Communication Protocols and the OSI Reference Model

Overview - The Necessity of Protocols

In the fields of the Internet of Things, computer networks, and information and communication, we often mention the concept of "Communication Protocols". Simply put, it is a kind of "agreement" reached before communication between terminals via a network. This "agreement" enables computers composed of different manufacturers, devices, and operating systems to communicate as long as they adhere to the same protocol. Conversely, if different protocols are used, communication becomes impossible.

We can give an example: if two people use different languages to communicate over the phone, even if they hear each other's voices, effective communication cannot be achieved.

Protocol Standardization and Organizations

In the early stages of computer communication, systematic and standardization efforts were not given sufficient attention. People did not pay much attention to protocols, leading to many problems during development. Consequently, each manufacturer produced its own network products for communication. It is understandable that products from different manufacturers could not communicate with each other, causing great distress for users. If users adopted products from one manufacturer, they had to consistently use that manufacturer's network products; otherwise, they could not function. If a manufacturer went bankrupt or discontinued a product, the entire network equipment had to be replaced. This resulted in resource waste and significantly hindered the development speed of the industry.

In 1974, IBM released SNA (IBM Systems Network Architecture), making this systematic network architecture public. Subsequently, various manufacturers announced their own network architectures. However, because the architectures and protocols of different manufacturers were incompatible, effective communication remained impossible, even if physical connections were established.

In fact, standardization is ubiquitous in our daily lives. Power sockets, toilet paper, paper books, pencils, ballpoint pens, etc., all have standards. Imagine if there were no such standards, and the toilet paper we purchased came in various sizes, how much trouble it would cause in our lives. With the vigorous development of the network and computer world, people gradually realized the importance of compatibility. Therefore, ISO (International Organization for Standardization) established an international standard, OSI (Open Systems Interconnection Reference Model), to standardize communication systems.

Standardization organizations are divided into three major categories: International Standardization Organizations (e.g., ISO, ITU-T), National Standardization Organizations (e.g., ANSI in the USA, Standardization Administration of China, JIS in Japan), and Non-governmental/Industry Standardization Organizations (e.g., IETF, IEEE). In the real world, many excellent companies do not disclose their development specifications, preventing their technologies from gaining widespread adoption. Therefore, standardization is a task with long-term and significant impact on the future of the entire world.

Protocol Layering and the OSI Reference Model

When ISO was developing the standardized OSI, it conducted extensive and numerous discussions over a long period regarding factors related to network architecture. Ultimately, it proposed the OSI reference model as a design guideline for communication protocols. This model layers the necessary functions of communication protocols, making the entire complex network protocol simpler and clearer through these layers.

In this reference model, each layer receives information and services from the layer below it and is responsible for providing information and services to the layer above it. The agreement followed for interaction between adjacent layers is called an "interface". The agreement followed for information exchange within the same layer is called a "protocol". Protocol layering isolates each layer for independent use, enabling the construction of a system with extensibility and flexibility. West-HN Technology is committed to building a "Lego" model for IoT foundational hardware, also borrowing this mindset to expand our product lines.