COMPUTER NETWORKING. By: Dr. Noor Dayana Abd Halim

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1 COMPUTER NETWORKING By: Dr. Noor Dayana Abd Halim

2 Defining Computer Network Computer network is a collection of computers and other hardware devices so that network users can share hardware, software, data and they can communicate with each other electronically.

Defining Computer Network Computer networking is connecting a computer with other computers or other devices to enable them to communicate with each other,

3 Defining Computer Network Computer networking is connecting a computer with other computers or other devices to enable them to communicate with each other, between computer devices/equipments transmission media to send/control data/signals communication devices to transmit/send data from sources to destinations softwares

4 Type of Network Many types of network depending on the geographical area.

5 Type of Network

6 Type of Network : Local Area Network, LAN Covers relatively small geographical area. Eg. Home, schools, office building Client/ server network is example of LAN Allows file exchange, s, printer sharing or accessing the internet

7 Type of Network : Metropolitan Area Network, MAN Network designed to service a metropolitan area, a city or a county Owned or provided by a city or network provider For local people s access to internet Example in Malaysia? 3 network of LAN for Mid Valley City

Type of Network : Wide Area Network, WAN network that covers large / broad geographical area Ex: telecommunications network that links across metropolitan, regional, or national boundaries) using

8 Type of Network : Wide Area Network, WAN network that covers large / broad geographical area Ex: telecommunications network that links across metropolitan, regional, or national boundaries) using private or public network transports. In essence, this mode of telecommunication allows a business to effectively carry out its daily function regardless of location. Internet: world s largest WAN

9 Type of Network : Wide Area Network, WAN

10 Network Component What you need to set up a network? 1. Hots / End Nodes 2. Transmission Media 3. Network Electronics Devices 4. Software / Application 5 Network Architecture Standards & Protocols

11 Network Component : 1. Hots /End Nodes Refers to the data source and the data destination. Examples: Personal computers Terminals Workstations Automatic Teller Machine

12 Network Component : 2. Transmission Media For transmitting data and control signals Responsible for sending electric or signal through spesific media. It can be bounded (wired) or unbounded (wireless) media

13 Network Component : 3. Network Electronic Device Responsible to control data from source to destination Provide interface between different media transmitter or for different protocol To connect multiple network together or to connect computer or network to the internet Examples: Bridges Routers Multiplexers Switches Hubs Gateways Front End Processors

14 Network Component : 3. Network Electronic Device

15 Network Component : 4. Applications/ Software The applications at the end nodes (what is end node?) normally involves technique and protocols The protocol determines the rules and procedure to send data, terminate data, interpret data, present data and control mistakes Software in the network functions to ensure data is delivered at respective destination to control data transmission

16 Network Component : 5. Network Architecture Standard & Protocol NAS: The blueprint of standards that define: How device in a network typically connect How the device can communicate To ensure interoperability between various devices and equipment made by different vendors. To enable devices made by different companies to work or communicate with each other.

17 Network Component : 5. Network Architecture Standard & Protocol Example : TCP/IP, Ethernet (802.3), Wi-Fi (802.11), WiMAX etc

18 Networking Architecture Network architecture is the way they are design to communicate 2 types : 1. Client/Server Networks 2. Peer to Peer Networks

19 Networking Architecture : 1. Client/Server Networks 1) Client/ server: Client = computers that request or utilize network resources Server = processing the request by client What is network server? Provide access to software, files etc being shared in the network Retrieves file from server: download Transfer from client to server : upload

20 Networking Architecture : 2. Peer to Peer Networks 2) Peer to peer No central server Have direct access to other devices attached to the network As long as they are declared as shared devices Internet peer to peer: eg. itunes, Bluetooth between handphone

21 Network Topology Network topology is the study of the arrangement or mapping of the elements (links, nodes, etc.) of a network, especially the physical (real) and logical (virtual) interconnections between nodes How the hardware/ devices are placed and arranged 2 types 1. Physical 2. Logical

