basic networking and topologies explained.ppt
- 1. INTRODUCTION NETWORKING By Lahiru Ratnayake MBA ,BSc, DNIIT, IPICT, Dip. in Networking
- 2. WHAT IS A NETWORK? • A network is simply two or more computers that are linked together. • In short, networks, which consist of computers connected together so that they can communicate, enhance both business and personal productivity by enabling users to share resources. • Computer networks allow users to share data and hardware. They also allow people from all over the world to communicate and collaborate in a variety of ways.
- 4. TYPES OF NETWORKS • The most common types of networks are: • Personal Area Networks (PAN) • Local Area Networks (LANS) • Metropolitan area network (MAN) • Wide Area Networks (WANS).
- 5. Personal Area Networks (PAN) • A personal area network (PAN) is a computer network used for communication among computer devices, including telephones and personal digital assistants, in proximity to an individual's body. • The devices may or may not belong to the person in question. The reach of a PAN is typically a few meters. • PANs can be used for communication among the personal devices themselves (intrapersonal communication), or for connecting to a higher level network and the Internet (an uplink). • Personal area networks may be wired with computer buses such as USB and FireWire. • A wireless personal area network (WPAN) can also be made possible with wireless network technologies such as IrDA, Bluetooth, Wireless USB, Z-Wave and ZigBee.
- 7. LOCAL AREA NETWORK • Local Area Network (LAN) – a network that spans a small area such as a building or an office. – Software applications and other resources are stored on a file server. – Print servers enable multiple users to share the same printer. • Local Area Network (LAN) A local area network (LAN) is a collection of devices connected together in one physical location, such as a building, office, or home. – A LAN can be small or large, ranging from a home network with one user to an enterprise network with thousands of users and devices in an office or school.
- 9. Metropolitan area network(MAN) • A Metropolitan Area Network (MAN) is a network that is utilized across multiple buildings • Commonly used in school campuses or large companies with multiple buildings • Is larger than a LAN, but smaller than a WAN • Is also used to mean the interconnection of several LANs by bridging them together. This sort of network is also referred to as a campus network
- 11. Storage Area Network(SAN) • A SAN (Storage Area Network) is a network designed to transfer data from servers to targets, and it is alternative to a directly attached target architecture, where the storage is connected to the servers on general purpose networks • Additional definitions of a SAN imply that the SAN should also be highly performing, and should be such to enable storage devices to communicate with one another and with computer systems
- 13. Wide Area Network(WAN). • Wide Area Network (WAN) – a network that spans a wide geographical area; there are several types of WANS – Campus Area Network(CAN) - a network spanning multiple LANs but smaller than a MAN, such as on a university or local business campus. – Storage Area Network(SAN) - connects servers to data storage devices through a technology like Fibre Channel. – Metropolitan Area Network(MAN)- a network spanning a physical area larger than a LAN but smaller than a WAN, such as a city. A MAN is typically owned an operated by a single entity such as a government body or large corporation.
- 15. Wireless LAN • A wireless local area network(LAN) is a flexible data communications system implemented as an extension to, or as an alternative for, a wired LAN. – Using radio frequency (RF) technology, wireless LANs transmit and receive data over the air, minimizing the need for wired connections. • Thus, combining data connectivity with user mobility.
- 17. TYPES OF NETWORK (cont) • Intranet – An intranet is a private LAN designed for use by everyone within an organization. An intranet might consist of an internal e-mail system, a message board and one or more Web site portals that contain company news, forms, and personnel information. Access to an intranet’s web site is restricted by a firewall. • Extranet – a network that connects people within your company with people who are outside your company--all within a secure, password-protected network that can be accessed from anywhere.
- 18. BENEFITS OF A NETWORK (Advantage) • Usage of Network –Information sharing: Authorized users can use other computers on the network to access and share information and data. This could include special group projects, databases, etc. –Hardware sharing: One device connected to a network, such as a printer or scanner, can be shared by many users. –Software sharing: Instead of purchasing and installing a software program on each computer, it can be installed on the server. All of the users can then access the program from a single location. –Collaborative environment: Users can work together on group projects by combining the power and capabilities of diverse equipment.
- 19. BENEFITS OF A NETWORK (Advantage) – Enhancement of Communication and Information Availability: ... – Convenient Sharing of Resources: ... – Easy File/Data Sharing: ... – Highly Flexible: ... – Affordable: ... – Increases Cost Efficiency: ... – Networking Boosts Storage Capacity: ... – Enhanced Security and Data Protection:
- 20. RISKS OF NETWORK COMPUTING(Disadvantage) • The security of a computer network is challenged everyday by: – Equipment malfunctions – System failures • Note: equipment malfunctions and system failures may be caused by natural disasters such as floods, storms, or fires, and electrical disturbances – Computer hackers – Virus attacks
- 21. Network Terms • Client is a piece of computer hardware or software that accesses a service made available by a server, in which case the client accesses the service by way of a network. The term applies to programs or devices that are part of a client–server model. • Server is a computer that stores and provides resources, data, and services to the network.
