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Computer Science

Networks and the Internet (Part 2)

Article contents:

Internet Structure and Services

The internet is by far the largest computer network ever created. At its simplest level, it is a collection of LANs all joined together by routers and cabling all over the world. Using TCP/IP addressing, any computer on this huge network can talk to any other, thanks to the built-in data routing system.

The basic devices of the internet have already been discussed: the router, hub, and switch, as well as cabling. Once we leave the domain of the LAN, however, there is more complexity to how all of the devices are connected.

Individual residences and office buildings pay a telecom provider, or ISP, for a connection to the rest of the internet. If we imagine the internet as a series of buildings and roads, the cabling is the roads, the routers are the intersections, and computers and other devices are the buildings. If you have an individual neighborhood connected by roads, then the neighbors can all travel to each other. For the neighborhood to reach the rest of the road system, they must pay someone to build a road to connect all of their roads to it. The ISP (company) will make this connection and now the users are able to travel anywhere. Of course, since internet speeds are much faster than a road vehicle, this distance is covered in seconds (or even less).

As of 2019, there were over 20 billion devices connected to the internet, including PCs, smartphones, smart TVs, and vehicles (Help Net Security, 2019). The cabling that connects the backbone together is a mix of copper cable and fiber optic. Fiber optic is much faster but it is a newer technology, so not all geographic locations will have the option of fiber.

Under the Sea

To connect all of the continents of the earth together in this network, kilometers of cable have been laid under the oceans using special equipment. Over 99 percent of intercontinental data is transferred by these cables, which include copper and fiber optic (Main, 2015). Fiber optic cabling uses light pulses to simulate the values for 0 and 1 over long distances. Copper cabling uses electrical signals that are slower and can degrade over distances; fiber optic signals travel much more reliably.

How the Internet Works

We have explored how internet devices are connected together and examined how data is divided into packets with IP addressing for delivery, yet there is much more to the operation of the internet.


The hardware of the internet includes connecting devices such as routers, cabling, network cards, computers, smartphones, and any other physical device that connects to the internet, whether by wire or wireless.


The internet uses the TCP/IP fault-tolerant protocol to deliver data to and from every node (device) on the network. Devices using TCP/IP must have an IP address, a default gateway, and a subnet mask (called a “prefix” in IP version 6).


Computers and devices connected to the internet typically have a role of either a “client” or a “server.” A client is a device using services provided online, whereas a server is a dedicated machine that provides data services to clients. Servers are typically very powerful computers with a high-speed internet connection.

The World Wide Web

Now mostly called the “Web,” this is a special set of services that is delivered to a web browser. Basically, anything you can access in a web browser is part of the web. The web was created primarily to communicate formatted documents with pictures and hyperlinks using a simple markup language called HTML (Hyper Text Markup Language). Eventually, it evolved into what is used today including video services and websites with interactive JavaScript and connections to databases of information.

Other web services

Besides “surfing the Web,” internet users can access other data streams and services. Examples include music streaming services, online games, and direct video chat software. These internet applications do not require a browser and are therefore not part of the web.


To access these services, an IP address is required. However, users are not able to make up any address they want and must acquire a proper address from somewhere that properly identifies their network. Fortunately, this is part of the package that an ISP provides. It will automatically provide you with an IP address using a service called DHCP. This service, Dynamic Host Configuration Protocol, provides not only an IP address, but a subnet mask and default gateway as well. It also provides you with addresses for DNS servers. By default, desktops and Wi-Fi devices search the local network for a DHCP server and request configuration. Once configuration is given, the communication can begin.


Another very important internet service is the Domain Name System. As we have mentioned, every internet device requires a 32-bit IP address to transmit and receive data. Imagine if human users had to memorize and type in 32 zeroes and ones just to access a website? This would prove quite cumbersome. Fortunately, DNS is a translation service that maps names to IP addresses. When you type in or click a link to a Web address, you are accessing something called a URL, or Uniform Resource Locator. It includes the full DNS name of the computer.

A URL actually contains several pieces of information. The first part indicates the protocol used for communication. HTTP and HTTPS are both part of the TCP/IP protocol suite—they exist specifically to transfer data for a web page. The secure version uses encryption to protect private data. Many sites use encryption—you should never type in personal data on any site that is not using HTTPS (this is often indicated on a browser by a small padlock icon). Since the beginning of the Web, many people thought that you must simply type “www” to connect to a website. However, the web server could have any alphabetic name—www was simply the most common (services such as Gmail and Yahoo Mail have different server names: and The computer name identifies which computer you are communicating with on a network. The domain name, for instance,, identifies the network that the computer belongs to. When you put both of these together you get the “hostname,” such as A hostname is very important; it is what the DNS service uses to look up the correct IP address.

You can imagine DNS like a large internet phone directory—you know the computer’s name, but you want to know its number. These special servers are placed all around the world to accept lookup requests. When you want to view a website, DNS automatically goes into action. If the request takes more than an instant, many web browsers will display in the bottom status window the message: “looking up host.” Once the IP address is retrieved, your computer will remember it for a specified amount of time in the DNS cache. This means it won’t have to keep looking up the same address for sites you visit frequently.

Once you have connected to the computer you are looking for, it needs to know exactly what file you wish to open. After the computer hostname in the URL is a file folder (or multiple folders) that indicates where the file is located, followed by the filename itself. That file is retrieved and sent out over the network to your web browser to be displayed.

A file or folder location is optional in a URL; if it is not provided, the web server will provide the default file it was configured to send.

