Network Fundamentals: Addressing, Topologies, and Hardware

Fundamentals of Computer Networking

What is a Computer Network?

A computer network is a set of interconnected devices (computers, servers, peripherals) designed to share resources and exchange information efficiently.

Network Classification by Size (Scope)

Networks are classified based on their geographical scope:

• LAN (Local Area Network): Covers a small, localized area, such as a home, office, or school campus.
• MAN (Metropolitan Area Network): Spans a city or large campus.
• WAN (Wide Area Network): Extends over a large geographical distance, often connecting multiple LANs (e.g., the Internet).

Network Classification by Property

Networks can be categorized based on access rights and ownership:

• Public Networks: Networks where access is available to the general public (e.g., public Wi-Fi hotspots).
• Private Networks: Networks that utilize private IP address space. These addresses are commonly used internally within organizations or homes.
• Virtual Private Networks (VPNs): A VPN extends a private network across a public network, such as the Internet, allowing users to send and receive data securely as if their computing devices were directly connected to the private network.

Network Topologies: Bus, Ring, and Star

Network topology defines the physical or logical arrangement of nodes and connections. Key topologies include:

• Bus Topology (Linear): All machines are connected to a single, shared transmission medium called the bus.
• Ring Topology: Nodes are connected in a closed-loop configuration, where data travels sequentially from one node to the next.
• Star Topology: All nodes are directly connected to a common central device (usually a switch or hub). This is the most common modern topology.

Ethernet Standards and Classification

Ethernet standards like 100Base-T and 1000Base-T define speed and media type:

• The number (e.g., 100 or 1000) indicates the maximum transmission speed in Megabits per second (Mbps).
• The letter T indicates the type of cable used: Twisted Pair copper cabling.

Types of Network Cabling

The primary types of physical network cables are:

• Twisted Pair Cable: Consists of 8 copper wires twisted together in 4 pairs. Common types include:
  • UTP (Unshielded Twisted Pair)
  • STP (Shielded Twisted Pair)

  This cable typically uses an RJ45 connector at each end.

• Optical Fiber Cable: A cable containing one or more optical fibers that transmit data using light pulses. Fiber optic cables offer significantly higher bandwidth and longer transmission distances than copper.

Wireless Network Technologies

Wireless networks use radio waves for data exchange:

• Wi-Fi (Wireless Fidelity): A local area wireless technology that allows electronic devices to exchange data or connect to the internet using radio waves.
• Bluetooth: A short-range wireless technology that uses short-wavelength UHF radio waves, primarily for connecting personal devices (e.g., headphones, keyboards).

Essential Elements of a Local Area Network (LAN)

A functional LAN requires several key components:

• End Devices: Computers, servers, printers, and other peripherals.
• Network Interface Card (NIC): Hardware installed in devices to allow connection to the network medium.
• Interconnecting Devices: Switches, hubs, or routers used to manage traffic flow.
• Transmission Media: Cables (Twisted Pair, Fiber) or wireless signals.

Understanding the MAC Address

The Media Access Control (MAC) address is a unique physical identifier permanently assigned to a network interface card (NIC) for communications within a physical network segment.

Hub vs. Switch: Which is Faster?

The Switch is more modern and significantly faster than a Hub because it intelligently forwards data only between the two computers involved, unlike a Hub which broadcasts data to all connected devices.

TCP/IP Protocol Suite

The Transmission Control Protocol/Internet Protocol (TCP/IP) is the fundamental set of protocols that governs internet communication. It allows communication among computers with different operating systems and various types of communication methods. This protocol suite is essential for the operation of the Internet.

IP Addressing and Classification

An IP address (Internet Protocol address) is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. It identifies the host and its location on the network.

IP Address Structure

An IPv4 address consists of four sets of numbers (octets) separated by dots, with each number ranging from 0 to 255.

Classification of IP Networks

Historically, IP networks were classified into major categories based on the size of the network they could support:

• Class A
• Class B
• Class C