Network Topologies

Question 1

What is a network Topology?

Answer 1

A network topology is a way of describing the interconnections and cabling of a group of computers

Question 2

What is a physical Topology

Answer 2

Physical topology is how the devices or a group of computers are physically connected.

Question 3

What is a logical Topology?

Answer 3

Logical topology is how the network devices communicate with each other

Question 4

What is a star topology?

Answer 4

• Each device on the network is connected to a central communication device such as a Hub or switch

Question 5

What happens if one cable breaks in a star topology?

Answer 5

If one network cable breaks, the workstation connected to it also fails, but it does not affect the rest of the network

Question 6

What happens if the central hub fails in a star topology?

Answer 6

if the central hub fails the whole network will be inoperative as each workstation relies on the central hub for communication.

Question 7

What is the central device - hub?

Answer 7

• central device - hub: network signals reach the hub that are sent out to all connected devices.
• The hub just repeats them all on its connections and does not process the signals

Question 8

What is the central device - Switch?

Answer 8

• Central device - switch: uses a table that maps each device to the port it is connected to.
• switch is able to direct message to correct recipient

Question 9

STAR TOPOLOGY - What is security and speed like?

Answer 9

• Improves security and speed
• messages are transmitted along a specific path from source to destination

Question 10

STAR TOPOLOGY - What is reliability like?

Answer 10

• Switch or hub is a central point of failure
• if it fails, the connected devices will be unable to communicate or access network resources
• failure of individual cables will not affect the network

Question 11

STAR TOPOLOGY - What are the advantages?

Answer 11

• If one of the network cables breaks only the computer connected to that cable is affected.
• Fast response time and no problems with data collision as each workstation has its own cable.
• Security can be installed at the central hub.

Question 12

STAR TOPOLOGY - What are the disadvantages?

Answer 12

• All communication takes place via the central hub and if it fails the whole network will break down.
• Uses the most cable which can be expensive to purchase and install. Also long cable runs can cause the data signal to degrade.

Question 13

BUS TOPOLOGY - What is a Bus Topology?

Answer 13

• The bus topology has one cable that connects every device on the network which is called the backbone
• Each device is connected to the main capable to join the network

Question 14

BUS TOPOLOGY - What is the backbone?

Answer 14

• The one cable that connect to a every device on a network.

Question 15

BUS TOPOLOGY - What is a terminator?

Answer 15

• At the end of the main capable there is a device called the terminator
• The terminator absorbs signals when they reach the end to prevent interference

Question 16

BUS TOPOLOGY - What are the Operations like?

Answer 16

• Network signals (representing messages between the devices) are sent through the main cable to reach all connected devices.
• Each message contains a destination address that identities its intended recipient
• MAC address that is hard coded into the Network Interface controller

Question 17

BUS TOPOLOGY - What happens when there is a collision?

Answer 17

• If two or more devices try to transmit at the same time, it will cause a collision
• if a collision occurs, the devices must stop and try again later
• causes the overall performance of the network to deteriorate

Question 18

BUS TOPOLOGY - What is the security like?

Answer 18

• Transmitting signals is a security issue
• every device attached to the bus can “read” every message
• message needs to be encrypted to not be read

Question 19

BUS TOPOLOGY - What are the Reliability like?

Answer 19

• failure of the main bus capable will bring the whole network to a stop
• if there is failure in the cable that connects a single device to the bus, it will only affect just that device

Question 20

RING TOPOLOGY - What is a ring topology?

Answer 20

Each device is connected to exactly to other devices creating a single pathway - ring - along which signals travel

Question 21

RING TOPOLOGY - What does it mean that a Ring is Uni-directional?

Answer 21

• A ring can be uni-directional : the signals can only travel in one direction
• break in the capable can lead the network to fail

Question 22

RING TOPOLOGY - What does it mean that a Ring is bi-directional?

Answer 22

• signals travel in either direction so the network has more resilience

Question 23

RING TOPOLOGY - What is a token ring network?

Answer 23

• Token ring network - a special signal called the token circulates the network
• Devices can only communicate when they have the token - there will be no collisions

Question 24

RING TOPOLOGY - What direction can they travel in?

Answer 24

• Well they can be bi-directional or uni-directional

Question 25

MESH TOPOLOGY - What is a Mesh Topology?

Answer 25

- There is no central communication point - multiple paths between the communication devices that form the network - provides many communication pathways - no critical point of failure as every communication path has several alternative pathways - allows the most efficient paths to be used

Question 26

What is a local area network?

Answer 26

- Local area networks: two or more computers connected together within a small geographical area

Question 27

What is a wide area network?

Answer 27

is a network that connects two or more networks over a wider geographical area.

Question 28

What is a Switch?

Answer 28

A switch sends each communication to the specific computer it is intended for

Question 29

What do both wired and wireless networks have?

Answer 29

Both wired and wireless networks have a MAC address

Question 30

What is the difference between a physical and logical Topology?

Answer 30

- Physical topology of a network defines how the devices are physically connected - The logical topology defines how the devices communicate across the physical topologies

Question 31

What is Cloud Computing?

Answer 31

- Cloud computing – is imaginative term for internet computing, using remote servers run by organisations such as DropBox, Microscoft or thousands of other specialists software companies - Multiple servers -> Virtual environment - Scale your resource usage in near real time. - The mutliple severs behave as one - Pay to what you need/use

Question 32

How does a physical bus topology work?

Answer 32

- The file server is connected to the main bus for data distribution to all the workstations. - Data can be transmitted in either direction along the main cable, and workstations can communicate with their peers. - A range of peripherals can also be connected to the main bus for shared usage. - The physically wired star topology can be dynamically reconfigured into a logical bus topology by making use of appropriate protocols and specialist equipment such as routers and switches.

Question 33

BUS TOPOLOGY - What are the advantages?

Answer 33

- If one workstation fails it does not affect the rest of the network. - Is cheaper to install as it uses the least cable as the cost of network cabling (particularly fibre optic) and the cost of network cable installation can be significant.

Question 34

BUS TOPOLOGY - What are the disadvantages?

Answer 34

If the main network cable breaks anywhere then none of the workstations can access the network. If there is heavy network traffic the system performance will fall off dramatically. If the main bus fails all computers are affected.