Chapter 15

Question 1

What is switch network

Answer 1

A network which have electronic device with multiple ports and multiple computers can attach to it.

Question 2

What is hub

Answer 2

It is similar to switch network with the difference that inside circulatory of hub formulates a bus.

Question 3

Does only 2 computers can communicate over hub at a time and more than 2 computers can communicate over switch at a time

Answer 3

Yes

Question 4

What is data rate of hub

Answer 4

R

Question 5

What is data rate of switch

Answer 5

nR/2

Question 6

What is WAN

Answer 6

Wide area network for country / continent

Question 7

Why we use WAN

Answer 7

• Bandwidth

- Scalability

Question 8

What are packet switches

Answer 8

These switches are capable to switch whole packets. It is a full fledged computer.

Question 9

What is the basic building block for WAN

Answer 9

packet switch

Question 10

What is store and forward on switch packet

Answer 10

In store part, a switch packet must have a memory buffer and it keeps packets in it. In forward, it forward packet to next path.

Question 11

What is hierarchical addressing in WAN

Answer 11

We divide physical address into 2 parts. First part is for packet switch and 2nd part is for port. e.g. address[2,6]

Question 12

What is next-hop forwarding

Answer 12

It means that packet switch must have at least one outgoing connection for forwarding. Its example is a train going from karachi to peshawar. It stops in lahore, islamabad and then go to peshawar. from karachi its next hop is lahore, from lahore its next hop is islamabad and so on. So a packet does not need to know its destination, all its need to know its next-hop.