1. A single channel is shared by multiple signals by ____________
a) analog modulation
b) digital modulation
c) multiplexing
d) phase modulation
Explanation: In communication and computer networks, the main goal is to share a scarce resource. This is done by multiplexing, where multiple analog or digital signals are combined into one signal over a shared medium. The multiple kinds of signals are designated by the transport layer which is the layer present on a higher level than the physical layer.
2. Wireless transmission of signals can be done via ___________
a) radio waves
b) microwaves
c) infrared
d) all of the mentioned
Explanation: Wireless transmission is carried out by radio waves, microwaves and IR waves. These waves range from 3 Khz to above 300 Ghz and are more suitable for wireless transmission. Radio waves can penetrate through walls and are used in radio communications, microwaves and infrared (IR) waves cannot penetrate through walls and are used for satellite communications and device communications respectively.
3. The data link layer takes the packets from _________ and encapsulates them into frames for transmission.
a) network layer
b) physical layer
c) transport layer
d) application layer
Explanation: In computer networks, the data from application layer is sent to transport layer and is converted to segments. These segments are then transferred to the network layer and these are called packets. These packets are then sent to data link layer where they are encapsulated into frames. These frames are then transferred to physical layer where the frames are converted to bits. Error control and flow control data is inserted in the frames at the data link layer.
4. Which of the following tasks is not done by data link layer?
a) framing
b) error control
c) flow control
d) channel coding
Explanation: Channel coding is the function of physical layer. Data link layer mainly deals with framing, error control and flow control. Data link layer is the layer where the packets are encapsulated into frames.
5. Which sublayer of the data link layer performs data link functions that depend upon the type of medium?
a) logical link control sublayer
b) media access control sublayer
c) network interface control sublayer
d) error control sublayer
Explanation: Media access control (MAC) deals with transmission of data packets to and from the network-interface card, and also to and from another remotely shared channel. The MAC sublayer also prevents collision using protocols like CSMA/CD.
6. Header of a frame generally contains ______________
a) synchronization bytes
b) addresses
c) frame identifier
d) all of the mentioned
Explanation: In a frame, the header is a part of the data that contains all the required information about the transmission of the file. It contains information like synchronization bytes, addresses, frame identifier etc. It also contains error control information for reducing the errors in the transmitted frames.
7. Automatic repeat request error management mechanism is provided by ________
a) logical link control sublayer
b) media access control sublayer
c) network interface control sublayer
d) application access control sublayer
Explanation: The logical link control is a sublayer of data link layer whose main function is to manage traffic, flow and error control. The automatic repeat request error management mechanism is provided by the LLC when an error is found in the received frame at the receiver’s end to inform the sender to re-send the frame.
8. When 2 or more bits in a data unit has been changed during the transmission, the error is called ____________
a) random error
b) burst error
c) inverted error
d) double error
Explanation: When a single bit error occurs in a data, it is called single bit error. When more than a single bit of data is corrupted or has error, it is called burst error. If a single bit error occurs, the bit can be simply repaired by inverting it, but in case of a burst error, the sender has to send the frame again.
9. CRC stands for __________
a) cyclic redundancy check
b) code repeat check
c) code redundancy check
d) cyclic repeat check
Explanation: Cyclic redundancy check is a code that is added to a data which helps us to identify any error that occurred during the transmission of the data. CRC is only able to detect errors, not correct them. CRC is inserted in the frame trailer.
10. Which of the following is a data link protocol?
a) ethernet
b) point to point protocol
c) hdlc
d) all of the mentioned
Explanation: There are many data link layer protocols. Some of them are SDLC (synchronous data link protocol), HDLC (High level data link control), SLIP (serial line interface protocol), PPP (Point to point protocol) etc. These protocols are used to provide the logical link control function of the Data Link Layer.
Why Computer Network ?
The Linking Ballet: What's the Data Link Layer's Dance?
Imagine the Data Link Layer as the elegant choreographer, orchestrating a ballet of data between connected devices. It's the maestro of the networking stage, ensuring a harmonious performance.
"Data Link" Demystified: Beyond the Buzzwords
Before you drown in tech lingo, let's break it down. The Data Link Layer is like your networking BFF, making sure devices understand each other's language. It's the ultimate translator, keeping the conversation flowing.
Frame Fiesta: Data Link's Packaging Extravaganza
Ever wondered how your LOLcat pics make it across the digital seas? Thank the Data Link Layer's packaging prowess. It wraps your data into neat parcels, ready for the networking voyage.
MAC and Cheese: Meet the MAC Sublayer
MAC, not the one with cheese, but the Media Access Control sublayer. It's the bouncer at the networking club, deciding who gets to talk when. Think of it as the ultimate VIP list.
Device Duets: The Data Link Dance Partners
Now, envision the Data Link Layer as the dance floor, and your devices as its lively partners. Whether it's your laptop, smart fridge, or even your game console, they all tango with the Data Link Layer for a seamless networking performance.
In a Nutshell
The Data Link Layer is the unsung choreographer, the Fred Astaire of networking, ensuring your data dance is a showstopper. So, next time you click send, tip your hat to the backstage magician – the Data Link Layer! Happy networking, maestros!