computer networks workshop
DESCRIPTION
Introduction to Computer Networks, Types, Devices, Companies, Vendors and jobsTRANSCRIPT
ENG224
INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Who R We?? دماغهم شباب فدماغك بتجيىف اللى نفساألفكار
االجازه فى
Why We do that ? ... .. اكتب.. .. فيديو اشرح شير ترجم ... أعلن
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Index:
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Computer Networks :• Group of interconnected computers
• First Network : The Advanced Research Projects Agency (ARPA) funded the design of the "Advanced Research Projects Agency Network" (ARPANET) for the United States Department of Defense
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Importance of Networks:
• Sharing information • Do you prefer these?
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• Or this?
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
• Sharing hardware or software
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• E.g. print document
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• Centralize administration and support• E.g. Internet-based, so everyone can access the same
administrative or support application from their PCs
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5.5. Network Types… Network Types…Size…Management…TopologySize…Management…Topology
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Network Classification : 1
• By Size or Scale– LAN– WAN– MAN– CAN– PAN
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Local Area Network (LAN)
• Contains printers, servers and computers• Contained in one office or building• Organizations often have several LANS• Small network, short distance
• Limited by no. of computers and distance covered• Serve a department within an organization
• Examples: • Network inside the Student Computer Room• Network inside your home
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• Wide Area Network (WAN)• Two or more LANs connected Over a large
geographic area• Typically use public, leased lines phone lines
• Examples:• Internet
WAN
Student Computer Centre
Your home
USA
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• Example WAN technologies:
• ISDN – Integrated Service Digital Network• Basic rate: 192 Kbps Primary rate: 1.544Mbps
• ATM – Asynchronous Transfer Mode• Support B-ISDN: 155Mbps or 622Mbps or higher
Large network that connects different organizations
Shares regional resources
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Metropolitan Area Network (MAN)
A LAN in one large geographic area
Resources related to the same organization
Each department shares the LAN
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Campus Area Networks (CAN)
Very small scale network
Range is less than 2 meters
Cell phones, connectify :D
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Personal Area Network (PAN)
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Network Classification : 2
• By Structure / Functional / Management Relationship :
1- Peer to Peer. 2- Client / Server.
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Peer-to-Peer Networks• Peer-to-peer network is also called workgroup• No hierarchy among computers all are equal• No administrator responsible for the network
Peer-to-peer
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• Advantages of peer-to-peer networks:• Low cost• Simple to configure• User has full accessibility of the computer
• Disadvantages of peer-to-peer networks:• May have duplication in resources• Difficult to uphold security policy• Difficult to handle uneven loading
• Where peer-to-peer network is appropriate:• 10 or less users• No specialized services required• Security is not an issue• Only limited growth in the foreseeable future
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Clients and Servers• Network ClientsClients (WorkstationWorkstation)
• Computers that request network resources or services
• Network ServersServers• Computers that manage and provide network resources and
services to clients • Access to data controlled by server• Server is the most important computer
• Usually have more processing power, memory and hard disk space than clients
• Run Network Operating System that can manage not only data, but also users, groups, security, and applications on the network
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• Advantages of client/server networks• Facilitate resource sharing – centrally administrate and
control• Facilitate system backup and improve fault tolerance• Enhance security – only administrator can have access
to Server• Support more users – difficult to achieve with peer-to-
peer networks
• Disadvantages of client/server networks• High cost for Servers• Need expert to configure the network• Introduce a single point of failure to the system
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Network Classification : 3
By Topology / Physical Connectivity
– BUS– STAR– RING– MESH– TREE
Network Topology– Logical layout of wires
and equipment– Choice affects
Network performance Network size Network collision detection
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Topology ― 3 basic types• How so many computers are connected together?
Bus Topology Ring Topology
Star Topology
Hub
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• Bus Topology (Linear) • Simple and low-cost الدش توصيلة• A single cable called a trunk (backbone, segment)
connects all nodes• Only one computer can send messages at a time• Terminator ends the wires
Advantages
Easy to setupSmall amount of wire
DisadvantagesSlowEasy to crash
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Star Topology: (Centralized Device)Most common topology• Each computer has a cable
connected to a single point• More cabling, hence higher cost• All signals transmission through the hub; if down, entire network down• All nodes connect to a hub….Packets sent to hub…Hub sends packet to destination
Advantages :
Easy to setup
One cable can not crash network
Disadvantages
One hub crashing downs entire network
Uses lots of cable
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How to construct a network with Bus / Star Topology?
