Computer Networking Fundamentals

What is Computer Networking?

Computer networking refers to interconnected computing devices that can exchange data and share resources with each other. These devices use a system of rules, called communications protocols, to transmit information over physical or wireless technologies. Computer networks have evolved from their early days as military and defense systems, to become indispensable for businesses today.

How Does a Computer Network Work?

At the heart of any computer network are nodes, which can be data communication equipment (DCE) like modems, hubs, or switches, or data terminal equipment (DTE) like computers and printers. The nodes are connected by links, which can be physical, like cable wires or optical fibers, or wireless, using free space. The nodes follow a set of rules or protocols to send and receive electronic data via the links.

What Do Computer Networks Do?

Modern computer networks can:

• Operate virtually, allowing the underlying physical network infrastructure to be logically partitioned into multiple "overlay" networks where nodes are virtually linked and data can be transmitted between them through multiple physical paths.
• Integrate on a large scale, connecting physically distributed computer networks and optimizing network functions through automation and monitoring to create one large-scale, high-performance network.
• Respond quickly to changing conditions, with many computer networks being software-defined, allowing traffic to be routed and controlled centrally using a digital interface.
• Provide data security, with in-built security features like encryption and access control, and the ability to integrate third-party solutions like antivirus software, firewalls, and antimalware.

Types of Computer Network Architecture

Computer network architecture can be broadly classified into two categories:

• Client-Server Architecture, where nodes may be servers or clients, with servers providing resources like memory, processing power, or data to client nodes.
• Peer-to-Peer Architecture, where connected computers have equal powers and privileges, with each device in the computer network able to act as either client or server.

Network Topology

The arrangement of nodes and links in a network is called network topology. Some common types of network topologies include:

• Bus Topology, where each node is linked to one other node only, and data transmission over network connections occurs in one direction.
• Ring Topology, where each node is linked to two other nodes, forming a ring, and data can flow bi-directionally.
• Star Topology, where a central server node is linked to multiple client network devices, which performs better as data doesn't have to go through each node.
• Mesh Topology, where every node is connected to many other nodes.

Types of Enterprise Computer Networks

Depending on the organization's size and requirements, there are three common types of enterprise private networks:

• Local Area Network (LAN), an interconnected system limited in size and geography, typically connecting computers and devices within a single office or building.
• Wide Area Network (WAN), covering larger areas such as large cities, states, or even countries.
• Virtual Private Network (VPN), an overlay private network stretched on top of the public internet.

Key Components of a Computer Network

A computer network is built with two basic blocks: nodes or network devices and links. The links connect two or more nodes with each other. The communication endpoints are often called ports.

Network Topology

The arrangement of nodes and links is called network topology. Some common types of network topologies include:

• Bus Topology: Each node is linked to one other node only.
• Ring Topology: Each node is linked to two other nodes, forming a ring.
• Star Topology: A central server node is linked to multiple client network devices.
• Mesh Topology: Every node is connected to many other nodes.

Types of Networks

We use different terms to refer to networks based on their size and characteristics. Some common types of networks include:

• Local Area Network (LAN): A network that covers a limited area like a house or school.
• Wide Area Network (WAN): A network that extends over a large geographic area and is composed of many, many LANs.
• Data Center Network (DCN): A network used in data centers where data must be exchanged with very little delay.

Networking Protocols

When computing devices are connected together in a network, they need protocols to communicate with each other. The devices use protocols to send and receive data and to manage the network. There are many networks that use other protocols that are more suited for their task.