Computer Fundamentals : Networking

Major components of a computer network are:

1. NIC(National interface card):

A network interface card (NIC) is a device that allows a computer to communicate with another device. The hardware addresses are stored on the network interface card, and the data-link layer protocol uses them to identify the system on the network and send data to the correct location.

There are two types of NIC: wireless NIC and wired NIC

• Wireless NIC: All modern laptops use wireless NIC. In Wireless NIC, a connection is made using the antenna that employs radio wave technology.
• Wired NIC: Cables use the wired NIC to transfer the data over the medium.

1. Hub

A hub is a central device that divides a network connection among several devices. When a computer asks another computer for information, it transmits the request to the Hub. This request is distributed to all linked computers by the hub.

1. Switches

A switch is a networking device that connects all of the devices on a network so that data can be sent from one to the other. A switch is superior to a hub because it sends the message to the device to which it belongs rather than broadcasting it over the network. As a result, the message is sent directly from the source to the destination by the switch.

1. Cables and connectors

A cable is a transmission media that transmits the communication signals. 

There are three types of cables:

• Twisted pair cable: It is a high-speed cable that transmits the data over 1Gbps or more.
• Coaxial cable: Coaxial cable resembles a TV installation cable. Coaxial cable is more expensive than twisted-pair cable, but it provides a high data transmission speed.
• Fibre optic cable: Fibre optic cable is a high-speed data transmission wire that uses light beams to transport data. When compared to other cables, it provides a high data transmission speed. Because it is more expensive than other cables, it is only installed at the government level.

1. Router

A router is a device that links your local area network (LAN) to the internet. The router is mostly used to connect different networks or to connect several computers to the internet.

1. Modem

A modem is a device that connects a computer to the internet using an existing phone line. A modem is not built into the motherboard of a computer. A modem is a separate component that plugs into a PC slot on the motherboard.

1. Uses Of Computer Network

• Resource sharing: Resource sharing is the sharing of resources like programs, printers, and data across network users without regard for the resource's or user's geographical location.
• Server-Client model: The server-client model takes advantage of computer networking. A server is a computer that is used to store data and is managed by the system administrator. Clients are the machines that connect to the server remotely to access data.
• Communication medium: A computer network serves as a means of communication between users. For example, a corporation with multiple computers may have an email system that employees utilize on a daily basis.
• E-commerce: Computer network is also important in businesses. We can do business over the internet. For example, amazon.com is doing their business over the internet, i.e., they are doing their business over the internet.

1. Communication speed

We can communicate quickly and efficiently over the network thanks to the network. We can do video conferencing, email messaging, and other things over the internet, for example. As a result, the computer network provides an excellent means of exchanging information and ideas.

1. File sharing

One of the most significant advantages of a computer network is the ability to share files. The computer network allows us to share files with one another.

1. Back up and Rollback is easy

Because the files are stored on a centrally situated core server. As a result, taking a backup from the primary server is simple.

1. Software and Hardware sharing

We can install the applications on the main server, allowing users to access them from anywhere. As a result, we won't have to install software on every computer. Hardware can be shared in the same way.

1. Security

The network allows security by ensuring that the user has the right to access certain files and applications.

1. Scalability

Scalability refers to the ability to add new components to the network. The network must be scalable, allowing us to expand it by adding more devices. However, it reduces the connection speed and the data transmission pace, which raises the odds of an error occurring. The use of routing or switching devices can solve this difficulty.

1. Reliability

In the event of a hardware breakdown, a computer network can use an alternative source for data communication.

A computer network is a collection of computers that are linked together so that one computer can communicate with another and share resources, data, and applications.

The size of a computer network can be classified.

There are four primary types of computer networks:

• LAN(Local Area Network)
• PAN(Personal Area Network)
• MAN(Metropolitan Area Network)
• WAN(Wide Area Network)

LAN(Local Area Network)

• Local Area Network is a group of computers connected to each other in a small area such as a building, office.
• LAN is used for connecting two or more personal computers through a communication medium such as twisted pair, coaxial cable, etc.
• It is less costly as it is built with inexpensive hardware such as hubs, network adapters, and ethernet cables.
• The data is transferred at an extremely faster rate in Local Area Network.
• Local Area Network provides higher security.

PAN(Personal Area Network)

• Personal Area Network is a network arranged within an individual person, typically within a range of 10 meters.
• Personal Area Network is used for connecting the computer devices of personal use is known as Personal Area Network.
• Personal Area Network covers an area of 30 feet.
• Personal computer devices that are used to develop the personal area network are the laptop, mobile phones, media player, and play stations.

