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"Networking 101: Basics"
Jim Gogan
INLS184
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?
LANs
 WANs
 MANs
 internets
 Internet
 Intranet

Components of a LAN
Cable
 Workstations/Servers
 Interface cards (NICs)
 Hubs/switches/etc.
 Peripherals
 Network protocols

Cable

Types of Cables
– Coaxial cable
– Twisted pair
– Fiber optics

Wireless
Cabling Topologies
Daisy Chain
 Bus
 Ring
 Star

Daisy Chain
Simplest to do
 One device hooked to device after it
 If broken, all connections are lost
 Daisy Chain network example: original
LocalTalk

Bus
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

Ring
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

Star
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

Workstations
The computer on an individual’s desk
 May have its own local devices/peripherals
as well as access to networked peripherals

Servers
Workstation (often higher end) with specific
functions
 Usually provides services:

– File services
– Web services
– Email services
Interface cards
Connect individual devices to network
 Must match type of device and type of cable

Hubs and Switches and
Network Devices
Depends on type of network installed
 More about these later …...

Peripherals
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

Protocols
Common language among computers
 Analogous to addressing envelopes
 Many different protocols out there
 Different “layers” use different protocols

Network 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)

Packets
Way information moves across the wire
 Packets can carry data or protocol/control
information only
 Difference between “packet” and “cell”

How Networks Grow
File sharing
 Application sharing
 Peripheral sharing
 Client/server applications

– Email
– WWW

Multimedia applications
Dividing/Expanding Networks

Why:
– Too much traffic
– Too many nodes
– Distance limitations

How:
– Repeaters
– Bridges
– Routers
Performance Terms
Bandwidth
 Throughput
 Latency (delay)
 Jitter
 Loss

Other Aspects/Considerations
Security
 Management

Key Points
Standards
 Simplicity
 Ethernet
 TCP/IP

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Good!
Good! (easy to develop)
Good! (it’s simple)
Good! (it’s simple)