Computer Networks PCCST501 Semester 5 KTU CS 2024 Scheme - Dr Binu V P

  Introduction to Computer Networks What is a Computer Network? A computer network is a collection of interconnected devices that can communicate and share data with each other. These devices may include: Desktop computers Laptops Smartphones Servers Printers Routers Switches The connection between devices can be established using: Wired media → cables such as Ethernet or fiber optics Wireless media → Wi-Fi, Bluetooth, cellular communication, etc. Simple Definition A computer network is the interconnection of devices capable of exchanging information. Why Do We Need Computer Networks? Computer networks are used to: Share Resources Printers Files Internet connection Enable Communication Email Video conferencing Messaging Share Data Databases Cloud storage Multimedia content Improve Reliability and Efficiency Backup systems Distributed processing Example of a Small Network When two computers at home a...

  Introduction to the Internet What is the Internet? An internet (with lowercase i ) refers to two or more interconnected networks that can communicate with each other. The most famous and largest internetwork is the Internet (with uppercase I ). Definition The Internet is a global system of interconnected networks that allows communication and resource sharing among millions of users worldwide. Structure of the Internet The Internet consists of three main parts: Backbone Networks Provider Networks Customer Networks 1. Backbone Networks Backbones are: Large high-speed networks Owned by major communication companies Examples: AT&T Verizon Sprint NTT These networks form the core of the Internet. Peering Points Backbone networks are interconnected through complex switching systems called: Peering Points These allow backbone networks to exchange data with one another. 2. Provider Networks Provider networks: Connect to backbo...

  Comparison Between Circuit Switching and Packet Switching Feature Circuit Switching Packet Switching Communication Type           Continuous           Packet-based Path           Dedicated path           Shared path Resource Usage           Reserved for entire session           Used only when transmitting Efficiency           Less efficient           More efficient Delay           Minimal after setup           Possible queuing delay Storage in Switches           No           Yes Best Suited For           Voice calls           Computer networks and Internet

  Switched Network Introduction A switched network is a network in which a device called a switch connects two or more communication links together. The switch receives data from one link and forwards it to another link whenever needed. Definition A switched network is a communication network in which switches are used to forward data from one link to another. Role of a Switch A switch performs the task of: Receiving data Determining the destination Forwarding the data to the correct link In modern communication systems, switching helps multiple users communicate efficiently. Types of Switched Networks There are two main types of switched networks: Circuit-Switched Network Packet-Switched Network 1. Circuit-Switched Network Introduction In a circuit-switched network , a dedicated communication path called a circuit is established between two end systems before communication begins. The path remains reserved during the entire communication sess...

Introduction to Internetwork What is an Internetwork? An Internetwork (or internet ) is formed when two or more networks are connected together to allow communication between them. These networks may be: LANs WANs Or a combination of both Definition An internetwork is a collection of interconnected networks that communicate with one another as a single system. Why is Internetworking Needed? Today, networks rarely exist in isolation. Organizations often have: Multiple offices Different departments Networks in different locations To enable communication between all these networks, they are interconnected to form an internetwork. Example of an Internetwork Consider a company with: One office on the east coast Another office on the west coast Each office has its own LAN. To allow communication between employees in different offices: The company leases a WAN connection from a service provider The WAN connects the two LANs Now both networks bec...

  Comparison Between LAN and WAN Feature LAN (Local Area Network) WAN (Wide Area Network) Full Form Local Area Network Wide Area Network Geographical Coverage Covers a small area such as a room, office, building, or campus Covers a large area such as a city, country, or the world Ownership Usually privately owned by an individual or organization Usually owned and managed by communication companies or service providers Purpose Connects devices within a limited area Connects multiple LANs and networks over long distances Devices Connected Mainly connects hosts such as computers, printers, and servers Mainly connects networking devices such as routers, switches, and modems Communication Speed Generally high speed Usually slower compared to LAN Transmission Media Ethernet cables, Wi-Fi Fiber optics, leased lines, satellite links, telephone lines Cost Lower installation and maintenance cost Higher installation and maintenance cost Data Transfer Delay Very low delay Higher delay due to ...