Application Layer in Computer Networks part 1

Its Describes the how application layer and how its working in OSI Layer

1. Dr.S.BALAMURUGAN, Professor, Department of CSE,PMIST APPLICATION LAYER Discussion

2. key functions carried out by the application layer The Application Layer is responsible for providing network services to the user, including file transfer , email, remote login, and web browsing . Some common protocols that operate at the Application Layer include HTTP (Hypertext Transfer Protocol) FTP (File Transfer Protocol) SMTP (Simple Mail Transfer Protocol) POP3 (Post Office Protocol version 3)and DNS (Domain Name System). APPLICATION LAYER

3. FTP (File Transfer Protocol) FTP stands for File Transfer Protocol. It is a protocol used for transferring files over the internet between a client and a server. FTP can be used in a variety of contexts, such as transferring files between a user's computer and a web server , or between different servers. It is also commonly used for uploading and downloading files to and from a website. APPLICATION LAYER

4. HTTP (Hypertext Transfer Protocol) HTTP stands for Hypertext Transfer Protocol. It is a protocol used for transferring data over the internet , specifically for transmitting web pages and other resources from web servers to web browsers. APPLICATION LAYER

5. SMTP (Simple Mail Transfer Protocol) SMTP stands for Simple Mail Transfer Protocol. It is a protocol used for sending and receiving email messages over the internet APPLICATION LAYER

6. key functions carried out by the application layer POP3 stands for Post Office Protocol version 3. It is a protocol used for retrieving email messages from a mail server. APPLICATION LAYER

7. (Domain Name System)DNS DNS used to translate human-readable domain names, such as www.example.com, into IP addresses, such as 192.0.2.1, which are used by computers to communicate over the internet. When a user enters a domain name into their web browser, the browser sends a request to a DNS resolver to resolve the domain name into an IP address. The resolver then queries one or more DNS servers to find the IP address associated with the domain name. Once the IP address is obtained, the browser can establish a connection with the server associated with that IP address. APPLICATION LAYER

8. Network Services offered by the application layer File sharing: The ability to share files between devices on a network . This can be done through various protocols such as FTP, SMB, and NFS. Email: The ability to send and receive emails between devices on a network . This is usually done through an email server such as Gmail. Remote access: The ability to access network resources from remote locations . This can be done through VPNs or other remote access technologies. Web services: The ability to access web-based applications and services over a network. This includes services such as web hosting, webmail, and cloud computing. APPLICATION LAYER

9. Network Services offered by the application layer Voice over Internet Protocol (VoIP): The ability to make phone calls over a network using internet protocol . This includes services such as Skype, WhatsApp , and Zoom. Video conferencing: The ability to hold virtual meetings and video conferences over a network. This includes services such as Microsoft Teams, Zoom, and WebEx. Instant messaging: The ability to exchange text messages and chat in real-time between devices on a network . This includes services such as Microsoft Teams , Slack, and WhatsApp APPLICATION LAYER

10. MCQs 1. Which of the following protocols operates at the Application Layer? a) TCP b) SMTP c) IP d) ICMP Answer: b) SMTP

11. MCQs 2.Which of the following is not a function of the Application Layer? a) Providing network services to the user b) Providing standard communication protocols c) Facilitating communication between different applications on different devices d) Controlling the physical transmission of data over the network Answer: d) Controlling the physical transmission of data over the network

12. MCQs 3,Which of the following protocols is used for transferring files over the network? a) HTTP b) FTP c) SMTP d) DNS Answer: b) FTP

13. MCQs 4. Which of the following protocols is used for email communication? a) HTTP b) FTP c) SMTP d) DNS Answer: c) SMTP

14. MCQs 5.Which of the following layers of the OSI model is the Application Layer? a) Layer 1 b) Layer 2 c) Layer 3 d) Layer 7 Answer: d) Layer 7

15. MCQs 6.Which of the following is a web-based protocol used by browsers to access web pages? a) FTP b) SMTP c) HTTP d) Telnet

16. MCQs 7.Which protocol is used for converting domain names to IP addresses? a) FTP b) SMTP c) DNS d) Telnet Answer: c) DNS

17. MCQs 8.Which of the following protocols is used for remote login? a) FTP b) SMTP c) Telnet d) HTTP Answer: c) Telnet Telnet allows a user to connect to a remote computer and access its command-line interface. Telnet sends all data in plain text, including usernames and passwords. No Encryption mechanism. Secure Shell, is a secure protocol, It is commonly used for remote login. All data transmitted between the two computers is encrypted.

18. MCQs 9.Which of the following protocols is used for secure web browsing? a) HTTP b) HTTPS c) FTP d) Telnet Answer: b) HTTPS Hypertext Transfer Protocol Secure, is a secure version of the HTTP protocol. HTTPS is commonly used for transmitting sensitive information over the internet, such as passwords, credit card details, and other personal information. It is widely used by e-commerce websites, banking websites, and other sites that require secure transmission of data.

19. MCQs 10.Which protocol is used for sending and receiving email messages? a) HTTP b) FTP c) SMTP d) DNS Answer: c) SMTP

20. key functions carried out by the application layer The Application Layer is responsible for providing network services to the user, including file transfer , email, remote login, and web browsing . Some common protocols that operate at the Application Layer include HTTP (Hypertext Transfer Protocol) FTP (File Transfer Protocol) SMTP (Simple Mail Transfer Protocol) POP3 (Post Office Protocol version 3)and DNS (Domain Name System). APPLICATION LAYER

21. Link-state routing is a type of routing protocol used in computer networks to determine the optimal path for data to travel from one device to another. In link-state routing, each device maintains a detailed map of the network topology, including the status of each link and the location of other devices. In link-state routing, each device makes independent decisions about the best path to take based on its own map of the network topology . This allows for greater efficiency and flexibility in choosing the optimal path for data to travel, and can lead to faster and more reliable communication in the network. Link state routing