What is networking?

Networking is a method of linking two or more devices in order to share data, give technical support, and communicate. It refers to the communication between connected computing devices such as desktops, laptops, smartphones, servers, and tablets and also Internet of Things (IoT) devices such as cameras, doorbells, door locks, and various sensors.

The internet is a technology that allows different computer systems to communicate with one another that is located in different geographic locations. Networking technology has transformed the world and opened up a new field for each country's overall development.

There are various parameters involved when two systems communicate across the network.

Hardware: It is also known as network equipment or computer networking devices. These are electronic devices that allow devices on a computer network to communicate and interact with one another.

Firmware: Firmware is the software that is built into a piece of hardware. It is used to provide specific functionalities in hardware.

Software: It aids network administrators in the deployment, management, and monitoring of a network. These are the applications used by the end-user to interact with the network.

Security: Your network and data are protected by network security against breaches, intrusions, and other dangers. It is a set of rules and configurations that use both software and hardware to safeguard the integrity, confidentiality, and accessibility of computer networks and data.

Routing: The process of picking a path for traffic within a network, or between or across many networks, is known as routing.

Topology: Small networks are connected to each other to make a large network.

Transmission technology: The transmission technology is used for wired or wireless media to transmit information.

The networking model

A network model is typically made up of layers. Each layer of a model reflects a distinct set of capabilities. Protocols are frequently set within the layers of a model to carry out certain tasks. A protocol can be thought of as a set of rules or a language. As a result, a layer is typically made up of multiple protocols.

There are two networking models that are mostly used for communication are the OSI model and the TCP/IP model. Let us understand the OSI model-

OSI model

The OSI model stands for Open System Interconnection Model. The OSI Model is a conceptual framework in the networking model. It is an open system standard for establishing connections between the systems. The computation in the OSI Model is done through seven different layers. These layers are shown in the figure below.

The International Organization for Standardization (ISO) published the OSI Model in 1984 to describe the network architecture. The purpose of the OSI Model is to guide the developers so that the software programs and digital communication products created by the developers can interoperate to promote a clear framework that describes the functions of a networking or telecommunications system that is in use.

Physical layer

The physical layer is the lower layer of the OSI Model. It deals with electrical, mechanical, functional, and procedural characteristics of physical links. The network topology belongs to this layer. Encoding is used for data security in this layer. It is transmitted as unstructured data bits across the network from the physical layer of the sender to the physical layer of the receiver. It uses physical resources such as a hub, repeater, cables, network adapters, or modems.

Data link layer

The data link layer (DLL) is used for flow control, error control, access control, framing, and reading of physical addresses. This layer is directly connected with nodes and performs node-to-node data transfer when data is packaged into the frame. It corrects errors occurring in the physical layer. The data link layer comprises two layers Media Access Control (MAC) and Logical Link Control (LLC). MAC provides multiplexing for data transmission over the network while LLC provides error control over the physical medium.

Network layer

The network layer is the third layer of the OSI Model. It receives frames from the data link layer and delivers them to the destination. It uses address assignment, routing, and fragmentation for data transmission. In address assignment, the IP address is assigned to the host. Routing is used to select the route either manually or automatically. The network layer finds the destination using a logical address (IP address).

Transport layer

The transport layer is used to manage reliability, flow-control, congestion control, multiplexing, and demultiplexing. The transport layer manages the delivery of data packets. It is used to transfer data between system and host. RDP, RUDP, TCP, DCCP, and UDP are some of the other transport layer protocols.

Session layer

The session layer enables people on various machines to communicate with one another in real time. It's in charge of creating, maintaining, synchronizing, and terminating sessions between end-user programs. It includes authentication and reconnections.

Presentation layer

The presentation layer's major objective is to handle the syntax and semantics of information transferred between two communicating systems. The presentation layer ensures that the data is provided in such a way that the receiver understands and can utilize the information (data). It acts as the network's data translator.

Application layer

The Application Layer is the topmost layer. This layer includes numerous methods for modifying data (information), allowing any sort of user to easily access the network. The Application Layer interacts with the application directly and provides common web application capabilities.

TCP/IP Model

The full form of the TCP/IP model is Transmission Control Protocol/Internet Protocol. TCP/IP Stack is a model that is specifically developed to provide highly reliable and end-to-end byte streams over an unreliable network.

TCP/IP is a layered server architecture system, with each layer defined with a specific function to fulfill. The layers of the TCP/IP model are mentioned below.

1. Process/Application Layer
2. Host-to-Host/Transport Layer
3. Internet Layer
4. Network Access/Link Layer

1. Network Access Layer

This layer is the OSI model's combination of the Data Link Layer and the Physical Layer. It looks for hardware addressing, and the protocols in this layer enable data to be physically transmitted.

2. Internet Layer

The functions of this layer are similar to those of the OSI Network layer. It specifies the protocols that are in charge of logical data transfer across the whole network. The following are the key protocols found at this layer: IP(internet protocol), ICMP(Internet Control Message Protocol), and ARP(Address Resolution Protocol).

3. Host-to-Host layer

This layer is similar to the OSI model's Transport layer. It is in charge of end-to-end communication and error-free data transfer. It protects upper-layer applications from data complexity. The following are the two main protocols found in this layer, Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).

4. Application Layer

This layer fulfills the functions of the OSI model's top three layers: Application, Presentation, and Session. It's in charge of node-to-node communication and user interface requirements. HTTP, HTTPS, FTP, TFTP, Telnet, SSH, SMTP, SNMP, NTP, DNS, DHCP, NFS, X Window, and LPD are some of the protocols found in this layer.

Common Mistakes

The concept of routing sounds complicated but it is a simple concept. Most TCP/IP networks are set up with a gateway, which is either a specific piece of networking equipment or a computer with two or more network connections. That is what the name "router" refers to. The actual meaning of the term "internet" is also the linking of different networks.

Context and Applications

This topic is significant in the professional exams for both graduate and postgraduate courses, especially for:

• Bachelor of Technology in Computer science
• Bachelor of Technology in Information Technology
• Master of Technology in Computer network

Related Topics

• TCP/IP Model
• Wireless data networks

Practice Problems

Q1) How many layers are present in the OSI model

1. One
2. Three
3. Seven
4. Six

Correct answer- option 3. Seven

Explanation: The OSI model contains 7 layers as mentioned above.

Q2) Multiplexing and demultiplexing are handled by

1. Application layer
2. Network layer
3. Transport layer
4. None

Correct answer- option 3. Transport layer

Explanation: The transport layer collects data chunks from various sockets and encapsulates them with transport headers. Multiplexing is the process of passing these generated segments to the network layer. Demultiplexing refers to the method by which the transport layer delivers data to the correct socket.

Q3) OSI stands for

1. Open System Interchange
2. Open System Interconnection
3. Open Source Interface
4. Open System Interference

Correct answer- Option 2. Open System Interconnection

Q4) Which of the following layer does the OSI model has but the TCP/IP model does not

1. Session layer
2. Transport layer
3. Network layer
4. Application layer

Correct answer- Option 1. Session layer

Explanation: TCP/IP does not have a session layer. Instead, inside the TCP/IP model, session and presentation services are handled at the application layer.

Q5) OSI model was developed in

1. 1956
2. 1976
3. 1966
4. 1984

Correct answer- Option 4. 1984

Explanation: Since its introduction in 1984, the Open Systems Interconnection (OSI) reference model has served as the most fundamental part of computer networking. The OSI Reference Model is based on an International Standards Organization(ISO) proposal.