Networking Essentials: Devices, Protocols, Topologies

Network Fundamentals: LANs and WANs

• A Local Area Network (LAN) covers a small geographical area, such as a single site or building (e.g., a school or a college).

• A Wide Area Network (WAN) covers a large geographical area. Most WANs are formed by connecting several LANs, with the internet being a prime example.

Virtual Private Networks (VPNs) Explained

A Virtual Private Network (VPN) is programming that creates a safe, encrypted connection over a less secure network. It provides business travelers with secure access to software applications hosted on proprietary networks. To gain access to a restricted resource through a VPN, the user must be authorized to use the VPN application and provide one or more authentication factors, such as a password.

Understanding Network Topologies

• Token Ring Topology

  Token Ring networks are known for having no collisions and being very efficient. However, a significant drawback is that if one piece of equipment fails, the entire network can be affected.

• Star Topology

  The Star topology is considered the most reliable and secure network configuration, but it is also the most expensive to implement.

What is a Server?

A server is a computer or computer program that manages access to a centralized resource or service within a network, e.g., a file server or a web server.

Network Collisions: Causes and Prevention

In a half-duplex Ethernet network, a collision occurs when two devices on the same Ethernet network attempt to transmit data at exactly the same time.

If two devices transmit simultaneously, a collision occurs, and both devices detect it. Each device then waits a random amount of time and retries until the transmission is successful. Collisions are most common on bus topologies and least probable in a star topology.

Domain Name System (DNS) Basics

A DNS server is a computer server that contains a database of public IP addresses and their associated hostnames. In most cases, it serves to resolve, or translate, those names to IP addresses as requested. DNS servers run special software and communicate with each other using special protocols. It acts like a decoder for web addresses.

Intranet: Private Network Communication

An intranet is a local or restricted communications network, especially a private network created using World Wide Web software.

Internet Service Providers (ISPs)

An Internet Service Provider (ISP) is the industry term for the company that provides you with access to the internet, typically from a computer. Examples include Movistar, Vodafone, and Euskaltel.

Understanding IP Addresses

An IP address is a 32-bit number that uniquely identifies a host (computer or other device, such as a printer or router) on a TCP/IP network.

An IP address serves two main functions: host or network interface identification and location addressing.

IP addresses are normally expressed in dotted-decimal format, with four numbers separated by periods, such as 192.168.123.132.

For example, 192.168.123.132 is a valid format, while 1234.5678.0.1.8 is incorrect.