Introduction Computer Networking(1)

8/3/2019 Introduction Computer Networking(1)

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Introduction to

Networks

Networking Concepts

IST-200

VWCC

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What is Networking?

Connecting computers

to form a

Local Area Network

( LAN )

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Device Sharing

Sharing of:

HardwareSoftware

Information

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A Simple Network

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Local & Wide Area

NetworksEarly networks were custom builtConnecting a dozen computers

Only 1 or 2 peripherals

Early Ethernet

30 users total span of 601 feet

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Local Area Network

(LAN)A single collection of machines &peripherals

Generally less than 1000 computers

Spanned generally less than 250meters feet

Basic building block for largernetworks-Internetworks

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InterNetworks

IntraNetworksA network of networks

A networked collection of LANsMore than one floor in abusiness (intranetwork)

Multiple buildingsCampus environment

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Wide Area Networks

(WAN)Spans miles of distance

Two or more separate locationsDown the road or across the

world

Microsoft, Federal Express

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The Internet

A WAN internetwork

Millions of machines worldwide

The World Wide Web (WWW)

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Networking

TerminologyClient/Server relationship

Client requests sharedresources

Server responds & shares

resources

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Networking

Terminology

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Client Server

NetworksConcentrate CPU power & storage

capacityWindows NT Server / Server 2000

Peer to Peer

Client/Server role interchanges

Windows 95/98/2000/XP

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Simple Network Needs

Medium to carry data

Adapter (NIC)

Protocol

Client / Server Software


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Local Network

Medium (media)Carries network messages

Connects machines together onnetwork

Four types: Metallic cable coaxial - dated

Twisted pair

Fiber optic cable

Wireless

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Network Interface

Card(NIC)

Physical link between machine& network

Connection between machine &

medium

Also known as network adapter

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Network Protocols

Common set of communication rules

Identify oneself & others on network

Interpret signals

Begin & end network communication

Manage network information exchange

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Protocol Examples

TCP/IP

for the Internet

IPX/SPX & NWLINK

for Novell

NetBEUI for Microsoft

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Network Software

Programs that access the network

Network Operating System (NOS)

Windows NT

Novell NetWare (IntranetWare)

Consist of client & servercomponents

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Network LayersNetwork Applications ( NOS &client)

Instruct network mediumUsing machines interface (NIC)

Address & exchange information

To other machines on LAN or WAN

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Layers of the

Network

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Network TypesPeer to Peer

Windows 98/2000

Windows for WorkgroupsClient Server (server-based)

Windows NT

NovellUnix / Linux

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Peer to PeerNo centralized controlAct as both client & server

User controls access to machine

Institutionalized chaos & securityconcerns

Adding machines slows networkdown

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Peer to Peer

DisadvantagesSecurity for only a single resourceat a time

Users may need to know manypasswords

Individual machine backups

Speed decreases while sharingNo central location/access of data

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Server Based

NetworksServer is the key to this type

Centralized control of resourcesUtilize faster processors

More memory

Extra peripherals

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Server Security

Physical access to the server

Specialized sentry servers

Domain model

Account names

PasswordsFirewalls

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Server Based

AdvantagesCentral security/ accounts/ access

Simplify network administration

Powerful/ efficient access to

resources

Single password for each userBest for high use, user, networks

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Server Based

DisadvantagesServer failure results in unusable network

Server failure results in loss of resourcesExpert staff to manage increases cost

Dedicated hardware increases cost

Dedicated software increases cost

All disadvantages may be overcome

with $$$

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Server Hardware

Requirements

High Speed DrivesMirrored or

RAID

512 MB Memory Minimum

High Quality NIC(s)

High-end Processor(s)

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Specialized Servers

Individual services supplied

Application Servers

Communication Servers

Domain Controllers/Directory

ServersFax Servers

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Specialized Servers

(cont.)Mail Servers

Web ServersFile & Print Servers

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Communication

ServersAccess beyond networks local scope

Inbound & outbound resource access

Dial in via modem

Windows NT server Remote Access

Server(RAS) manages dial in networkconnections

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Domain Controllers/

Directory ServersLocate, store, & secure informationabout network

Allows computers, users, groups, &resources to be combined intodomains

Domain access allows single loginto all allowed resources

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File and Print Servers

File storage & File retrieval

Access to network printersApplications run locally

Store data on server

Window NT server is capable

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Web Servers

World Wide Web (WWW)

File Transfer Protocol (FTP)

Gopher services

Intranets

NT Server Internet InformationServer (IIS)

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Selecting the Right

NetworkBudget considerations, number ofusers?

Physical span of the network?

Specialized servers, services desired?

Internetwork or WAN access?Future growth?

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Summary

Basic elements to build a network

Medium, physical interface, protocol

Networking software-client & server

Basic network types

Peer to PeerServer based

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Introduction Computer Networking(1)

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