Lecture 9: Internetworking

Question 1

Name five devices that might be used to join networks together.

Answer 1

Hub, switch,, bridge, router or access gateway.

Question 2

When connecting LANs must consider the following:

Answer 2

Frame format (conversion), payload size (max allowed), data rate (buffering), address bit order (conversion).

Question 3

What are two responsibilities of the network layer?

Answer 3

Logic addressing: translating addresses across connected networks.
Routing: determining path to take from source to destination.

Question 4

Name three main levels of addressing. Give examples.

Answer 4

Application Layer: HTTP, www.griffith.edu.au.
Network Layer: TCP/IP, 132.234.112.9
Datalink Layer: Ethernet MAC, 00-0C-00-F5-03-5A

Question 5

What is a subnet?

Answer 5

It is a smaller “sub-network” within a larger network.

Question 6

What is a subnet mask?

Answer 6

A 32bit word with all 1s that indicate the netid subnet id and all 0s that designate the hostid.

Question 7

What does a switch/router do?

Answer 7

Allows multiple computers to connect each other.

Question 8

What are the two types of switching? Describe them.

Answer 8

1) Circuit switching: establishes dedicated point-to-point connection for two computers at a given time.
2) Packet switching: any device can simultaneously talk to any number of other devices.

Question 9

What are the two types of packet-switching?

Answer 9

Connectionless: each packet travels independently along network and no error control. IP is an example.
Connection-Oriented: connection is established between source and destination and all packetrs in message travel along the same path. Known as virtual circuit.

Question 10

What are connection-oriented and connection-less services?

Answer 10

Connection oriented: Circuit Switching (telephone) or Packet switching
(Virtual circuit – ATM)
Connection less: Packet switching (Datagram - UDP)

Question 11

What is routing?

Answer 11

The process of determining path through network to get to destination.

Question 12

List 4 methods of routing.

Answer 12

Static, random, broadcast and dynamic.

Question 13

What devices would be used to:
a) connect segments of a LAN.
b) connect LANs to LANs.
c) connect LANs to WANs.
d) extend range of physical medium.
Additionally, state the OSI layer they’re working at.

Answer 13

a) Switch (Datalink).
b) Bridge (Datalink).
c) Router/Gateway (Network).
d) Repeater/Hub (Physical).