Star Topology
Bus Topology
BNC T-Connector
Coaxial cable
Network Card
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• Ring Topology :( الخارجيه (مبنى• Every computer serves as
a repeater to boost signals• Typical way to send data:
• Token passing• only the computer who
gets the token can send
data• Disadvantages
• Difficult to add computers• More expensive• If one computer fails, whole network fails
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
MESH
• All computers connected together
• Internet is a mesh network
• Advantage– Data will always be
delivered• Disadvantages
– Lots of cable– Hard to setup
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
TREE
• Hierarchal Model
• Advantages– Scalable– Easy Implementation– Easy Troubleshooting
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Traaaaaaaaacks
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Vendors :
• http://www.cisco.com/• http://www.nortel-us.com/• http://www.avaya.com/usa/• http://www.juniper.net/• http://www8.hp.com/us/en/home.html
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• Links that connect nodes with certain Speed, Security, and Size
• Two main categories:– Guided ― wires, cables– Unguided ― wireless transmission, e.g. radio,
microwave, infrared, sound, sonar
• We will concentrate on guided media first:– Twisted-Pair cables:
Unshielded Twisted-Pair (UTP) cables Shielded Twisted-Pair (STP) cables
– Coaxial cables– Fiber-optic cables
Transmission Media
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• If the pair of wires are not twisted, electromagnetic noises from, e.g., motors, will affect the closer wire more than the further one, thereby causing errors.
• Most common LAN cable• Called Cat5 or 100BaseT• Four pairs of copper cable twisted• May be shielded from interference• Speeds range from
1 Mbps to 1,000 Mbps
Twisted-Pair Cables
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Unshielded Twisted-Pair (UTP)
• Typically wrapped inside a plastic cover (for mechanical protection)
• A sample UTP cable with 5 unshielded twisted pairs of wires
MetalInsulator
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Shielded Twisted-Pair (STP)• STP cables are similar to UTP cables, except there
is a metal foil or braided-metal-mesh cover that encases each pair of insulated wires
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Coaxial Cables• In general, coaxial cables, or coax,• Similar to cable TV wire• One wire runs through cable• Shielded from interference• Speeds up to 10 Mbps
• Outer metallic wrapping serves both as a shield against noise and as the second conductor that completes the circuit
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Fiber-Optic Cables
• Data is transmitted with light pulses• Glass strand instead of cable• Immune to interference• Very secure• Hard to work with• Speeds up to
100 Gbps
• Beyond the critical angle total internal reflection
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Advantages and Disadvantages Noise resistance ― external light is blocked by outer
jacket Less signal attenuation ― a signal can run for miles
without regeneration (currently, the lowest measured loss is about ~4% or 0.16dB per km)
Higher bandwidth ― currently, limits on data rates come from the signal generation/reception technology, not the fiber itself
Cost ― Optical fibers are expensive Installation/maintenance
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Wireless Media:
• Data transmitted through the air• LANs use radio waves• WANs use microwave signals• Easy to setup• Difficult to secure• Examples: Wi-Fi
Wi-MAX VSAT
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Communication Model
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Communication Model
• Source– generates data to be transmitted
• Transmitter– Converts data into transmittable signals
• Media– Carries data
• Receiver– Converts received signal into data
• Destination– Takes incoming data
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Transmission Modes
• Simplex– One direction
e.g. Television
• Half duplex– Either direction, but
only one way at a time e.g. police radio
• Full duplex– Both directions at the
same time e.g. telephone
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
Communication Types
• Unicasting (one-to-one)
• Multicasting (one-to-many)
• Broadcasting (one-to-all)
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
How to Start in IT ???
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؟ .. وفقط العمل المشور نهاية هل• والخبره للتعلم بدايه ده أصال تشتغل انك مجرد
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INFORMATION TECHNOLOGY – Part II5. Introduction to Networking
• /Unified and Integration Inside
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