Computer networking is the practice of connecting multiple computers and devices to enable communication and the sharing of resources. It involves the design, implementation, management, and maintenance of both hardware and software components that allow different devices to exchange data and collaborate. And it plays a vital role in the exam of IBPS RRB CLERK / PO 2023.
Computer networks can be classified into different types based on their size, geographical scope, and purpose.
Computer Networking Types
- Local Area Network (LAN): A LAN connects devices within a limited area such as a home, office building, or campus. It enables the sharing of resources like files, printers, and internet access among connected devices.
- Wide Area Network (WAN): A WAN spans across larger geographical areas, connecting multiple LANs or other networks. The internet itself can be considered as the largest example of a WAN. WANs use routers, switches, and other networking devices to facilitate long-distance communication.
- Metropolitan Area Network (MAN): A MAN covers a larger area than a LAN but is smaller than a WAN. It connects multiple LANs within a city or metropolitan region, providing high-speed connectivity.
- Wireless Network: Wireless networks use radio waves or infrared signals instead of physical cables to connect devices. Wi-Fi networks are a common example of wireless networks, allowing devices to connect to the internet without the need for physical connections.
- Virtual Private Network (VPN): A VPN creates a secure, encrypted connection over a public network (like the internet) to allow remote users to access a private network securely. It is often used for remote work, enabling users to access resources on a private network while connected from outside the physical location.
Computer networking relies on various protocols and standards to establish communication between devices. The most important protocol suite is the TCP/IP (Transmission Control Protocol/Internet Protocol), which forms the backbone of the Internet. Other protocols like Ethernet, Wi-Fi, and DNS (Domain Name System) are also crucial components of computer networking.
Network topology refers to the physical or logical arrangement of devices and connections in a computer network. It defines how nodes (computers, servers, routers, switches, etc.) are connected and how data flows within the network. Different network topologies are used depending on the requirements of the network in terms of scalability, fault tolerance, performance, and cost.
Types of network topology
- Bus Topology: In a bus topology, all devices are connected to a common backbone or a single communication line. Each device receives all the data transmitted on the bus, but only the intended recipient processes the data. It is a simple topology but can be prone to a single point of failure if the backbone fails.
- Star Topology: In a star topology, each device is connected to a central hub or switch. All communication is routed through the central hub, which acts as a central point of control. If one device fails, it does not affect the rest of the network, and it allows easy scalability by adding or removing devices.
- Ring Topology: In a ring topology, devices are connected in a closed loop, where each device is connected to exactly two other devices. Data travels in one direction around the ring until it reaches the intended recipient. It requires less cabling compared to other topologies, but if one device or connection fails, it can disrupt the entire network.
- Mesh Topology: In a mesh topology, every device is connected to every other device in the network. It provides multiple redundant paths for data transmission, enhancing fault tolerance and network reliability. Mesh topologies can be full mesh (direct connection between all devices) or partial mesh (only selected devices are directly connected).
- Tree Topology: A tree topology, also known as a hierarchical topology, is a combination of bus and star topologies. Devices are arranged in a hierarchical structure, where lower-level devices are connected to higher-level devices until they reach a root node. It provides scalability and allows for the easy addition of devices, but the failure of the root node can affect the entire network.
- Hybrid Topology: A hybrid topology combines two or more different topologies. For example, a network might have a combination of star and mesh topologies, or a mix of wired and wireless connections. Hybrid topologies are often used to meet specific network requirements and to optimize performance and reliability.
The OSI (Open Systems Interconnection) model is a conceptual framework that standardizes the functions of a communication system or network into seven different layers. It was developed by the International Organization for Standardization (ISO) in the late 1970s to facilitate interoperability between different vendors’ networking technologies.
Layers of OSI (Bottom to Top)
- Physical Layer: The physical layer deals with the transmission of raw bit streams over physical media, such as copper cables, fiber optics, or wireless connections. It defines the electrical, mechanical, and procedural aspects of data transmission.
- Data Link Layer: The data link layer provides reliable transmission of data frames between adjacent nodes over the physical layer. It handles error detection, flow control, and framing. Ethernet and Wi-Fi are examples of data link layer protocols.
- Network Layer: The network layer is responsible for the logical addressing and routing of data packets between different networks. It determines the optimal path for data transmission, handles addressing, and deals with congestion control. IP (Internet Protocol) is a key protocol of the network layer.
- Transport Layer: The transport layer ensures reliable and error-free end-to-end data delivery between hosts. It segments the data from the upper layers into smaller units, provides flow control, and manages reliable delivery mechanisms. TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) operate at this layer.
- Session Layer: The session layer establishes, manages, and terminates communication sessions between applications. It provides services for session establishment, synchronization, and checkpointing. It manages session security and can include protocols such as SSL (Secure Sockets Layer) or TLS (Transport Layer Security).
- Presentation Layer: The presentation layer is responsible for data representation, encryption, compression, and conversion between different data formats. It ensures that data sent by the application layer is in a format that can be understood by the receiving party.
