Networking involves connecting electronic devices like computers to share resources and communicate. It allows devices to share internet access, hardware like printers, files and folders, and play multiplayer games. Networks use various topologies like star, bus or mesh to connect devices via physical cables or wireless links, and network protocols allow the connected devices to communicate according to shared rules.

2. WHAT IS NETWORKING? Networking involves connecting computers and other electronic devices for the purpose of sharing information and resources and for communication.

3. Network Categories Local Area Network (LAN) Metropolitan Area Network (MAN) Wide Area Network (WAN)

4. What we can do by using networking? Share a single internet connection

5. What we can do by using networking? Share a printer, scanner and other hardware

6. What we can do by using networking? Share files and folders

7. What we can do by using networking? Play multi-computer games

8. CLIENTS, PEERS, AND SERVERS Server Client Peer Computer that share resources across the network. Responds from client by providing the requested information or denying the request. Computer that accesses shared resources. Request information from server. Computer that act as a server and at the same time can be client.

9. NETWORK MEDIUM To communicate successfully, computers must share access to a common network medium. Network medium:- Physical Cable (twisted –pair, coaxial, fiber optic) Wireless To carry the signals one computer send to one or more other computers. To access any network, computer must attach to network medium by using physical interface (NIC, network adapter)

10. NETWORK PROTOCOL When connected to a network, a computer must also be able to use that connection. They must share a common set of rules to communicate. This rules must include how to interpret signals, how to identify “oneself” and other computers on a network, how to initiate and end networked communication.

11. NETWORK SOFTWARE Computers need network software to issue the requests and responses that let them take the roles of clients and servers. Computers that participate on a network run a network operating system (NOS) that determines what services that computer can offer or request. NOS also controls access to the network service and network resources. Example of NOS: - Windows Server 2003, Red Hat Linux, Windows NT.

12. NETWORK LAYOUT- TOPOLOGY Network topology refers to physical layout of the computers, cables, resources and how those components communicate with each other.

13. BUS TOPOLOGY All components connect via a backbone . Signal are bounce. No longer a practical choice.

14. RING TOPOLOGY Connect directly to next computer in line, ending at the starting computer. Signal travel in only one direction around the rings.

15. STAR TOPOLOGY Computers connected by cable segments to a central devices. Doesn't specify how signals should travel from computer to computer

16. WIRELESS TOPOLOGY Eliminate the need for a visible physical topology. Two computers can communicate directly with one another in an ad hoc topology (peer to peer technology) Wireless LAN – use a central device called an access point.

17. MESH TOPOLOGY Most fault tolerance but also the most expensive. Connecting each device in a network to every device in the network.

18. A SIMPLE NETWORK LAYOUT DIAGRAM

19. OVERVIEW OF OSI LAYER NETWORK MODEL What is layered model? Models help us to visualize different aspects of complex abstract systems Almost all communication can be broken down into independent layers that work interdependently. The ‘layers' (and protocols between them) conceptually represent negotiations between aspects of communication: Content, logical (encoding) and physical delivery of messages.

20. WHAT IS LAYERED MODEL?

21. WHAT IS A LAYERED MODEL? OSI 7-Layer Model International Standards Organization’s Open Systems Interconnection model TCP/IP Model Developed by the Department of Defense 2 models for network communications

22. THE OSI LAYERED MODEL OSI – Open System Interconnection Layered Approach Allows better interoperability between software and hardware Allows design of elaborate but highly reliable protocol stacks

23. OSI LAYERS - WHAT DOES EACH LAYER DO? The Physical Layer Defines all electrical and physical specifications for devices. Major Functions Establishment & Termination of Connections Connection Resolution & Flow Control of Communication Resources Modulation & Conversion between Digital Data Example – radio, SCSI (Small Computer System Interface)

24. OSI LAYERS - WHAT DOES EACH LAYER DO? The Data Link Layer Controls data transfer between network entities Performs error detection & correction Uses physical/flat Addressing Scheme Example - Ethernet

25. OSI LAYERS - WHAT DOES EACH LAYER DO? The Network Layer Performs network routing, flow control, segmentation, and error control functions The router operates at this layer Uses local addressing scheme Example – IP, token ring

26. OSI LAYERS - WHAT DOES EACH LAYER DO? The Transport Layer Provide transparent transfer of data between end users Controls reliability of a given link Some protocols are stateful and connection oriented (cookies) Example – TCP / UDP

27. OSI LAYERS - WHAT DOES EACH LAYER DO? The Session Layer Provides mechanism for managing the dialogue between end-user application processes Provides for either duplex or half-duplex operation Responsible for setting up and tearing down TCP/IP sessions Example – NetBIOS

28. OSI LAYERS - WHAT DOES EACH LAYER DO? The Presentation Layer Little to do with PowerPoint Controls syntactical differences in data representation within end-user systems MIME encoding is done at this layer Example - XML

29. OSI LAYERS - WHAT DOES EACH LAYER DO? The Application Layer Provide semantic conversion between associated application processes Interfaces directly to and performs common application services for the application processes Example – Telnet, Virtual Terminal

30. TCP/IP LAYERED NETWORK MODEL Transmission Control Protocol and Internet Protocol TCP/IP is a suite of protocols, also known as the Internet Protocol Suite It was originally developed for the US Department of Defense Advanced Research Project Agency (DARPA) network, but it is now the basis for the Internet Application Transport Internet Network access

31. TCP/IP NETWORK MODEL LAYERS

32. TCP/IP LAYERS - WHAT DOES EACH LAYER DO? As with the OSI model, the TCP/IP suite uses a layered model. TCP/IP model has four or five - depending on who you talk to and which books you read! Some people call it a four layer suite - Application , Transport , Internet and Network Access , others split the Network Access layer into its Physical and Datalink components. Application Transport Internet Network access

33. TCP/IP LAYERS - WHAT DOES EACH LAYER DO? The combination of datalink and physical layers deals with pure hardware (wires, satellite links, network interface cards, etc.) Access methods such as CSMA/CD (carrier sensed multiple access with collision detection) Ethernet exists at the network access layer - its hardware operates at the physical layer and its medium access control method (CSMA/CD) operates at the datalink layer. Application Transport Internet Network access

34. This layer is responsible for the routing and delivery of data across networks. It allows communication across networks of the same and different types and carries out translations to deal with dissimilar data addressing schemes. IP (Internet Protocol) and ARP (Address Resolution Protocol) are both to be found at the Internet layer. TCP/IP LAYERS - WHAT DOES EACH LAYER DO? Application Transport Internet Network access

35. The transport layer is similar to the OSI transport model, but with elements of the OSI session layer functionality. The two protocols found at the transport layer are: TCP (Transmission Control Protocol): reliable, connection-oriented protocol that provides error checking and flow control through a virtual link that it establishes and finally terminates. Examples include FTP and Email UDP (User Datagram Protocol): unreliable, connectionless protocol that not error check or offer any flow control. Examples include SNMP TCP/IP LAYERS - WHAT DOES EACH LAYER DO? Application Transport Internet Network access

36. This layer is broadly equivalent to the application, presentation and session layers of the OSI model. It gives an application access to the communication environment. Examples: Telnet HTTP (Hyper Text Transfer Protocol) SMTP (Simple Mail Transfer Protocol) TCP/IP LAYERS - WHAT DOES EACH LAYER DO? Application Transport Internet Network access