2: Computer Networks Overview

Question 1

Protocol ?

Answer 1

A set of rules (a language) for communication between two or more computers.

Question 2

TCP ?

IP ?

Answer 2

Transmission Control Protocol.

Internet Protocol.

Question 3

How many protocols do modern computers use ?

Answer 3

Thousands.

Question 4

What is an open system?

Answer 4

A system which has a public architecture (protocols, traffic source code) visible to all.

Anyone can:

• Connect
• Modify

an open system.

Question 5

To whom belongs an open system ?

Answer 5

It can belong to someone.

Question 6

Who developed Open-Source Software ?

Answer 6

A public community of developers, eg Linux OS.

Question 7

3 examples of open systems?

Answer 7

• OS: UNIX, Linux
• Protocols: IP, TCP
• Systems: Internet, WWW

Question 8

Examples of non-open systems ?

Answer 8

• OS: MS Windows
• Protocols: Military Protocols
• Systems: B2B

Question 9

Advantages of open systems?

Answer 9

• Users have control over an implementation
• Bugs are identified and fixed early
• Adaptable to different domains

Question 10

Disadvantages of open systems ?

Answer 10

• No central common version of standard
• Bugs may not be fixed compatibly
• Systems may not be always portable

Question 11

Lines of code for Linux vs MS windows ?

Answer 11

Linux: 1m
Windows: 50m

Question 12

Computer Network ?

Answer 12

A collection of computers that are physically and logically connected together to exchange information.

Question 13

Network topology ?

Answer 13

A way to connect electronic devices together.

Eg: Internet is an open systems which connects computer networks together.

Question 14

Draw a bus topology of a network.

Answer 14

Printer, Web Server, Computer
     |                |               |
|----------------------------------|
|----------------------------------|
           |                   |
Computer,        Camera

Question 15

Draw a star topology of a network.

Answer 15

Web server
Printer
Computer
Camera
Computer 

all pointing to Backplane

Question 16

Draw a ring topology of a network.

Answer 16

Same as start but with a bigger circle in the middle.

Question 17

Circuit-switched networks ?

Answer 17

• Dedicated line for communication between 2 people
• High quality of service
• Inefficiently used network resources
• One break = end of convo

Question 18

How are packet-switched networks messages sent?

Answer 18

• Message broken into individual packets sent separately.

- Potentially different routes, same destination.

Question 19

How are packet-switched networks messages numbered?

Answer 19

Sequentially, and can be re-assembled at destination.

Like sending several postcards instead of one long letter.

Question 20

What type of a network is the Internet ?

Answer 20

Packet-Switched.

Question 21

How long is a packet typically ?

Answer 21

400-600 bytes long.

Question 22

What was the Internet’s original name and short form ?

What was its goal ?

Answer 22

Advanced Research Projects Agency (ARPA)’s Network: Arpanet.

Connect Universities to military sites.

Question 23

Who created WWW and when?

Answer 23

Tim Berners-Lee in 1990.

Question 24

What was the goal of WWW?

Answer 24

• A naming system for every element on the Internet (URL).
• A method for documents to contain internal references to these names (HTML)
• The concept of the web-server to store data and the web-browser to display the data.

Question 25

What’s the full form of URL ?

Answer 25

Uniform Resource Locator

Question 26

What are the main components of the architecture of the Internet ?

Answer 26

• Router: connects network to Internet
• Network core: interconnected routers
• Network edge: applications and hosts
• Hosts: computers connected to a network