Introduction to Computer Networks
A computer network represents the fundamental infrastructure on which the entire modern digital society relies. It enables the exchange of information, resources, and services between different independent computers.
Definition and Key Concepts
In the broadest sense of the term, a network is formed by a set of interconnected nodes through communication channels that can be physical or wireless.
Geographic Classification
Networks are traditionally classified based on their geographic extent to better understand their scales and uses.
The Local Area Network (LAN) covers a limited area, such as an office or a home, offering high transfer speeds and low latencies.
The Metropolitan Area Network (MAN) extends over an urban area and interconnects different local networks distributed in the same city.
The Wide Area Network (WAN) covers immense distances, at a national or global level, connecting entire countries, as in the case of the Internet.
Physical and Logical Topologies
Network topology defines how different devices are arranged and connected to each other within the infrastructure.
The star topology provides that all nodes are connected to a central device, such as a switch, which routes incoming traffic.
The bus topology uses a single shared channel to which all nodes connect in parallel, ideal for very simple networks.
The ring topology connects each node sequentially to the next, closing the circle to allow data circulation.
The mesh or mesh topology offers the highest fault tolerance, as nodes are interconnected with multiple paths.
Network Software Architectures
From the point of view of software and service organization, two main architectural models are distinguished.
The Client-Server architecture provides dedicated servers to offer resources and clients that request them.
The Peer-to-Peer (P2P) architecture positions all nodes at the same level, allowing each one to function as both a client and a server.
Essential Hardware Components
To realize a functioning physical network, specific hardware devices designed to route and process data are necessary.
The hub is a physical level device that is now obsolete, which forwards signals in broadcast to all ports indiscriminately.
The switch acts at the data link level, storing MAC addresses to forward packets exclusively to the destination node.
The router operates at the network level, connecting different networks and deciding the best route for data packets to travel.
Conclusions
Understanding networks and their architectures constitutes the starting point for anyone who wants to explore the world of Information Technology.