CS Free MCQ Bank

[ Option C ]

WiFi and WiMAX are two popular wireless communication technologies, but they differ in coverage and standards. WiFi, based on the IEEE 802.11 family of standards, is mainly used for creating local area wireless networks with coverage typically up to 100 meters.

On the other hand, WiMAX is defined under the IEEE 802.16 standard and is designed for broadband wireless access over much larger distances, covering up to several kilometers.

The IEEE stands for Institute of Electrical and Electronics Engineers. IEEE develops global standards and supports a large community of engineers and scientists worldwide.

• 802.3 : Ethernet (Wired LAN standard, Data Link & Physical Layer).
• IEEE 802.5 : Token Ring LAN.
• 802.11 : WiFi (Wireless LAN).
• 802.15 : Wireless Personal Area Network (WPAN, Bluetooth).
• 802.16 : WiMAX (Worldwide Interoperability for Microwave Access, Broadband Wireless Access).
• IEEE 1394 : FireWire (High-speed serial bus for multimedia devices).

[ Option B ]

WPA2 (Wi-Fi Protected Access 2) is the most widely used Wi-Fi security protocol. It was introduced in 2004 and uses AES (Advanced Encryption Standard) for strong encryption and security.

[ Option A ]

The standard port number for HTTP (Hypertext Transfer Protocol) is 80. Port 80 is the default port used for web servers serving unencrypted traffic over HTTP.

[ Option A ]

SMTP (Simple Mail Transfer Protocol) is the protocol used to transfer email messages from the sender's mail server to the recipient's mail server across the internet. It is an application layer protocol that uses TCP to reliably send and relay email messages between servers until reaching the destination server.

• SMTP takes care of the sending and forwarding of emails across networks but does not handle retrieving or storing emails on client devices.

The IMAP (Internet Message Access Protocol) and POP (Post Office Protocol) are involved in email retrieval from mail servers to client devices, not in sending emails through the internet. UDP (User Datagram Protocol) is a transport protocol used for fast, connectionless communication. 

[ Option D ]

Physical Layer of the OSI model deals with the transmission of raw bitstreams over a physical medium. Network devices operating at the physical layer are responsible for transmitting and regenerating signals without interpreting the data.
Repeaters regenerate and amplify signals to extend the range of a network without any processing of the data.
Hubs serve as basic central connection points in Ethernet networks, forwarding signals to all ports and operating purely at the physical layer.

[ Option A ]

An IPv4 address is a 32-bit number used to uniquely identify a device on a network. It is usually represented in dotted decimal notation as four decimal numbers separated by dots, e.g., 192.248.0.1, where each number represents 8 bits.

[ Option A ]

Ethernet networks use MAC (Media Access Control) addresses as their physical addresses, which are permanently imprinted on the Network Interface Card (NIC) by the manufacturer. A MAC address is 48 bits long, equivalent to 6 bytes, and is usually represented in hexadecimal notation. 
This unique identifier ensures that devices within the same local network can correctly recognize and communicate with each other.

[ Option C ]

ARP (Address Resolution Protocol) is a network protocol used to map an IP Address (Logical Address) to a physical MAC Address (Physical Address) in a network.
For example, when a computer wants to send data to another device on the same network, it first uses ARP to find out the MAC address corresponding to the known IP address. This ensures that the data packets are delivered to the correct device.

[ Option C ]

FTP (File Transfer Protocol) is used to transfer files between a client and a server on a network. In FTP, data can be transferred using different transmission modes that determine how the file data is sent over the connection.

• Stream Mode is the default mode where data is sent as a continuous stream of bytes without any additional processing until the end-of-file is reached. TCP ensures reliability.
• Block Mode transfers data in blocks, where each block contains a header that describes the block size and type. This is useful for structured data transfers.
• Compressed Mode compresses the data before transmission, reducing the size of the file to speed up transfer, usually using run-length encoding.
   

[ Option B ]

Single Parity Check, Checksum, and Cyclic Redundancy Check (CRC) are primarily error detection methods. They detect if an error has occurred in the transmitted data but do not necessarily correct the errors.
Hamming Distance refers to Hamming Code, which is a method used for both error detection and error correction. It can detect and correct single-bit errors by adding redundant bits to the data.

[ Option B ]

A Network Layer firewall functions as a Packet Filter. It examines and manages the flow of data packets according to rules defined by IP addresses, Port Numbers, and communication protocols. Operating at the Network Layer (Layer 3) of the OSI model, this type of firewall makes decisions on whether to permit or deny packets without analyzing the actual data content inside them.

[ Option B ]

HTTP (Hypertext Transfer Protocol), is the standard protocol used to transfer web pages over the internet. It works at the Application Layer, allowing communication between web browsers and web servers. When a browser requests a webpage, HTTP facilitates sending that request to the server and receiving the webpage content, such as HTML, images, and videos, in response.

This protocol follows a client-server model, where the browser acts as the client initiating the request, and the server processes the request and sends back the required webpage data. Through this request-response communication, HTTP enables users to access and view websites on the internet efficiently.