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Quiz on Application Layer

Quiz on Application Layer

By Trapti Gupta
9 mins read
Last updated: 4 May 2023
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Introduction to the Application Layer

In the OSI(Open System Interconnection) model, the layer which is the closest layer to the user is the application this means that there is a direct interaction between the user and the application layer. Application is the topmost and seventh layer of the OSI model. The presentation layer is the layer just below the application layer in the OSI model and the application layer receives various information sent by the presentation layer. There is a direct interaction between the application and application layer interface for providing web application services. Functions of the Application layer

  • Files accessing and transferring
  • Email transmission
  • Directories and network access

Basic Application Layer Questions (MCQ)

Application Layer is Which Layer of the OSI Model?

  • a) the fifth layer
  • b) the seventh layer
  • c) the first layer
  • d) the second layer

Answer - b: The application layer is the seventh layer of the OSI model.

Explanation:

OSI model provides us with seven layers for communication between devices connected through the network. And the seven layers of the OSI model are the Physical Layer, Data Link Layer, Network Layer, Transport Layer, Session Layer, Presentation Layer, and Application Layer. Refer to the below image for the layers of the OSI model

Which of the Following is Not the Protocol of the Application Layer?

  • a) POP3
  • b) HTTP
  • c) IMAP
  • d) TCP

Answer - d: TCP is not the application layer protocol

Explanation:

POP3(Post Office Protocol version 3), HTTP(HyperText Transfer Protocol), and IMAP(Internet Messaging Access Protocol) are the application layer protocols. Transmission Control Protocol is abbreviated as TCP and it is not an application layer but it is a transport layer protocol and it is a connection-oriented protocol for the transmission of data.

What is the Full Form of FTP?

  • a) Folder Transfer Protocol
  • b) Find That Pigeon
  • c) File Transfer Protocol
  • d) File Transmission Protocol

Answer - c: FTP stands for File Transfer Protocol

Explanation:

File Transfer Protocol is abbreviated as FTP and it is an application layer protocol that defines the rules for the transmission of files between network devices such as laptops, personal computers, etc.

Which of the Following Layers is Below the Application Layer in the OSI Model?

  • a) Internetworking
  • b) Transport
  • c) Presentation Layer
  • d) Network layer

Answer - c: Presentation layer is below the application layer in the OSI model.

Explanation:

There are seven layers in the OSI model for the interaction between devices over the network. These seven layers are the Physical Layer, Data Link Layer, Network Layer, Transport Layer, Session Layer, Presentation Layer, and Application Layer.

Refer to the below image for the layers of the OSI model

Which of the Following is the Full Form of the SMTP

  • a) Simple Mailman Trail Protocol
  • b) Simple Mail Transfer Protocol
  • c) Simple Messaging Transferal Protocol
  • d) Simplified Mail Transfer Protocol

Answer - b: SMTP stands for Simple Mail Transfer Protocol

Explanation:

Simple Mail Transfer Protocol is abbreviated as SMTP and it is an application layer protocol that is used for the transmission of emails between devices such as mobile, laptop, etc. over the internet.

Which of the Following Represents the Full Form of the HTTP?

  • a) Hypertext Transfer Protocol
  • b) Hypertext Transferal Protocol
  • c) Hyper-Transfer Protocol
  • d) Hypertext Transfer Protocol Secure

Answer - a: HTTP stands for Hypertext Transfer Protocol

Explanation:

Hypertext Transfer Protocol is abbreviated as HTTP and it is an application layer protocol that allows loading of the web pages with the help of Hypertext links. HTTP is a protocol designed for web server and web browser communication but it can be used for many other different purposes.

Intermediate Application layer questions(MCQ)

Which of the Following Option Appropriately Represents the Difference Between HTTP and HTTPS

  • a) Encryption is used by HTTPS
  • b) There is a level of data protection in HTTPS
  • c) HTTPS is an application while HTTP is one of the theoretical models.
  • d) HTTPS can be used in Wifi networks only

Answer - a: Encryption is used by HTTPS

Explanation:

The full form of HTTP is Hyper Text Transfer Protocol and the full form of HTTPS is Hyper Text Transfer Protocol Secure. HTTPS is the secure version of the HTTPS which is provided with the features of encryption and verification. HTTP transmits data in the form of plain text while in HTTPS data is transmitted in the form of cipher text i.e. encrypted form. SSL(Secure Socket Layer) is used by the HTTPS for http request and response encryption and HTTPS also signs the request and response digitally.

What is the Difference Between SMTP and POP3

  • a) Both protocols are operated in the same way.
  • b) E-mails are transmitted from clients to servers by the POP3
  • c) E-mails are transmitted from clients to servers by the SMTP
  • d) POP3 is the newer version of the mail transfer protocol while SMTP is the older version of POP3

Answer - c: E-mails are transmitted from clients to servers by the SMTP

Explanation:

SMTP stands for Simple Mail Transfer Protocol and it is a push protocol it is responsible for the transmission of mail from the mailbox of the sender to the mailbox of the receiver. POP3 stands for Post Office Protocol version 3 and it is a pop protocol used for retrieving and organizing the mail from the mail server of the receiver to the receiver's device.