- 23. HOW ARE NETWORKS CATEGORIZED? • Networks are usually classified using three properties: • Topology • Protocol • Architecture
- 24. NETWORK/COMMUNICATION PROTOCOLS • A protocol is simply an agreed-on set of rules and procedures for transmitting data between two or more devices. • Features determined by the protocol are: – How the sending device indicates it has finished sending the message. – How the receiving device indicates it has received the message. – The type of error checking to be used.
- 25. NETWORK/COMMUNICATIONS PROTOCOLS • Most networks use Ethernet, but some network may use IBM’s Token Ring protocol. • On the Internet, the major protocol is TCP/IP (an acronym for Transmission Control Protocol/Internet Protocol).
- 26. COMMUNICATION PROTOCOLS File transfer protocol (FTP) – used to transmit files. Simple mail transfer protocol (SMTP) – used to transmit e-mail messages. Post office protocol (POP) – allows the recipient to retrieve messages. Wireless application protocol – enables wireless devices to access and use the Internet using a client/server network. 802.11 – protocol for wireless LAN technology
- 27. NETWORK COMMUNICATIONS SOFTWARE • E-Mail Software – used to send and receive electronic messages using the Internet • Web Browser – allows users to access and view Web pages • Groupware – allows groups of people on a network to share information and to collaborate on various projects
- 28. Network Service • A networking service is a low- or high-level application that enables the network to perform more than basic functions. Some examples of networking services include NTP, DNS, DHCP, VoIP, File and Directory, Hardware Sharing, Email, and Website Hosting.
- 29. NETWORK ARCHITECTURE • Network architecture – refers to the way a network is designed and built. The two major types are: – Peer-to-peer architecture – Computers connect with each other in a workgroup to share files, printers, and Internet access. This is used to connect a small number of computers. – Client/server architecture – sends information from a client computer to a server, which then relays the information back to the client computer, or to other computers on the network
- 31. Peer-to-Peer Network (con) • A peer-to-peer network is decentralised, self-organising, highly scalable and each node has equal privileges and responsibilities. • A peer-to-peer (P2P) network is a type of decentralised network architecture where each node, or 'peer', has the same capabilities and responsibilities.
- 32. Client/Server Network • A client-server network is a computing model in which multiple clients connect to a central server to access resources, such as files, applications, and data. • The server acts as a central hub, managing and providing services to the connected clients.
- 34. Advantages of Client/Server • Centralization – The fundamental benefit of a client-server network is that it allows for centralized management—all the information you can find in one place. Because the network administrator has complete control over management and administration. • Adaptability – Customers can easily expand the number of clients or servers. Because the server is centralized, there are no concerns regarding authorization to network resources growing in size. The setups only require a small number of people. • Protection – Because of the centralized design of a client-server network, data is adequately secured. So only if you’re an authorized user can you access the data via login and password and two-factor authentication. In addition, if the data is lost, the records can be recoverable quickly with one backup. • Operation – It is simple to handle files because they are all kept on a single server. A client-server network can simply monitor and access necessary file records.
- 35. Disadvantage of Client/Server • Overloading – Every time when too many clients request access simultaneously, there is a risk of collapse or deceleration of your connection. So there is always a small chance not to reach necessary information. • Cost – The servers are expensive. You can’t put a normal SSD in there, just like a home computer. Why? Because hardware for servers has quite different reliability requirements, and there is support for specific functions. – It can be a significant problem for smaller businesses that may not have the resources to maintain a server and client infrastructure.
- 36. Examples of client-server architecture • Web-servers – Provide access to web applications and content such as HTML files, images, or other resources. These servers are responsible for handling requests, rendering pages, and serving content to users. • Application server – Designed to centrally solve application tasks in some subject area. To do this, users have the right to run server programs. Using application servers reduces client configuration requirements and simplifies overall network management. • Database server – Database servers are used to process user requests in SQL. The DBMS is located on the server to which client applications are connected. • File servers – The file server stores the information as files and provides users access. As a rule, a file server provides a certain protection against unauthorized access. • Proxy server – First, it acts as an intermediary, helping users to access Internet information while protecting the network. Second, it stores frequently requested information in a cache on a local drive, delivering it quickly to users without having to re access the Internet. • Firewalls (Firewalls) – Provide the ability to monitor and control incoming and outgoing network traffic. Utilizing various rules and settings, it can be used to block unwanted connections, detect malicious data packets, and protect from potential security threats. • Mail servers – Provide users with the ability to send and receive emails. The server handles authentication, storage, and delivery of emails.