1. 3.4
Connectivity Methods

2. 3.4 Connectivity Methods Are physical methods
Used with ‘real’ networks
Not just ‘theory’ ideas

3. 2 2 4 WAN Types of Network LAN Client/Server Types of LAN Peer to Peer
Bus
Ring 4
Ways to connect LAN
Mesh
Star

4. 3.4 Connectivity Methods Practical methods for LANs
Practical methods for WANs

5. 3.4 Connectivity Methods Practical methods for LANs
Practical methods for WANs

6. 3.4
Connectivity Methods
Methods for LANs
You need to know the basics for two physical methods used with LAN…
Star
Ring

7. Methods for LAN Ethernet
3.4
Connectivity Methods
Methods for LAN
Ethernet
Ethernet is the most popular physical method or ‘layer’ for LANs.
One key characteristic is its clever protocol
for managing data collisions.
Data Collision
A packet collision can happen when different devices try to transmit at same time.

8. Methods for LAN Ethernet
3.4
Connectivity Methods
Methods for LAN
Ethernet
After detecting a collision, Ethernet makes each device delay by a random amount of time before re-transmitting the packet.
Time delay
That’s called CSMA/CD, or Carrier Sense Multiple Access/Collision Detection.
Making the delay random helps keep the data traffic flowing so network doesn’t go slow.

9. Methods for LAN Token Ring
3.4
Connectivity Methods
Methods for LAN
Token Ring
Token Ring is the most popular physical method for managing a ring LAN.
It also has a clever way to prevent collisions by using a shared ‘token’ to carry the data.
‘Token’
It’s like an empty packet that travels round loop and devices can add their data when their ‘turn’

10. Methods for LAN Token Ring
3.4
Connectivity Methods
Methods for LAN
Token Ring
So whichever device has the token can put data into the network.
When its transmission is complete, the device passes the token along to the next device.

11. Methods for LAN Comparison Ethernet Token Ring
3.4
Connectivity Methods
Methods for LAN
Comparison
Ethernet
Is the most popular physical method used for LANs
Uses collision detection method that makes devices wait a random time
Token Ring
Manages collisions by making devices use a token to take turns to transmit data
Only the device that has the token can send its data across the network

12. 3.4 Connectivity Methods Practical methods for LANs
Practical methods for WANs

13. 3.4
Connectivity Methods
Methods for WANs
ISDN
Integrated Services Digital Network is an old method for transmitting data and voice over phone wires.
Back in the 1990s, ISDN brought fast links to businesses but has now been replaced with new methods.

14. 3.4
Connectivity Methods
Methods for WANs
ADSL
ADSL allows copper phone lines to carry broadband internet.
Phone socket
It separates the frequencies used for voice & data signals.
Router
ADSL microfilter

15. Methods for WANs Leased line
3.4
Connectivity Methods
Methods for WANs
Leased line
A leased line is a popular choice for companies who want a dedicated connection between their sites.
Regional Office
It’s costly – but only carries your data so is guaranteed to give ultrafast speeds.
Head Office

16. 3.4
Connectivity Methods

17. MAN Metropolitan Area Network Metropolitan means a big area, eg a city
3.4
Connectivity Methods
MAN
Metropolitan Area Network
Metropolitan means a big area, eg a city
So a MAN is bigger than a LAN but smaller than a WAN

18. 3.4
Connectivity Methods
Voice
PSTN
The Public Switched Telephone Network is the world's collection of interconnected phone networks
It was created for voice but now includes all the fibre links that also carry our data today.

19. 3.4
Connectivity Methods
Voice
Cellular
They’re called cellular networks because they’re built from small areas called ‘cells’ around base stations.
These 3G & 4G networks were built for voice – but data is now also key .

20. 3.4
Connectivity Methods
Satellite
Voice & Data
Satphones connect to orbiting satellites, not cellular networks. They’re popular for voice calling in remote locations.
Communications satellites can also provide data services such as GPS and Internet access.

21. 3.4
Connectivity Methods