"404" Status Code of HTTP Means?

  • a) Document has moved
  • b) Protocol error
  • c) Successful document retrieval
  • d) Document not found

Answer - d: Status code "404" of HTTP means Document not found

Explanation:

HTTP 404 status code means that the resource requested by the user is not founded by the server and it only represents that the resource is missing it does not provide any information on whether the absence of the resource is temporary or permanent.

Example:

Suppose we are requesting the URL https://www.scaler.com/I-do-not-exist/, and there is no content for this page. So here error code "404" is displayed as no page exists for the requested URL.

Which of the Following Application Layer is used for the Retrieval of the Mail?

  • a) RFC
  • b) IMAP
  • c) ICANN
  • d) HTML

Answer - b: IMAP protocol is used for retrieving the mail.

Explanation:

Internet Message Access Protocol is abbreviated as IMAP and it is an application layer protocol that enables the user for accessing the mail from the mail server.

2 Mail Transfer Protocols of the Application Layer are:

  • a) SMTP and POP
  • b) FTP and SMTP
  • c) TCP and FTP
  • d) POP and IP

Answer - a: SMTP and POP protocols are the two mail transfer protocols.

Explanation:

SMTP stands for Simple Mail Transfer Protocol and it is a push protocol used for sending mail and POP3 stands for Post Office Protocol version 3 and it is a pop protocol used for accessing the mail.

Advanced Application Layer Questions(MCQ)

Example(s) of Stateful Application Layer Protocols is/are

  • (i) TCP
  • (ii) FTP
  • (iii) HTTP
  • (iv) POP3
  • a) (i) and (ii) only
  • b) (ii) and (iii) only
  • c) (ii) and (iv) only
  • d) (iv) only

Answer - a: TCP and FTP protocols are the stateful application layer protocols.

Explanation:

In a computer network, stateful protocols are those protocols that send to the server and expect the response for the sent request and if the response is not received then it resends the request to the server. Some examples of stateful application layer protocols are: TCP(Transmission Control Protocol), FTP(File Transfer Protocol)

Correct Order of the Process of Interaction Between the Web Server and Web Browser is

  1. Web page is requested by the web browser using HTTP.
  2. TCP connection is established by the web browser to the web server.
  3. Requested webpage is sent back to the web browser using the HTTP.
  4. Domain name is resolved by the web browser using the DNS(Domain Name System).
  • a) 4,2,1,3
  • b) 1,2,3,4
  • c) 4,1,2,3
  • d) 2,4,1,3

Answer - a: 4,2,1,3 is the correct order of the interaction between the web server and the web browser.

Explanation:

First of all DNS(Domain Name System) is used by the web browser for figuring out the IP address of the URL entered, and then there is the establishment of the TCP connection between the web server and the web browser. The TCP connection is generally created at port no 80. After the TCP connection establishment HTTP request is sent by the web browser by using the GET. And at last web server sends the response to the request sent by the web browser through the HTTP response.

  • a1: Transmission of the mail from the client of the mail to the server of the mail.
  • a2: Email downloading from the mailbox server to the client of the mail
  • a3: Checking of the email in a web browser Tell the appropriate application layer protocol used for the above mail transmission activities
  • a) a1: HTTP a2: SMTP a3: POP
  • b) a1: SMTP a2: FTP a3: HTTP
  • c) a1: SMTP a2: POP a3: HTTP
  • d) a1: POP a2: SMTP a3: IMAP

Answer - c: SMTP protocol is used for activity1, FTP is used for activity2 and HTTP is used for activity3. Explanation: Simple Mail Transfer Protocol (SMTP) is used by clients for sending mail to the mail server. Client use Post Office Protocol (POP) for receiving emails. Checking the mail in the web browser is simply the HTTP process.

Which of the Following UNIX Command is used to Check Whether any Particular Host is Reachable or not?

  • a) ftp
  • b) telnet
  • c) traceroute
  • d) ping

Answer - d) ping command is used for checking whether that particular host is reachable or not.

Explanation:

ping is a networking command that enables checking and verifying whether there is a connection with a particular destination address or not over the network. Syntax:

ping [ -d] [ -D ] [ -n ] [ -q ] [ -r] [ -v] [ -R ] [ -a addr_family ] [ -c Count ] [ -w timeout ] [ -f | -i Wait ] [ -l Preload ] [ -p Pattern ] [ -s PacketSize ] [ -S hostname/IP addr ] [ -L ] [ - I a.b.c.d. ] [ -o interface ] [ -T ttl ] Host [ PacketSize ] [ Count ]

In the TCP/IP Model, for the Application Layer Which of the Following is the Protocol Data Unit (PDU)

  • a) Segment
  • b) Datagram
  • c) Message
  • d) Frame

Answer - c) message is the PDU for the application layer in the TCP/IP model.

Explanation:

The bit is the PDU for the Layer 1 i.e. Physical Layer The frame is the PDU for the Layer 2 i.e. Data Link Layer Packet if the PDU for the Layer 3 i.e. Network Layer For the fourth Layer i.e. Transport Layer, the segment is the PDU for the TCP and the Datagram is the PDU for the UDP Message or Data is the PDU for the Layer 5 i.e. Application Layer