What is Networking?
Networks are things that are connected, to put it simply. They are all around us and come in many different forms like
- Friend and social groups
- Transportation links within a city
- Power supply girds
- Your neighborhood
and many other examples, wherever something is connected/linked to others, it's likely to be a network.
In computing, networking is all about the connection of technological devices and how they are linked together so that you can communicate and share things with others.
There are three main components in networks:
- Nodes : Individual devices that are connected to the network
- Links : Communication pathways that link the nodes together(wired/wireless)
- Data Sharing : The main use case of the network is to enable data exchange
In a real-world example, a group of office workers talking to each other form the network, each worker is a node and then talking to each other are the links. What they are talking about is the data being shared across these links and to the various workers.
Why is it important?
Networks are significant as they enable us to do a range of things, especially now that we have the Internet. It helps us share physical and software resources, communicate with others via instant messaging, emails, and video calls, access files and databases from any connected device, and collaborate with others to work together in real-time when they are physically far apart.
Types of Networks
There are two main types of networks, Local Area Network(LAN) and Wide Area Network(WAN).
Local Area Network
They connect devices over a small area and these types of networks are controlled by one person or body. Due to not having much scale, the data transfer rate is higher and uses Ethernet cables for wired connection or Wi-Fi for wireless.
Example of an LAN
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| Internet |
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|
|
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| Modem |
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|
|
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| Router |
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|
|
------------- ------------ ----------
|Smartphone |---| PC | ------- | Laptop |
------------- ------------ ----------
| | |
| | |
----------- | |
| Printer | -------| ----------
----------- | Tablet |
----------
There can be a mix of wired and wireless connections, for example, the PC and printer have a wired connection whilst the smartphone and printer have a wireless one.
Wide Area Network(WAN)
WANs cover a larger area than LANs and are typically owned by multiple people/organizations. One example is the Internet, which is also the largest WAN there is. WANs tend to span across cities, countries and/or continents. Due to their sheer size, there are slower data transfer rates than LANs as they have to cover a longer distance. They utilize fiber optics, satellite links, and leased telecommunication lines in order to get data across.
How do they work together?
Multiple LANs can connect to WANs in order to grant expanded communication and resource sharing. An example of this is when large businesses connect many LANs to a WAN in order to achieve unified connection across geographical locations.
Home Networks, which are LANs, connect to their Internet Service Provider's (ISP's) WAN in order to gain acess to Internet. In this setup, a device called a modem (modulator-demodulator) acts as a bridge between your home network and the ISP's infrastructure, converting digital signals from your router into a format suitable for transmission over various media like telephone lines, cable systems, and fiber optics.
Identifing Devices
Humans use their name and fingerprint for verification/their identity. In a similar manner, computers have an IP Adress and MAC Adress, the IP Adress is like your name, something that can change whilst the MAC Adress is like your fingerprint, something that you cannot.
Internet Protocol Adress
An IP address is a set of numbers that are divided into four octets. The value of each octet will summarise to be the IP address of the device on the network. This number is calculated through a technique known as IP addressing & subnetting. IP addresses can change from device to device but cannot be active simultaneously more than once within the same network.
IP Addresses follow a set of standards known as protocols. These protocols are the backbone of networking and force many devices to communicate in the same language. Devices can be on both a private and public network. Depending on where they are will determine wether they have a public or private IP address.
A public address is used to identify the device on the Internet, whereas a private address is used to identify a device amongst other devices(eg. in a LAN).
Octet 1 2 3 4
IP Adress 192.168.1.1
The number in each octet is between 0 and 255.
Examples of private network IP Adress -
192.168.1.77
192.168.1.84
192.168.3.93
The first two octets stay the same for most home networks whilst the last two change.
Examples of public network IP Adress -
86.157.52.21
86.157.52.95
As more devices get connected, it has become harder to find an IP address that has not already been taken up. Cisco, an industry giant in the world of networking, estimated that there would be approximately 50 billion devices connected on the Internet by the end of 2021.
The mentioned version of the IP addressing scheme is known as IPv4 which uses a numbering system of 2^32 IP addresses (4.29 billion), not enough to meet demand.
So, in order to solve this, IPv6 was thought of which supports up to 2^128 of IP addresses (340 trillion-plus), resolving the issues faced with IP and it also uses better and improved methodologies.
IPv6 Example - 2001:0db8:85a3:0000:0000:8a2e:0370:7334
It uses the hexadecimal system which ranges from 0-9 and A-F. It is known as a base sixteen numbering system used in computing to represent numbers. IPV6 consists of 8 octets.
Media Access Control Adress
Devices on a network will all have a physical network interface, which is a microchip board found on the device's motherboard. This network interface is assigned a unique address at the factory it was built at, called a MAC address. The MAC address is a twelve-character hexadecimal number split into two's and separated by a colon. The first six characters represent the company that made the network interface, and the last six is a unique number.
eg. a4:c3:f0:85:ac:2d
MAC addresses can be faked or "spoofed" in a process known as spoofing. This occurs when a networked device pretends to identify as another using its MAC address. When this happens, it can often break poorly implemented security designs that assume that devices talking on a network are trustworthy.
Eg. A firewall is configured to allow any communication going to and from the MAC address of the administrator. If a device were to pretend or "spoof" this MAC address, the firewall would now think that it is receiving communication from the administrator when it isn't in reality.
