Learning Objectives:

• Learn about the components of LANs, including network devices (e.g., routers, switches, hubs), cables, and network interfaces.
• Understand LAN protocols, such as Ethernet and Wi-Fi, and their role in data communication within LANs.
• Explore the architecture of LANs, including the physical and logical layout, addressing schemes, and data link layers.
• Analyze the factors influencing LAN performance, including bandwidth, latency, and network congestion

LAN is an abbreviation for Local Area Network. This network is a more advanced version of PAN that can be used to share data and devices between two or more PCs or devices. A LAN is typically confined within a small workplace, school, hospital, or building. It can be built with low-cost hardware such as hubs, switches, routers, and cables.

Gateway_firewall.svg: Harald Mühlböckderivative work: Ggia, CC BY-SA 3.0, via Wikimedia Commons

Solved Example: 9988-01

A computer network which is used within a building is called:

A. WAN

B. MAN

C. LAN

D. SAN

Correct Answer: C

Solved Example: 9988-02

LAN works on which of the following Layers?

A. Physical

B. Datalink

C. Datalink and Network

D. Physical and Datalink

Correct Answer: D

Solved Example: 9988-03

Ether LAN uses:

A. Polar encoding

B. Differential Manchester encoding

C. Manchester encoding

D. NRZ

Correct Answer: C

Solved Example: 9988-04

Consider two hosts X and Y, connected by a single direct link of rate 10⁶ bits/sec. The distance between the two hosts is 10,000 km and the propagation speed along the link is 2 × 10⁸ m/sec. Host X sends a file of 50,000 bytes as one large message to host Y continuously. Let the transmission and propagation delays be p milliseconds and q milliseconds, respectively. Then the values of p and q are:

A. p = 50 and q = 100

B. p = 50 and q = 400

C. p = 100 and q = 50

D. p = 400 and q = 50

Transmission time = $\dfrac{\mathrm{Frame\ Langth}}{\mathrm{Bandwidth}}= \dfrac{4 \times 100}{10 \times 100}$ = 400 msec

Propagation time = $\dfrac{\mathrm{Distance}}{\mathrm{Propagation\ Speed}} = \dfrac{10000 \times 1000}{2 \times 10^8}$ = 50 msec

Correct Answer: D

Solved Example: 9988-05

Computers connected to a LAN can:

A. Run faster

B. Go on line

C. Share information and/or share peripheral equipment

D. E-mail

Correct Answer: C

Solved Example: 9988-06

A computer in a network that cannot be accessed outside of the local network unless given permission is called:

A. Intranet

B. Internet

C. Middleware

D. Modern

Correct Answer: A

Learning Objectives:

• Comprehend the various WAN technologies, including circuit-switched networks, packet-switched networks, and leased lines.
• Learn about the components of WANs, including routers, switches, modems, and data communication equipment.
• Understand WAN protocols, such as PPP (Point-to-Point Protocol) and HDLC (High-Level Data Link Control), and their role in data communication across WANs.
• Analyze the factors influencing WAN performance, including bandwidth, latency, and quality of service (QoS).

A Wide Area Network (WAN) covers a huge geographical area, such as an entire city, region, country, or continent. A wide area network (WAN) connects computers and LANs in separate cities or countries using telephone lines, satellites, microwave radio links, and fibre optic cables. In WAN, a repeater is used to spread the signal across a long distance while maintaining signal intensity. The internet is an example of WAN.

Solved Example: 9987-01

WAN stands for:

A. Wide Area Network

B. Wide Access Network

C. World Area Network

D. World Access Network

Correct Answer: A

Learning Objectives:

• Comprehend the role of key Internet protocols, such as TCP/IP (Transmission Control Protocol/Internet Protocol) and HTTP (Hypertext Transfer Protocol), in enabling data communication and web services.
• Learn about IP addresses, including IPv4 and IPv6, and how they are used to uniquely identify devices on the Internet.
• Familiarize yourself with key Internet-related protocols and technologies, including SMTP (Simple Mail Transfer Protocol), POP3 (Post Office Protocol), IMAP (Internet Message Access Protocol), and FTP (File Transfer Protocol).
• Recognize the importance of internet security, including concepts like firewalls, encryption, and VPNs (Virtual Private Networks).

The Internet is a global, interconnected computer network in which every computer connected to it can exchange data with any other connected computer. The Internet is a network of computers spanning the globe. It is also called the World Wide Web. The vast collection of computer networks which form and act as a single huge network for transport of data and messages across distances which can be anywhere from the same office to anywhere in the world.

It is the largest network in the world that connects hundreds of thousands of individual networks all over the world. The popular term for the Internet is the “information highway”. Rather than moving through geographical space, it moves your ideas and information through cyberspace – the space of electronic movement of ideas and information.

WWW (world wide web) WWW is a set of protocols that allows to access any document on the internet through the naming system based on Uniform resource location. It is a mechanism that links together information stored on many computers. With a web browser, one can view the pages that may contains text, images, videos and other multimedia and navigate between them using hyperlinks. The world wide web allows spreading of information over the internet through an easy to use and flexible format.it thus plays an important role in popularizing use of the internet. The WWW was invented in 1989. Users of the internet are attracted to the WWW because it is very interactive. It combines text, graphics, sound, animation and moving pictures making it a rich communication medium.

Solved Example: 9983-01

IPv6 addresses have a size of:

A. 64 bits

B. 128 bits

C. 256 bits

D. 512 bits

Correct Answer: B

Solved Example: 9983-02

The DNS maps the IP addresses to:

A. A binary address as strings

B. An alphanumeric address

C. A hierarchy of domain names

D. A hexadecimal address

Correct Answer: C

Solved Example: 9983-03

Which of the following internet service is appropriate to access the computer of your office from home?

A. www

B. IRC

C. FTP

D. Telnet

Correct Answer: D

Solved Example: 9983-04

Which of the following is not e-mail protocol?

A. POP

B. IMAP

C. SMTP

D. FTP

Correct Answer: D