"Networking 101: Basics""Networking 101: Basics"

Jim Gogan

INLS184

Introduction - Why network?Introduction - Why network?

Communicate with others close by Communicate with others far away Gain access to information not on your

computer Share resources (software, peripherals)

*ANS?*ANS?

LANs WANs MANs internets Internet Intranet

Components of a LANComponents of a LAN

Cable Workstations/Servers Interface cards (NICs) Hubs/switches/etc. Peripherals Network protocols

CableCable

Types of Cables– Coaxial cable– Twisted pair– Fiber optics

Wireless

Cabling Topologies Cabling Topologies

Daisy Chain Bus Ring Star

Daisy Chain Daisy Chain

Simplest to do One device hooked to device after it If broken, all connections are lost Daisy Chain network example: original

LocalTalk

BusBus

Packets move along a straight line Works like a trolley, must have bumpers at

ends of lines Devices are connected through taps on the

line As long as taps aren’t disconnected, network

stays up Bus network example: Thin-net Ethernet

RingRing

Cable must form complete, unbroken ring Packets with presence of token (usually) If ring broken, all devices may go down Ring network example: Token Ring

StarStar

Devices are connected along “arms” of the star

Arms connected to central hub When disconnected, only that arm of the

star is affected Star network example: 10BaseT Ethernet

WorkstationsWorkstations

The computer on an individual’s desk May have its own local devices/peripherals

as well as access to networked peripherals

ServersServers

Workstation (often higher end) with specific functions

Usually provides services:– File services– Web services– Email services

Interface cardsInterface cards

Connect individual devices to network Must match type of device and type of

cable

Hubs and Switches and Hubs and Switches and Network DevicesNetwork Devices

Depends on type of network installed More about these later …...

PeripheralsPeripherals

Accessory devices (printers, fax machines, backup devices, etc.)

Originally connected thru workstations or servers, now directly network connected

Originally dumb, now intelligent enough to do some real damage

ProtocolsProtocols

Common language among computers Analogous to addressing envelopes Many different protocols out there Different “layers” use different protocols

Network AddressingNetwork Addressing

Must be unique to each device A single physical device can have several

network addresses Usually divided into two parts: network and

node (both parts can be combined into one address)

May be permanent (static) or temporary (dynamic)

PacketsPackets

Way information moves across the wire Packets can carry data or protocol/control

information only Difference between “packet” and “cell”

How Networks GrowHow Networks Grow File sharing Application sharing Peripheral sharing Client/server applications

– Email– WWW

Multimedia applications

Dividing/Expanding NetworksDividing/Expanding Networks

Why:– Too much traffic– Too many nodes– Distance limitations

How:– Repeaters– Bridges– Routers

Performance TermsPerformance Terms

Bandwidth Throughput Latency (delay) Jitter Loss

Other Aspects/ConsiderationsOther Aspects/Considerations

Security Management

Key PointsKey Points

Standards = Good! Simplicity = Good! (easy to develop) Ethernet = Good! (it’s simple) TCP/IP = Good! (it’s simple)