There are two types of Personal Area Networks:

Computer Network Types

1. Wired Personal Area Network
2. Wireless Personal Area Network
3. Wireless Personal Area Network: Wireless Personal Area Network is developed by simply using wireless technologies such as WiFi, Bluetooth. It is a low-range network.

 Wired Personal Area Network: Wired Personal Area Network is created by using the USB.

MAN(Metropolitan Area Network)

• A metropolitan area network is a network that covers a larger geographic area by interconnecting a different LAN to form a larger network.
• Government agencies use MAN to connect to the citizens and private industries.
• In MAN, various LANs are connected to each other through a telephone exchange line.
• The most widely used protocols in MAN are RS-232, Frame Relay, ATM, ISDN, OC-3, ADSL, etc.
• It has a higher range than Local Area Network(LAN).

Uses Of Metropolitan Area Network:

• MAN is used in communication between the banks in a city.
• It can be used in an Airline Reservation.
• It can be used in a college within a city.
• It can also be used for communication in the military.

 WAN(Wide Area Network)

• A Wide Area Network is a network that extends over a large geographical area such as states or countries.
• A Wide Area Network is quite a bigger network than a LAN.
• A Wide Area Network is not limited to a single location, but it spans over a large geographical area through a telephone line, fiber optic cable, or satellite links.
• The internet is one of the biggest WANs in the world.
• A Wide Area Network is widely used in the field of Business, government, and education.

Topology

A Network Topology is the arrangement with which computer systems or network devices are connected to each other. Topologies may define both physical and logical aspects of the network. Both logical and physical topologies could be the same or different in the same network.
There are five types of topology in computer networks:

1. BUS

2. Ring

3. Tree

4. Star

5. MESH

6. HYBRID

1. Mesh Topology-
   In mesh topology, each device is connected to every other device on the network through a dedicated point-to-point link. When we say dedicated it means that the link only carries data for the two connected devices only. Let's say we have n devices in the network then each device must be connected with (n-1) devices of the network. A number of links in a mesh topology of n devices would be n(n-1)/2. 

1. Star Topology

All hosts in Star topology are connected to a central device, known as hub device, using a point-to-point connection. That is, there exists a point-to-point connection between hosts and hub. The hub device can be any of the following:

• A layer-1 device such as hub or repeater.
• A layer-2 device such as switch or bridge.
• A layer-3 device such as router or gateway.

3. BUS topology-

In a bus topology, there is the main cable, and all the devices are connected to this main cable through drop lines. There is a device called a tap that connects the drop line to the main cable. Since all the data is transmitted over the main cable, there is a limit of drop lines and the distance the main cable can have.

4.Ring Topology-

In-ring topology each device is connected with the two devices on either side of it. There are two dedicated point-to-point links a device has with the devices on either side of it. This structure forms a ring thus it is known as a ring topology. If a device wants to send data to another device then it sends the data in one direction, each device in ring topology has a repeater, if the received data is intended for another device then the repeater forwards this data until the intended device receives it.

4. Hybrid topology-

A combination of two or more topologies is known as hybrid topology. For example, a combination of star and mesh topology is known as hybrid topology.

 OSI or Open System Interconnection model was developed by International Standards Organization (ISO). It gives a layered networking framework that conceptualizes how communications should be done between heterogeneous systems. It has seven interconnected layers. The seven layers of the OSI Model are a physical layer, data link layer, network layer, transport layer, session layer, presentation layer, and application layer, as shown in the following diagram −

The physical layer, data link layer, and network layer are the network support layers. The layers manage a physical transfer of data from one device to another. The session layer, presentation layer, and application layer are the user support layers. These layers allow communication among unrelated software in dissimilar environments. The transport layer links the two groups.

The main functions of each of the layers are as follows −

• Physical Layer − Its function is to transmit individual bits from one node to another over a physical medium.
• Data Link Layer − It is responsible for the reliable transfer of data frames from one node to another connected by the physical layer.
• Network Layer − It manages the delivery of individual data packets from source to destination through appropriate addressing and routing.
• Transport Layer −It is responsible for the delivery of the entire message from the source host to the destination host.
• Session Layer − It establishes sessions between users and offers services like dialog control and synchronization.
• Presentation Layer − It monitors the syntax and semantics of transmitted information through translation, compression, and encryption.
• Application Layer − It provides high-level APIs (application program interface) to the users.