Unit 1: Lesson 7 - Network Hardware

UNIT 1: Lesson 7 - Network Hardware

There are security issues when using WAP's

Access should always be password protected

Consider not broadcasting the SSID (service set identifier)

Use encryption so data is unreable if intercepted.

Wireless Access Points (WAP)

Disadvantages

As well as security considerations, using wireless connections is normally slower than a wired connection

Susceptible to interference

Range issues - especially in old buildings

More expensive* than using wired connections

In the old days, all connections were made using some kind of cable

Nowadays, mobile devices have popularised the used of wireless systems.

Wireless Access Points have dedicated radio channels that devices can connect to

Data passing into the WAP is then fed into the network it is physically connected to by wire.

Hub

Sending data

The Switch

Advantages

Hubs are cheap

Data gets to where it needs to go

Hub

Disadvantages

Lot's of redundant data is sent

Causes networks to slow down

Shares bandwidth - If hub has 100Mbps bandwidth and someone is sharing a large file all nodes will experience drop in performance

On a network with multiple nodes, we need a piece of hardware to direct these packets over the network

The most basic example is the use of a hub

The hub sits at the centre of the network, and each device is connected to it.

When a packet is sent, it is received by the hub, and then sent to EVERY CONNECTED NODE

This means that the packet gets sent to where it needs to go, since all devices receive it.

Fine for small, low traffic networks - not so good for big networks!

Repeaters

• We know that TCP/IP networks utilise packets to send data

• We know that these data packets contain the source and destination address, but how do they get there?

NIC

Network Interface Controller/ Network Interface Card

Converts data into a format that can be transmitted along a medium - whatever that medium may be...

NIC

Looks like a hub and also physically sits at the centre and joins nodes together

Switches are intelligent and only send packets to the intended recipient

Much more efficient than hubs

Dedicated bandwidth per port

More expensive than hubs

• Computers understand binary so the NIC needs to convert the data into some kind of format that can be measured and interpreted as either a 1 or a 0

• This could be a voltage level in the case of copper links, radio waves for Wi-Fi or light levels for fibre optic links.

• The receiving device will convert and interpret this back into binary upon receiving the data

• Media Access Control Address - unique to each NIC

The longer the distance we send our signal the weaker they get. To overcome this we can use a repeater.

The repeater takes in a signal, boosts it, and then send it along the path again

Starter

Complete the starter on communication mediums!

The Bridge

When the bridge recieves data, the address is examined to see if it resides on the local LAN.

If it does then it is passed to the hub/switch on that LAN

If it isn't, the packet is sent across the bridge to the hub/switch on the connected LAN

This is only possible if both LAN's are using the same network protocols

Routers

Network Hardware

Switches and hubs connect devices on the same network together

Bridges connect seperate networks together - literally acting as a bridge between networks

In order to create a network, you need specialist hardware to physically connect your nodes together as well as hardware to manage how your data is passed along to them.

Learning Objectives

Routers are used to send messages to other LAN's on the internet

They are sophisticated devices that intend to transfer data across the fastest possible route

The router contains a micro computer that records information about all of the networks that it is connected to.

Routers are housed where multiple connection meet

These meeting points are called network gateways; in the case of the internet these are housed in data centres

When the router finds that the most direct route is busy, an alternative route is selected to send the data packet

The information on possible paths is held in the router table

These tables are constantly updated to maintain accurate routes

When data is received, it compares the destination address against the router table and passes the packet to the next router on the fastest route at that time

This is then repeated by the receiving router until the data has reached it's destination.

To understand the hardware required to create a network

To understand the function of network hardware

To be able to identify where different pieces of hardware may be used on a LAN

Mini plenary

Complete the network diagram by labeling the hardware components

Hybrid Network hub

Task

Plenary - Taboo

Access the following resource and complete to a high level of detail:

Shared:\Computing - ICT\KS5 - CamTech Level 3\LO1\1.5\Lesson 7\Network Hardware questions

• Get into two teams

• One person will come to the front and a word will appear behind them. Their team will have to describe the word to them without actually saying the word!

What many people refer to as their 'router' is actually a hybrid device.

WiFi access point

Hub

Modem

Router

Modems

Modulate Demodulate

Telephone lines transmit data in analog waves

Computers understand digital information

The modem acts as a translator between these two formats

Modulate the digital signal to analog to send

Demodulate the analog signal to digital when receiving data via telephone line