22 Network Topology: 1. Physical 1. Physical topology : The physical layout of devices on a network. or the way that the devices on a network are arranged and how they communicate with each other The way that the workstations are connected to the network through the actual cables that transmit data 5 Types : 1. Linear Bus 2. Ring / Star-wired 3. Star 4. Tree / Hybrid 5. Mesh

23 Physical Network Topology: 1. Linear Bus 1. Linear Bus consists of central cable to which all devices are connected with a terminator at each end. ƒ All nodes (file server, workstations, and peripherals) are connected to the linear cable. Data transmitted through the bus line from one device to the other. Network cannot function when the bus line fails. Ethernet and LocalTalk networks use a linear bus topology. The message is transmitted along the cable and is visible to all computers connected to that cable.

24 Physical Network Topology: 1. Linear Bus

25 Physical Network Topology: 2. Ring 2. Ring Each of the systems is connected to its respective neighbor forming a ring. Sometimes called star-wired network The main difference between the bus and ring is that the ring topology does not require termination. Because the systems are connected all together in a loop, there is no beginning and end point as there is with the bus topology. No terminator and no bounce back signal.

26 Physical Network Topology: 2. Ring

27 Physical Network Topology: 3. Star 3. Star All networked devices are connected directly to the central device (hub) / concentrator From central device, all network transmissions are sent Data on a star network passes through the hub or concentrator before continuing to it destination. The hub or concentrator manages and controls all functions of the network. It also acts as a repeater for the data flow.

28 Physical Network Topology: 3. Star

29 Physical Network Topology: 4. Tree / Hybrid 4. A tree (hybrid) Can incorporate structures such as ring, star and bus network in one large network It consists of groups of star-configured workstations connected to a linear bus backbone cable. Allow for the expansion of an existing network, and enable schools to configure a network to meet their needs.

30 Physical Network Topology: 4. Tree / Hybrid

31 Physical Network Topology: 5. Mesh 5. Mesh Computers have redundant physical connections to one another When the mesh network is a WAN (such as the Internet), or a LAN that is divided into multiple subnets, routers make decisions about which of the multiple available paths will be taken. Decide based on which one is the most effective

32 Network Topology: 2. Logical 2. Logical topology : how the systems communicate across the physical topologies the way that the signals act on the network media, or the way that the data passes through the network from one device to the next without regard to the physical interconnection of the devices. 2 types: 1. shared media topology 2. token-based topology

33 Logical Network Topology: 1. Shared Media 1. Shared media In a shared media topology, all the systems have the ability to access the physical layout whenever they need it. Advantage : the systems have unrestricted access to the physical media. Disadvantage : Collisions - If two systems send information out on the wire at the same time, the packets collide and kill both packets. If add more systems to the network, there is a greater opportunity for collisions. To help reduce the number of collisions, many networks are broken up into several smaller networks with the use of switches or hubs, and each network is then referred to as its own collision Example: Ethernet

34 Logical Network Topology: 2. Token Based 2. Token-Based Have a token that travels around the network. When a system needs to send out packets, it grabs the token off of the wire, attaches it to the packets that are sent, and sends it back out on the wire. As the token travels around the network, each system examines the token. When the packets arrive at the destination systems, those systems copy the information off of the wire and the token continues its journey until it gets back to the sender. When the sender receives the token back, it pulls the token off of the wire and sends out a new empty token to be used by the next machine.

35 Logical Network Topology: 2. Token Based Advantage : Do not have the same collision problems that Ethernet-based networks do because of the need to have possession of the token to communicate. Disadvantage : Latency Because each machine has to wait until it can use the token, there is often a delay in when communications actually occur. Token-based network are typically configured in physical ring topology because the token needs to be delivered back to the originating machine for it to release. The ring topology best facilitates this requirement.

36 Thank You!

Dr./ Ahmed Mohamed Rabie Sayed

1 Dr./ Ahmed Mohamed Rabie Sayed 2 A network is a group of two or more computer systems linked together to exchange data and share resources, including expensive peripherals. 3 A local area network (LAN)