- Application Layer: The application layer is the closest layer to the end user. It provides services directly to user applications and supports network applications like email, file transfer, and web browsing. Protocols such as HTTP (Hypertext Transfer Protocol), FTP (File Transfer Protocol), and SMTP (Simple Mail Transfer Protocol) operate at this layer.
TCP/IP Protocol Suite
The TCP/IP (Transmission Control Protocol/Internet Protocol) protocol suite is a collection of networking protocols that are widely used for communication and data exchange on the Internet and many private networks. It serves as the foundation for modern Internet communication and provides a set of standardized rules and procedures for transmitting data between devices.
The TCP/IP protocol suite consists of several protocols, each responsible for specific functions within the overall communication process. Here are some of the key protocols in the TCP/IP suite:
- Internet Protocol (IP): IP is responsible for the addressing and routing of data packets across networks. It assigns unique IP addresses to devices and ensures that data is sent to the correct destination. IPv4 (Internet Protocol version 4) and IPv6 (Internet Protocol version 6) are the two main versions of IP.
- Transmission Control Protocol (TCP): TCP is a reliable, connection-oriented protocol that operates at the transport layer. It provides error detection, flow control, and congestion control to ensure reliable data delivery. TCP breaks data into packets, manages their sequencing, and reassembles them at the destination.
- User Datagram Protocol (UDP): UDP is a simpler, connectionless protocol also operating at the transport layer. It is less reliable than TCP but is often used for applications that require fast and lightweight communication, such as streaming media or real-time communication.
- Internet Control Message Protocol (ICMP): ICMP is used for diagnostics and reporting errors in IP network communications. It allows devices to send error messages or query information about network conditions.
- Address Resolution Protocol (ARP): ARP is used to resolve IP addresses to physical MAC (Media Access Control) addresses on a local network. It helps devices identify the physical hardware addresses of other devices.
- Internet Group Management Protocol (IGMP): IGMP is used for managing IP multicast group membership. It allows hosts to join or leave multicast groups and receive multicast data streams.
- Domain Name System (DNS): DNS is responsible for translating human-readable domain names (e.g., www.example.com) into IP addresses. It acts as a distributed directory service for mapping domain names to corresponding IP addresses.
Internet vs Intranet
The terms “Internet” and “intranet” refer to different types of computer networks.
The Internet is a global network of interconnected computers and networks that allows for communication, information sharing, and access to various services. It is a massive public network accessible to anyone with an Internet connection. The Internet uses the TCP/IP protocol suite and is decentralized, meaning it does not have a central governing authority.
Key features of the Internet:
- Wide availability: It is accessible to individuals, businesses, and organizations worldwide.
- Public network: It is open to everyone and facilitates global communication and information exchange.
- Use of standard protocols: The Internet relies on protocols like HTTP, FTP, SMTP, and DNS for various services.
- Huge collection of resources: It provides access to websites, email services, search engines, online applications, and more.
- Connection of networks: It connects numerous networks across the globe, enabling data transmission and routing.
An intranet is a private network that functions similarly to the Internet but is accessible only to authorized users within a specific organization or company. It utilizes the same technologies and protocols as the Internet, such as TCP/IP, web browsers, and email, but restricts access to internal users.
Key features of an intranet:
- Restricted access: Only authorized users within an organization can access the intranet.
- Enhanced security: Intranets often have security measures in place, such as firewalls and authentication mechanisms, to protect sensitive data.
- Internal resources and services: It provides access to internal websites, shared files, databases, collaboration tools, and company-specific applications.
- Efficient communication: Intranets facilitate internal communication through email, instant messaging, discussion forums, and video conferencing.
- Customization: Organizations can tailor the design and content of their intranet to suit their specific needs and requirements.
|Publicly accessible to anyone
|Limited to authorized users within an organization
|Generally less secure due to its openness
|Enhanced security measures for internal data protection
|Global network connecting countless networks
|Limited to a specific organization or company
|Public websites, online services, vast information
|Internal resources, company-specific applications
|Decentralized, no central governing authority
|Owned and managed by the organization
|Connects various networks worldwide
|Connects internal departments and branches
|Enables access to external resources
|Restricted access to internal resources
|Facilitates global communication and collaboration
|Enhances internal communication and collaboration
|World Wide Web, email, online services
|Corporate intranet, employee portals, shared files
Some Important Questions
Which of the following devices operates at the Data Link layer of the OSI model?
Which protocol is used for translating domain names into IP addresses?
What is the default subnet mask for a Class C IP address?
Which transport layer protocol guarantees the reliable delivery of packets?
Which type of network topology connects all devices in a closed loop?
What is the maximum data rate of a Gigabit Ethernet connection?
a) 100 Mbps
b) 1 Gbps
c) 10 Gbps
d) 100 Gbps
Which of the following IP addresses is a valid public IP address?
Which protocol is used for secure communication over the Internet?
Which network device acts as an intermediary between a local network and the Internet?
What is the maximum length of an Ethernet cable in a standard wired network?
a) 50 meters
b) 100 meters
c) 150 meters
d) 200 meters
b) 1 Gbps
b) 100 meters