History Leading to the TCP/IP Model

Source: Dev.to

The Early Networking Landscape

In the early days of computer networking, there was no single standard. Each vendor created its own proprietary protocols, making it difficult for devices from different manufacturers to communicate. This fragmented environment forced network engineers to act as translators, bridging incompatible systems much like using a dictionary between two languages.

IBM’s Proprietary Model: SNA

During the 1970s and 1980s, IBM dominated the market with its Systems Network Architecture (SNA). While IBM promoted SNA as the de‑facto standard, other vendors continued developing their own, incompatible networking models. The result was a patchwork of protocols that rarely worked well together.

The Push for Standardization: OSI Model

To address the chaos, the International Organization for Standardization (ISO) launched an effort to create a universal networking framework. This effort produced the Open Systems Interconnection (OSI) model, a seven‑layer architecture designed to enable devices from different vendors to interoperate.

The OSI model provided a formal, structured way to understand network functions. However, its complexity and the slow pace of adoption limited its practical impact.

The Practical Alternative: TCP/IP

Across the Atlantic, the U.S. Department of Defense needed a more pragmatic solution—one that could scale across diverse systems and remain reliable under critical conditions. The TCP/IP suite emerged not from a bureaucratic committee but from university volunteers seeking a simpler, more adaptable networking system.

Over time, TCP/IP proved to be more flexible and easier to implement than the OSI model, leading to its rapid adoption as the dominant networking architecture.

Coexistence and the Shift to TCP/IP Dominance

For a period, many organizations ran both OSI and TCP/IP stacks side by side. Eventually, the simplicity and practicality of TCP/IP won out, and the OSI model receded into the background. Today, TCP/IP remains the foundational model for modern networking.

Summary

• 1970s‑80s: IBM’s SNA dominated but created vendor lock‑in.
• Late 1970s‑80s: ISO developed the OSI seven‑layer model to standardize networking.
• 1970s‑80s: University researchers, supported by the U.S. DoD, created the TCP/IP suite.
• Result: TCP/IP’s simplicity and adaptability led it to become the universal networking standard we use today.