Networking basics

Unit objective: Describe network and Internet

connection types, and differentiate between basic networking devices

Topic A

Topic A: Networks Topic B: Internet connection types Topic C: Network devices

Network types

Personal area network Local area network Metropolitan area network Wide area network

Star topology

Nodes connected to central network connectivity device

Central device distributes information packets

Single break doesn’t affect other nodes

If central device fails, all communication fails

Bus topology

Continuous line is formed Nodes connected to next in line Coaxial and T-connectors End of line uses terminating device Terminator absorbs the data signal Information passes through each node once Node determines if data is addressed to it Simple and inexpensive design Single break in line stops all communication

Ring topology

Each node is connected to two nodes on either side of it

All nodes form a continuous loop Data token passes around the ring Node can transmit data if it has the token

Mesh topology All nodes have

independent connections to all other nodes

Very fault-tolerant and scalable design

Nodes need multiple network cards

Complex wiring scheme Most often wide-area

or campus links Might not be fully meshed

Hybrid topology Two or more types of network

topologies combined into one network

Topic B

Topic A: Networks Topic B: Internet connection types Topic C: Network devices

POTS/PSTN

Dial-up system over telephone lines Connection isn’t continuous Phone and data share line; only one can be used at

a time Max data speed 56 Kbps Modem bonding combines speed of multiple

modems

ISDN

Uses phone lines– 2 data channels– Control signal channel

Data not converted to analog Terminal adapter Each data channel can transmit data at up

to 64 Kbps Two channels can be combined to move

data at speed of 128 Kbps Basic Rate Interface (BRI) PRI: 23 channels + control channel

DSL

High-speed data and voice transmission line

Uses telephone wires for data transmission

Carries digital data at frequencies above voice transmission

Can transmit voice and digital data on same line at same time

Cable

Uses transceiver (cable modem) to send and receive data

Uses same line as cable TV Different frequencies Optional VoIP

Fiber

Not as common as cable and DSL Typical configurations

– FTTN– FTTC– FTTP

Satellite

Useful in rural areas Uses dish mounted on building to communicate

with stationary satellite in orbit Downlink uses satellite Uplink sometimes dial-up

WiMAX

802.16 Air Interface Standard Worldwide Interoperability of Microwave

Access Doesn’t require a line of sight

Cellular

Provided by major cell phone companies Access via cell signal with Internet-capable

phone or laptop using cellular network PC card

Faster than dial-up; slower than DSL or cable

Topic C

Topic A: Networks Topic B: Internet connection types Topic C: Network devices

Ethernet hub

Used to wire Ethernet star Connects devices that use BNC or

RJ-45 connector Easy to configure

Data traffic through a hub

Hub types

Passive Active Switching Intelligent

Bridges

Switches

Connects like a hub, but learns MAC addresses and uses them to make forwarding and filtering decisions

Benefits over a hub PoE

Router

Creates a path between individual networks

Can use to divide larger network into smaller, more manageable networks

Routing between network segments

Access points

Modems

Connect computer to computer through phone line

External or internal Converts signals from digital to analog and

back

Modulation and demodulation

Connections

Network attached storage

Devices that provides storage services Multiple hard drives Self-configuring

Firewalls

Stands between LAN and Internet Hardware firewall

Voice over IP

VoIP Digital phone service Telephone calls over digital network Converts analog signals to digital back

to voice Speak with anyone with a regular

phone number Protocols

– SIP– RTP

Network appliances

Load balancers Proxy servers Content filters

Unit summary

Described network and Internet connection types, and differentiated between basic networking devices