W2783 Basic Networking

Within these castle walls be forged Mavens of Computer Science ...

— Merlin, The Coder

Introduction

When working with computer devices, it's important that you understand the concept of networking. Networks are mainly focused on the hardware of computers. They connect devices together, allowing them to share data, software services, and other forms of communication. Historically, computer networks are framed in the context of a business or institution because they need a specialized network for resource sharing, such as printers, scanners, or expensive software.

In this lesson, we'll be taking a look at the components of a network and its shared computer devices to understand how computer networking works in principle.

Types of Networks

It's helpful to think of a network as simply the connection of many physical devices at once using wires or wireless media to transmit the signals. At its most elementary level, a network can be thought of as plugging in a printer to a computer.

As a result, many different types of networks exist, depending on their scope of spread. For example, one of the smallest networks is called PAN, which stands for Personal Area Network. This refers to the network many people occupy for their personal use, typically consisting of a computer, one or two monitors, a router, and a remote server.

At the next level is the LAN, which stands for Local Area Network. These are typically used in schools and offices where several computers are connected, allowing devices to be shared (normally printers in these types of settings). Beyond this layer is the MAN, which stands for a Metropolitan Area Network. This includes networks the size of well-populated cities such as the telephone lines in NYC. The largest network is called the WAN or Wide Area Network, which can cover any distance, the most common example being the Internet itself.

Public vs. Private Networks

The Internet serves as an interesting case study for a computer network because it's meant to be a network that spans the entire globe and is supposed to be available to the public. This leads to the distinction between public and private networks. Many companies, for example, have data that they want to share privately with only those in their network. This means someone outside the network cannot easily connect to it and access all the data for unauthorized use.

This distinction leads to the idea of a VPN. You might have heard of the term VPN. It stands for Virtual Private Network. Essentially, it allows users to connect to a private network virtually. These are an advantage when employees need to access work files from home. They can use a VPN to connect to their companies' private networks virtually.

Many complexities remain among the varied networks mentioned above; however, if you keep those general distinctions in mind, you'll understand computer networks on a basic level.

Quiz

1 Put the following networks in order from smallest to largest.

	PAN, LAN, WAN, MAN
	LAN, MAN, WAN, PAN
	PAN, LAN, MAN, WAN
	PAN, WAN, MAN, LAN

2 Which of the following is a real way for computers to connect to a network?

	Shared hardware such as CPUs
	Shared specifications such as RAM
	Proximity by region
	Wires such as Ethernet cables

3 True or False: Companies typically have public networks.

	True
	False

4 True or False: A VPN allows access to private networks remotely.

	True
	False

Components of a Network

Networks require several pieces of hardware to operate effectively. As defined before, a network is the connection of several physical devices, typically computers with shared resources. Switches control these computers and allow them to communicate with each other over a network . A type of equipment similar to switches is known as a router.

You might have heard of Internet routers. These simply communicate data between networks through either a LAN cable (Ethernet) or WiFi (Wireless Ethernet) system. Routers are integral to how the Internet runs because they connect an individual PAN or LAN to the world-wide web. They are usually programmed to operate at high efficiency while managing the traffic of data packets between the networks.

You might've also heard of an access point. In computer networking, access points can be thought of as a way to quickly bring new devices into a network without the need for cables. These improve the flexibility of networks within a business setting as users roam from one device to the next.

Finally, the servers are simply computers that distribute shared data (e.g., files, programs, and other media) to all the devices on the network. Their main function is to fulfill requests sent from the client or an application by performing a service.

These all lend themselves to the idea of Network Topology. We won't go too in-depth here, but know that network topology essentially refers to how the devices of a network are connected. Just picture them as routers and switches that interact with each other. Common patterns include the Line, Star, and Mesh. You can see these in the image below to understand it in abstract terms.

