Computer Hardware Day4 Networks

8/12/2019 Computer Hardware Day4 Networks

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Computer Networks

Sarbjeet Prasad [email protected]


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Computer Network

A network is a group of computers connectedtogether in a way that allows information tobe exchanged between the computers.


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Computer Network contd.

A network is first and foremost a system toenable communications among multiplelocations and people.

A network also creates synergy , where thesum of the whole is potentially greater thanthe sum total of the parts.


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Why Network?

In today's business world, reliable andefficient access to information has becomean important asset in the quest to achieve acompetitive advantage.File cabinets and mountains of papers havegiven way to computers that store and

manage information electronically.


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Why Network? contd.

Coworkers thousands of miles apart canshare information instantaneously, just ashundreds of workers in a single location cansimultaneously review research datamaintained online.


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Why Network? contd.

The Internet is the most striking example ofcomputer networking, linking millions ofcomputers around the world.


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Physical Networking-the Hardware

The physical part of networking is all

hardware. Its tangible -you can hold it in yourhand. Its the wiring and network cards andcomputers and hub and all other stuff thatallows the network to function.


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Physical topology

A physical topology is simply thearrangement of a network.Kind of topologies:Bus (simplicity)Star (Reliability)

Ring (Reliability and speed)


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Bus


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Star


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Token ring


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Logical topology

Bus and star topologies are often used forEthernet networks, which are the mostpopular types of network; ring topologies are

used for Token Ring , which is less popularbut equally functionalThe main differences between Ethernet,Token Ring and FDDI (complex startopology) topologies stem from how theyallow computers to communicate with eachother.


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Logical topology contd.

Ethernet, Token Ring and FDDI are referredas logical topologies. Unlike physicaltopologies, which you can touch and pick up,logical topologies are not concerned withwires, cabling, and hardware; logicaltopologies are the rules of the road for

networks.FDDI (pronounced fid-ee) and stands for Fiber Distributed Data Interface.


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A typical network consists of:

nodes (computers)

a connecting medium (wired or wireless)specialized network equipment like routers orhubs or switch.


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Node

A node is anything that is connected to thenetwork. While a node is typically acomputer, it can also be something like aprinter or CD-ROM tower.


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Medium

Ethernet devices attach to a commonmedium that provides a path along which theelectronic signals will travel. Historically, thismedium has been coaxial copper cable , buttoday it is more commonly a twisted pair orfiber optic cabling.


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coaxial copper cable twisted pair


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Specialized network equipment

Switches (a network connection point) allowdifferent nodes , typically a computer of anetwork to communicate directly with oneanother in a smooth and efficient manner.


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Networking hardware's

Wiring and cabling are used to connectdevices.

A Hub or Switch or MAU is a device thatprovide the network with a single point ofcontact for all other devices.Router and bridges are devices that move(manages) data flow between networks.


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LAN and WAN

Local Area Network (LAN) - A LAN is anetwork of computers that are in the samegeneral physical location, usually within abuilding or a campus. If the computers are farapart (such as across town or in differentcities), then a Wide Area Network (WAN) is

typically used.


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Protocols

ProtocolsIn networking, the term protocol refers to aset of rules that govern communications.Protocols are to computers what language isto humans. Since this slide is in English, tounderstand it you must be able to read

English. Similarly, for two devices on anetwork to successfully communicate, theymust both understand the same protocols.


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The Ethernet rule (CSMA/CD)

The acronym CSMA/CD signifies carrier-sense multiple access with collisiondetection and describes how the Ethernetprotocol regulates communication amongnodes.


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Carrier sense

Carrier sense: Before a station transmits, it"listens" to the medium to determine ifanother station is transmitting. If the mediumis quiet, the station recognizes that this is anappropriate time to transmit.


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Multiple access

The term multiple access means when oneEthernet station transmits, all the stations onthe medium hear the transmission.


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Collision detection

Collision-in terms of networking, the thing thathappens when two computers attempt totransmit data on the same network wire at thesame time . This create a conflict; bothcomputers sense the collision, stoptransmitting , and wait a random amount of

time before retransmitting.


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Networking Hardwares


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Physical Network

Network Interface Card (NIC) - Everycomputer (and most other devices) isconnected to a network through an NIC. Inmost desktop computers, this is an Ethernetcard (normally 10 or 100 Mbps) that isplugged into a slot on the computer's

motherboard.


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Add-in NIC Card


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Build-in (integrated) NIC card


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Patch panel Patch cord

RJ-45 Jack


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Switch or hub


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Bandwidth

A term used to describe the maximum speedat which a given device (such as a networkcard or modem) can transfer data.Bandwidth is measured in kilobits per secondor megabits per second.


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Internet

The Internet is a network of networks.

The Internet is a series of private computernetworks connected to each other.


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Intranet

Typically, if you build a LAN or WAN-that is, aprivate network-using Internet standards, youhave created an internal Internet, or Intranet.


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Extranet

If you connect your intranet to the Internetand make provisions for your customers andbusiness partners to use pieces of yourintranet to do business with you, youve gonea step beyond an intranet and created anextranet.


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The OSI reference modelTCP/IP addressing

Identifying different component of a LAN


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IPX

Internetworking Packet Exchange (IPX).Designed by Novell

On the whole, IPX is easy to install andsimple to use.Not an open standard


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NetBIOS and NetBEUI

Network Basic Input/Output System(NetBIOS) and NetBIOS Extended UserInterface (NetBEUI) are single-site networkprotocols.


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Summary

A protocol is a set of rules for sending andreceiving data across a network.Logical topologies instruct the hardware howto packetize and transmit data across thephysical topology.


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Summary contd.

Protocols handle the translation of data fromapplication to the logical topology.

TCP/IP, IPX, NetBIOS/NetBEUI

Ethernet, Token Ring, FDDI, ATM

Bus, Star, Ring Physical topology

Logical topology

Protocol

Documents

Computer Hardware Day4 Networks