Data Link Layer MCQ Quiz in తెలుగు - Objective Question with Answer for Data Link Layer - ముఫ్త్ [PDF] డౌన్‌లోడ్ కరెన్

Concept:

OSI model is a layered framework for the design of network systems that allows communication between all types of computer systems. It consists of seven layers but related layers each of which defines a part of the process of moving information across a network.

Explanation:

The seven layers from bottom to top are as follows: physical layer, data link layer, network layer, transport layer, session layer, presentation layer, application layer.

But here we have to focus only on data link layer and network layer.

Data link layer:

This layer is responsible for moving frames from one hop to next. Data link layer divides the stream of bits received from the network layer into manageable units called frames. It adds a header to the frame to define the sender and receiver of the frame. It provides a flow and error control mechanism.

Network layer:

It is responsible for the delivery of individual packets from source host to the destination host. When two systems are attached to different networks with connecting devices between them, there is a need for the network layer to accomplish source to destination delivery of packets. Smallest unit of data that is transmitted is known as packet in network layer.

Concepts:

An Ethernet Switch is a LAN interconnection device which operates at the data link layer (layer 2) of the OSI reference model.

A switch is fundamentally similar to a bridge, but usually supports a larger number of connected LAN segments and has a richer management capability.

Number of machines = 15

In a LAN, Ethernet switches is having 8 port

Diagram:

Therefore, number of switches is 3

• A point-to-point connection provides a dedicated link between two devices
• In mesh, star and ring topologies are a point-to-point connection
• In a star topology, each device needs only one link and one I/O port to connect it to any number of other devices
• In a ring topology, each device has a dedicated point-to-point connection with only the two devices on either side of it; Each device is connected to its corresponding repeater
• In a mesh topology, every device has a dedicated point-to-point link to every other device
• A multipoint connection is one in which more than two specific devices share a single link
• In Bus Topology, one long cable acts as a backbone to link all the devices in a network

The Internet Protocol (IP) is the transmission mechanism used by the TCP/IP protocols. IP transports data in packets called datagrams, each of which is transported separately. Datagrams can travel along different routes and can arrive out of sequence or be duplicated.

The correct answer is Physical Layer

The correct answer is Internal links.

Key Points

• Internal Link
  • An internal link is any link from one page on your website to another page on your website. 
  • Both your users and search engines use links to find content on your website. 
  • Your users use links to navigate through your site and to find the content they want to find. Search engines also use links to navigate your site. 
  • They won’t find a page if there are no links to it.
  • There are several types of internal links. 
  • In addition to links on your homepage, menu, post feed, etc, you can also add links within your content. 
  • Internal links only point within your own specific website or domain. Hence, Option 4 is correct.
  • The menu bar at the top of your site includes internal links. 
  • Links from pages on your site to your contact page are another simple example of internal links.
  • We call those contextual links. Contextual links point your users to interesting and related content. Moreover, they allow search engines to find out what content on your site is related and to determine the value of that content. 
  • The more links an important page receives, the more important it will seem to search engines. Therefore, good internal links are crucial to your SEO.

Additional Information

• External links 
  • External links point from one domain to an entirely separate domain. 
  • They may be links from your website to another website to provide additional information for readers, or they may be links from your website to an affiliate program. 
  • Links from other sites into yours can also be called external links, although the preferred term is “inbound” links, to distinguish them from links you’ve added to your own site that connect to other sites.
• URL
  • It is the short form for Uniform Resource Locator, a website URL is the location of a specific website, page, or file on the Internet.
  • Every URL is made up of multiple parts, and the way yours are built will have a variety of effects on your site’s security and Search Engine Optimization (SEO).
• Text link
  • A text associated with a link target is described as a link text.
  • This can be a word, a character, or even several words up to (theoretically) several sentences.
  • The clickable link text associated with a URL is then described as a hyperlink.
  • Synonyms for link text also include anchor text or reference text.

Data:

Bandwidth = 100 Mbps

Propagation delay = 20 µsec

Packet size = 10000 bits

Packet 1 size = 5000 bits

Calculation:

Packet 1:

Transmission time = \(\frac{{{5000}}}{{{{10}^8}}}\) = 50 µsec

Total transmission time = 2 × 50 + 2 × 20 + 35 = 175 µsec

When sending them as two packets, time to transmit one packet is half.

It happens in the order as :

T =0   start

T = 50 A finishes sending packet 1, starts packet 2

T = 70 packets 1 finishes arriving at S

T = 105 packet 1 departs for B

T = 100 A finishes sending packet 2

T = 155 packet 2 departs for B

T = 175 bit 1 of the packet arrives at B

T = 225 last bit of packet 2 arrives at B

As, when packet 1 starts to make its way through the switch while packet 2 is still being transmitted on the first link, getting a 50 µsec head start. So, this time is 50 less than the total time.

Tips and Tricks:
Since the second packet start from 50 µsec

Transisstion of 2nd packet = 175 µsec + start time = 225 µsec

Reading MAC address form left to right:

Unicast MAC address: Least significant bit (LSB) of 1st byte is 0

2A : 1F : 41 : 4C : 11:19

1st byte = 2A = 0010 1010

Multicast MAC address: Least significant bit (MSB) of 1st byte is 1

1B : 3A : 23 : 7F : 32 : 1F

1st byte = 1B = 0001 1011

C9 : EA : B2 : 1D : 64 : 15

1st byte = C9 = 1100 1001

Broadcast MAC address: All bits are 1

 FF : FF : FF : FF : FF : FF

1st byte = FF = 1111 1111 (also multicast MAC address)

Note:

Every Broadcast MAC address is also a Multicast MAC address

Concept:

Bit stuffing is a method used in communication protocols (such as HDLC) to ensure that special delimiter patterns (e.g., 01111110 in this case) don't accidentally appear in the data stream. If a sequence of five consecutive 1s appears in the data, a `0` is inserted automatically after the five 1s. This ensures that the delimiter pattern (which also contains five consecutive 1s) does not occur in the transmitted data.

Given Information:

• Delimiter pattern: `01111110`
• Stuffed output bitstring: `01111100101`

Bit Unstuffing Process:

• To recover the original data from the bitstuffed string, we need to reverse the bitstuffing process by removing any `0` that follows five consecutive `1`s.

1. Identify the stuffed sequence: 

• In the given bitstring, 01111100, the sequence `011111` contains five consecutive 1s.
• The `0` that follows is a stuffed bit that was inserted to avoid confusion with the delimiter pattern.

2. Remove the stuffed bit:

• We need to remove the `0` that was inserted after five consecutive 1s.
• After removing the stuffed bit, the bitstring becomes `0111110101`.

3. Reconstruct the original bitstring:

• The original bitstring before stuffing is 0111110101.

Validation:

• The original bitstring contains the sequence `011111`, but it doesn't have six consecutive 1s, so it did not need to be stuffed.
• After the bitstuffing protocol was applied, a `0` was inserted after the five consecutive 1s, resulting in the stuffed bitstring 01111100101.

The original bitstring before stuffing was: 2) 0111110101.

Data link layer performs framing, error control and flow control

Physical layer performs channel coding.