2.02 - Network Topologies

Question 1

What does a data communication system require?

Answer 1

1. A sender
2. A reciever
3. A transmission medium
4. A message
5. A protocol

Question 2

What are the 2 data transmission mediums?

Answer 2

Air or cables

Question 3

What are the 3 data transmission modes?

Answer 3

Simplex mode
Half duplex mode
Full duplex mode

Question 4

Describe

Simplex mode

Answer 4

A data transmission mode where data only flows in one-way

Question 5

Describe

Half Duplex mode

Answer 5

A data transmission mode where data can flow either way but not simultaneously

Question 6

Describe

Full duplex mode

Answer 6

A data transmission mode where can flow both ways simultaneously

Question 7

How can messages be sent in a data communication system?

Answer 7

As:
Broadcasts
Multicasts
Unicasts

Question 8

Describe

Broadcast communication

Answer 8

One-to-all Communication

Question 9

Describe

Multicast communication

Answer 9

Communication from one source to many destinations

Question 10

Describe

Unicast communication

Answer 10

One-to-one communication

Question 11

What is the simplest isolated network topology?

Answer 11

Point-to-point communcation

Question 12

What is Point-to-point connection?

Answer 12

The simplest isolated network topology which is a dedicated link that can only transmit unicast messages

Question 13

What did early LAN topologies use?

Answer 13

Either ring or bus topology

Question 14

Why isnt ring topology no longer important?

Answer 14

It isnt being used much nowadays

Question 15

Describe

The bus topology

Answer 15

It has only one link but is shared by several end-systems and there is no direct connection between any pair of these end-systems

Question 16

Name

Another name for bus topology

Answer 16

Multi-point connection

Question 17

Why is bus topology resilient?

Answer 17

Because a fault in an end-system or in the link to it, does not affect the use of the network by the other end-systems

Question 18

Describe

The mesh topology

Answer 18

A fully connected mesh topology has each end-system connected to each other with point-to-point connections and messages can be uni/multi/broad cast

Question 19

When can a mesh topology be used?

Answer 19

Can be used when individual LAN switches are connected in a network, and it is essential for the connection of routers within the infrastructure of the internet

Question 20

Describe

The star topology

Answer 20

Star topology had each end-system connected to a central device with point-to-point connections and messages can be uni/multi/broad cast

Question 21

What is the central device in the star topology?

Answer 21

It is a specialised device with the purpose of connecting other devices in the network

Question 22

What is a similarity and difference between star and bus topology?

Answer 22

The failure of an end-system or its link leaves the other end-systems unaffected in both topologies however a fail in the central device will affect all the end-systems in star topology

Question 23

What is the usual way to configure a network?

Answer 23

Using the star topology

Question 24

Why is the star topology the usual way to configure a network?

Answer 24

Because the central device can connect the network to other networks and the Internet

Question 25

What is a hybrid network?

Answer 25

A hybrid network is a collection of LANs with different topologies or supporting technologies, and a special connecting device is needed to ensure it is fully functional

Question 26

Is it advantageous or disadvantageous to connect a new topology LAN to existing LANs. Explain.

Answer 26

It is often advantageous to connect a new topology LAN to existing LANs where it is not sensible or possible to use the existing topology for the new LAN, such as connecting a new wireless LAN to an existing wired LAN