The Growing Internet

The internet is providing new services every day as they are invented. Companies now offer “cloud services” where users can store all of their documents and photos online where they can be accessed and synchronized on multiple devices. More smart devices are constantly being added to become part of the Internet of Things (IoT). New users in remote locations are being connected, enabling them to communicate all over the world. The internet has continued to grow by leaps and bounds since its creation, and it shows no signs of stopping.

The Internet of Things

At first, the devices that were connected to the internet were standard computers—they were divided into powerful servers and individual client machines. As the internet grew, the benefit was observed to connecting other types of devices to the internet: “non-standard” devices is a way to describe them. These have become the Internet of Things (IoT).

There are already over a billion of these devices connected to the internet. They include many “smart” devices. Light bulbs that can be controlled remotely are a type of smart device. Regular and self-driving vehicles are also connected to the internet. Some devices can provide feedback on their performance. A home appliance such as a smart refrigerator can tell you recipes, whether you are running low on eggs, how much power it is using, and an optimal temperature setting. Wearable technology such as smartwatches are part of the IoT as well as many medical monitoring devices. Security cameras all over the world are connected to the internet so users can access them from anywhere to see what is happening. Televisions are now smart and can access the internet for you, along with wireless speakers. People can work out in front of a smart mirror so they can watch themselves exercise while instructions and calorie counts are displayed on the screen. The mirror could also display the day’s weather or stock reports.

Uses for IoT Devices

There are many different reasons to connect a device to the internet. One of the reasons is that these devices can be programmed to function in different ways, whereas a standard device would have to be continually manually adjusted.

A good example is having an IoT home thermostat system. It can be programmed to change the temperature settings for different days of the week at different times. A maximum and minimum temperature can be added to always keep a location between two temperatures, switching between heat and cooling without you having to worry about which is running. Not only that, but with a smartphone app you can change the temperature settings for your home without even being there. The Nest thermostat will track your energy usage for you and give you monthly reports over the web. It also can learn your preferences for temperature and create a weekly schedule automatically.

IoT devices can store data and create web reports of statistics like your heat usage, but they can also retrieve data from the internet.

A smart refrigerator can keep track of what food you have and download recipes that are made of those exact ingredients. In fact, the Samsung Family Hub refrigerator can use the expiration dates on food to recommend recipes to use up those items first. Using a home network, devices can even communicate with each other—the refrigerator could recommend a recipe that, if chosen, would then send a command to the oven to preheat for cooking.

Smart devices can also customize your home experience—including setting mood lighting and playing music. Not only that, personal AI assistants such as Amazon’s Alexa and Google’s Assistant can talk to you, answer questions, and control household devices like televisions and speakers. This is possible due to average household internet speeds being fast enough to handle larger data streams. Without having to type or use a computer, you can simply talk to your home assistant and ask for light, music, information from the web, or to watch a specific sporting event on TV.

Security and IoT

Connecting billions of devices to the internet also presents a security issue. One issue is similar to a previous problem when Wi-Fi became popular. Home internet users purchased a Wi-Fi access point but never changed the default name or password; at the time, the default passwords were the same for each manufacturer. This enabled easy access to millions of home networks, basically “free internet” for anyone who took advantage of it. Eventually internet service providers started pre-programming Wi-Fi devices with complex passwords which mostly eliminated this problem.

Recently, people are buying more wireless security cameras and are doing the same thing: leaving the default passwords in place. There are millions of unsecured security cameras operating all over the world, so many that it has even created a new hobbyist community of users who randomly watch different cameras for entertainment.

Intercepting data from devices is a security risk, but more concerning is that these devices could be completely taken over without proper security measures. In the worst case it could mean that a self-driving vehicle is taken over, or a device like an oven is used to cause a fire or other property damage—including loss of life. Even simple, seemingly harmless devices can be used for nefarious purposes. Since IoT devices are given an IP address, they are able to make requests of other devices online. This means that millions of them could be compromised to make something called a botnet—an army of internet robots that can be controlled by a single user or program. Botnets are most often used in a DDoS attack—this is a distributed denial of service attack, where a server is flooded with so many simultaneous requests for data that it cannot answer them all and either stops working or becomes so slow that it is mostly unusable.

Other concerns include companies using these devices to gather data on users. These devices could learn your shopping, eating, sleeping, and movement habits. Parents are concerned that smart toys might be spying on children or, worse, trying to influence them somehow. There have been few standards set at this point for IoT devices to prevent such things.

IoT Standards

Companies like Microsoft and organizations like IEEE are working on creating standards that will help improve the function and development of IoT devices, while addressing security issues as well. One of these is the protocol 6LoWPAN. This protocol is designed for low-power IoT devices that may be very small and run on a simple

battery—normal IP communication could eat up batteries quickly, so 6LoWPAN implements compression along with other power-saving settings (Leverage, 2020).

IoT and the Future

The addition of new devices to the IoT continues every day. New types of devices to connect are being created. This means that there will be more security issues and more problems, as well as new solutions for them. It is likely that, in the near future, human beings themselves will be connected to the internet through some type of brain interface—several organizations are working on this. The U.S. Army is creating brain chips to help with PTSD (Tucker, 2014), and Elon Musk’s Neuralink is developing a brain interface to help with medical conditions that will also be able to interface with networks (Alexiou, 2020).

As more devices are added, computer programmers will find that more and more of their work is not writing applications for computers or even smartphones, but for IoT “smart” devices.


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