. Each layer handles specific tasks, from physical connection details to high-level application data, ensuring reliable communication across networks like the ARPANET. This layered design, championed by pioneers such as Vint Cerf and Bob Kahn, facilitated the evolution of the modern Internet. The suite's protocols govern everything from routing packets across the NSFNET to delivering email via SMTP.

Layers

The model traditionally consists of four layers, though some descriptions merge or expand these. The **Link Layer** deals with physical transmission over media like Ethernet or Wi-Fi, interfacing directly with hardware from companies such as Cisco Systems. The **Internet Layer**, using protocols like IP, is responsible for addressing and routing packets across networks, a function critical to operations of ICANN and IANA. The **Transport Layer**, with TCP and UDP, ensures end-to-end communication control and reliability for services like those run by Google. The **Application Layer** encompasses user-facing protocols such as HTTP for the World Wide Web and FTP for file transfers.

Protocol suite

The suite comprises numerous protocols that operate across the layers. Core internetworking is handled by IPv4 and IPv6, managed by organizations including the Internet Engineering Task Force. Routing between autonomous systems relies on protocols like BGP, essential for the backbone infrastructure of AT&T. The Domain Name System translates human-readable names to IP addresses, a system coordinated globally by entities like Verisign. Security protocols, including TLS developed by Netscape, and authentication methods like Kerberos from MIT, operate within this framework.

Comparison with OSI model

The TCP/IP model is often contrasted with the seven-layer OSI model developed by the International Organization for Standardization. While the OSI model is a more detailed theoretical standard, the TCP/IP model is derived directly from operational practice on the ARPANET. Key differences include the TCP/IP model's consolidation of the OSI's Physical Layer and Data Link Layer into a single Link Layer, and its combination of the Session Layer, Presentation Layer, and Application Layer. The practical success of the TCP/IP model, evidenced by the Internet, has made it the de facto standard over the more prescriptive OSI model.

History and development

Development began in the 1970s under the auspices of the Defense Advanced Research Projects Agency. Key milestones included the specification of TCP in 1974 by Vint Cerf and Bob Kahn, and the formal adoption of the TCP/IP protocol suite as the standard for the ARPANET on January 1, 1983, known as Flag Day (computing). This transition was supported by the development of the Berkeley Software Distribution UNIX, which included integrated TCP/IP networking. The subsequent expansion of the National Science Foundation Network and the commercialization led by companies like MCI Communications cemented its global dominance.

Applications and usage

The model underpins virtually all modern networked applications. It enables the World Wide Web via HTTP and HTTPS, email systems using SMTP and IMAP, and voice-over-IP services like those offered by Skype. Cloud computing platforms from Amazon Web Services and Microsoft Azure rely entirely on its protocols for infrastructure. The proliferation of the Internet of Things, involving devices from Samsung and Apple Inc., further extends its application. Its design principles continue to influence new networking standards developed within forums like the Internet Society. Category:Internet protocols Category:Network architecture Category:Computer networking