Network topology example patterns

Quiz

1 What are the switches used for?

	Control computers and allow them to communicate within a connected network
	Communicate with computers outside of their own network
	Control the flow of data coming into the network from the outside
	Connect two computers or devices via Ethernet

2 What is the purpose of a router?

	Works within a network to manage the connections between devices
	Communicates between networks and manages the flow of data or web traffic
	Serves as a central location for shared data that can be accessed within the network
	Allows computers to form a wireless connection to the network

3 True or False: Access points can be used to increase the flexibility of connecting devices to a network.

	True
	False

4 True or False: Devices in a network are connected using network topology.

	True
	False

Identifiers

An Identifier is a portion of the TCP/IP address for labeling the host network, and generally consists of 3-digit numbers separated by decimals. Possibly the most famous one is known as the IP address, which stands for Internet Protocol. This ID can be classified under commercial, institutional, or administrative networks.

It is a unique identifier given to every device connected to the Internet. These numbers were assigned by the Internet Assigned Numbers Authority to keep track of online devices. The number of IPs in the world is 2³² on IP version 4 because every IP is 32 bits long.

Another identifier for devices is called the MAC Address (Media Access Control Address), which is simply assigned to a computer or device when it is manufactured. It's sort of a physical version of an IP address. The number of MAC addresses available in the world is 2⁴⁸ because every MAC address is 48 bits long.

Protocols

A Protocol is considered an algorithmic set of directions that control how data is transmitted across devices belonging to the same network. This enables connected devices to exchange information even when their internal processes or structural design are different. Network protocols break down processes into smaller chunks known as functions that work together to complete a bigger task. A few examples are ISO, W3C, and IEEE.

In terms of protocols, there are a few to keep in mind. For example, the ARP , which stands for Address Resolution Protocol. It is a protocol to convert an IP into the physical MAC. The reverse can be done with RARP (Reverse Address Resolution Protocol).

Within networks, several identifiers and protocols are used to distinguish between devices and to define how those devices are able to communicate. When the Internet grew larger, IDs were grouped into an IPv6 system instead of the IPv4, which had only 32 bytes.

DNS Servers

Finally, there is the DNS Server, which stands for Domain Name System, and is vital to how the world-wide web works. This is because the DNS server takes the HTTPS address and URLs as inputs for the web browser, and translates them into the necessary IP address or server that is hosting the website for the computers on the network (aka the Internet).

Basically, it converts a domain name like www.sampleurl.com into an IP address such as 83.127.104.119. The DNS server is a translator that directs to the site through the sent domain request.

We have many moving parts and complexities involved in networking, but these are essentially the core concepts to keep in mind. Try thinking of how all these parts combine together and when you feel comfortable, continue reading further into how computer networks operate.

Quiz

1 What is a protocol?

	A means of physically identifying hardware when it is manufactured
	An algorithmic set of instructions on how computers in a network can talk to each other
	A way of translating web addresses or URLs into IP addresses
	A way of managing the devices that are on the Internet

2 How are the devices on the Internet identified?

	Using the DNS system
	Using the ARP system
	Using the MAC address
	Using the IP address

3 True or False: An IP address can be converted into a MAC address using RARP.

	True
	False

4 True or False: Two main identifiers and three main protocols are used in computer networking.

	True
	False

Key Concepts

Key Concepts

• Types of Computer Networks
  • A network is simply the connection of several devices and can span anywhere between local and global areas
  • Networks can be public or private, with the Internet being a quintessential example of a public network
  • Networks are made to quickly communicate files and programs between multiple devices such as computers, printers, or scanners

• Components of a Network
  • Switches allow control and communication between computers in a network
  • Routers allow communication and traffic between networks
  • Access points allow computers to join a network wirelessly
  • Servers hold shared data within a network for the devices to use

• Identifiers and Protocols
  • Identifiers are used in networking to keep track of certain devices; protocols are sets of instructions on how devices communicate
  • IP addresses and MAC addresses are used to track devices on the Internet and as the devices are being manufactured
  • ARP and RARP are two protocols that allow the conversion between IP and MAC and vice versa
  • DNS or Domain Name System Server is a common protocol used to convert URLs into IP addresses, a critical protocol for the Web