Code360 powered by Coding Ninjas X Code360 powered by Coding Ninjas X
Table of contents
Frequently Asked Questions
Last Updated: Mar 27, 2024

Transport Layer

Master Python: Predicting weather forecasts
Ashwin Goyal
Product Manager @


The transport layer allows application processes on various hosts to communicate logically. Although application processes on different hosts are not physically connected, they use the transport layer's logical communication to transmit messages to one another.

Refer to this link to learn more about Transport Layer.


Now, we will see gate questions on Transport Layer with their solutions and explanations.

  1. The size of the congestion window during the slow start phase of the TCP congestion control algorithm

    a. does not increase
    b. increases quadratically
    c. increases linearly
    d. increases exponentially

    Ans: d

    Explanation: Despite the name, the window size is raised by the number of segments acknowledged during the sluggish start phase, which means the window size rises exponentially. This will continue until a segment acknowledgment is received or a preset threshold value is reached.
  2. Electronic mail is supported by which of the following transport layer protocols?

    a. SMTP
    b. TCP
    c. IC
    d. UDP 

    Ans: b

    Explanation: The application layer protocol for e-mail is SMTP. Two transport layer protocols are TCP and UDP. TCP is used by SMTP because it is reliable.
  3. Which of the following is a transport protocol that uses UDP?

    a. HTTP
    b. Telnet
    c. DNS
    d. SMTP

    Ans: c

    Explanation: UDP is a connectionless, stateless, and unreliable protocol.
    TCP is used because HTTP requires the establishment of a connection.
    Telnet is a byte stream protocol that requires the establishment of a connection. Hence it employs TCP.
    DNS requires request and response and a protocol that allows a server to respond to small inquiries from a large number of users. UDP is the most appropriate protocol for DNS queries because it is fast and stateless.
    Since SMTP requires reliability, it employs TCP.
  4. The transmission rate of this TDM's circuit if the link transmits 4000 frames per second and each slot has 8 bits is:

    a. 32 Mbps
    b. 64 Kbps 
    c. 32 Kbps
    d. 64 Mbps

    Ans: c

    Explanation: Transmission rate equals frame rate multiplied by the number of bits in a slot. TDM = 4000 * 8 bps = 32 Kbps Frame rate = 4000 frames per second, number of bits in a slot = 8 bit As a result, option (C) is the correct answer.
  5. Which procedure is used to shape bursty traffic into fixed-rate traffic by averaging the data rate?

    a. hocken helm algorithm
    b. spanning-tree algorithm
    c. solid bucket algorithm
    d. leaky bucket algorithm

    Ans: d

    Explanation: A leaky bucket algorithm is a form of congestion control that regulates the average data flow rate while checking on data flow. Option (D) is the correct answer.
  6. In the internet stack, the protocol data unit for the transport layer is

    a. segment
    b. datagram
    c. message
    d. frame

    Ans: a

    Explanation: When TCP is used, the protocol data unit for the transport layer in the internet stack is Segment, and when UDP is used, the protocol data unit is Datagram. Protocol data units for other layers are Layer of the Network: Packet Frame DataLink Layer Stream Physical Layer Message Option (A) in the Application Layer is correct.
  7. The TCP sliding window

    a. can be used to control the flow of information
    b. occurs horizontally
    c. always occurs when the field value is 0
    d. always occurs when the field value is 1

    Ans: a

    Explanation: The Sliding Window method is used by TCP to manage the flow of data in transit on a network. The sender device can send all packets within the TCP window size without receiving an ACK in Sliding Window. The receiving device should acknowledge each packet it receives, and the sending device should slide the window to the right side after receiving the ACK from the receiving device. As a result, option (A) is the correct answer.
  8. Which of the following statements are correct

    (S1) TCP is in charge of both congestion and flow control 
    (S2) UDP is in charge of congestion but not flow control
    (S3) Slow start method deals with both congestion and flow control 
    (S4) Fast re-transmit deals with congestion but not flow control.

    a. s1,s2,s3
    b. s1,s3
    c. s3,s4
    d. s1,s2,s4

    Ans: b

    Explanation: 1: Using the TCP window for flow control and the congestion window for congestion control.
    2: There are no fields in the UDP header that control flow or congestion.
    3: TCP utilizes it to re-transmit out-of-order segments to solve the problem.
    4: Slow start, unrelated to flow control
  9. Which of the following OSI Reference model layers is also known as the end-to-end layer

    a. Network layer
    b. Data layer
    c. Session layer
    d. Transport layer

    Ans: d

    Explanation: The transport layer in the OSI model is in charge of end-to-end communication. 
  10. Assume you're using a web browser to browse the internet and trying to connect to web servers. What are the underlying protocol and the port number that is being used?

    a. UDP, 80
    b. TCP, 80
    c. TCP, 25
    d. UDP, 25

    Ans: b

    Explanation: TCP is used for connection-based data communication and transfer. A TCP connection is required for a browser to connect and access web servers, and it operates on the well-defined port number 80. 

We will close the article now with faqs since you get some idea of the gate questions of the transport layer.

Also, Read - Demultiplexer

Get the tech career you deserve, faster!
Connect with our expert counsellors to understand how to hack your way to success
User rating 4.7/5
1:1 doubt support
95% placement record
Akash Pal
Senior Software Engineer
326% Hike After Job Bootcamp
Himanshu Gusain
Programmer Analyst
32 LPA After Job Bootcamp
After Job

Frequently Asked Questions

  1. What is the transport layer?
    The Transport Layer is the fourth layer of the OSI Model. It allows data to be sent between end-users transparently while also delivering dependable data transfer services to the upper layers.
  2. What is the main function of the transport layer?
    The Transport layer's fundamental role is to collect data from the session layer, split it up into smaller units if necessary, transfer it to the Network layer, and verify that all pieces reach the other end successfully.
  3. What is meant by transport layer demultiplexing?
    Taking data from one socket (potentially several), wrapping a data chuck with header information to create a transport layer segment, and then transferring this Segment to the network layer is called demultiplexing.
  4. How does the transport layer help in flow control?
    The transport layer of the TCP/IP paradigm provides a flow control mechanism between the adjacent layers. TCP also employs flow control techniques to prevent data loss caused by a fast transmitter and a slow receiver.
  5. What is the difference between TCP and UDP?
    UDP is a connectionless protocol, whereas TCP is a connection-oriented protocol. TCP is slower than UDP, one of the main differences between the two protocols. Overall, UDP is a much faster, simpler, and more efficient protocol, yet, only TCP allows for the retransmission of lost data packets.


This article extensively discussed various GATE questions on Transport Layer. This article covers the solution and explanation of these GATE questions.

Refer to this link to learn more about Transport Layer in detail.
Check out this problem - No of Spanning Trees in a Graph

We hope that this blog helped you improve your knowledge regarding the Application layer, and in case you like to learn more, check our articles in the code studio library. Do upvote our blog to help other ninjas grow. Happy Coding!

Previous article
Network Layer
Next article
Hamming Code in Computer Networks
Live masterclass