APPLICATION LAYER PROTOCOLS .pptx

APPLICATION LAYER PROTOCOLS .pptx

1. APPLICATION LAYER PROTOCOLS PRESENTED BY: Rolika Agarwal Shivi arora Shruti singh Flip class on the topic

2. Introduction: The application layer in the OSI model and TCP/IP model is the topmost and the closest layer to the end user which means that the application layer and end user can interact directly with the software application. The application layer programs are based on client and servers.

3. services OF APPLICATION LAYER Network Virtual terminal: A pplication layer allows a user to log on to a remote host. To do so, the application creates a software emulation of a terminal at the remote host. The user's computer talks to the software terminal, which in turn, talks to the host. The remote host thinks that it is communicating with one of its own terminals, so it allows the user to log on. File Transfer, Access, and Management (FTAM): A pplication layer allows a user to access files in a remote computer, to retrieve files from a computer and to manage files in a remote computer . Mail Services: A pplication layer provides the basis for E-mail forwarding and storage. Directory Services: An application contains a distributed database that provides access for global information about various objects and services.

4. Overview: application layer protocols The Application layer protocols in computer networks are a set of standards and rules that govern the communication between end-user applications over a network. These protocols provide a specific services and functionality to support different types of application-level communication, including file transfers, email, remote terminal connections, and web browsing. Some of the commonly used application layer protocols include: Hyper Text Transfer Protocol (HTTP) Hyper Text Transfer Protocol Secure (HTTPS) Domain Name System (DNS) File Transfer Protocol (FTP) Trivial File Transfer Protocol (TFTP) Simple Mail Transfer Protocol (SMTP) Post Office Protocol (POP3)

5. HyperText Transfer Protocol HTTP is an application-level protocol that is widely used for transmitting data over the internet. It is used by the World Wide Web, and it is the foundation of data communication for the web. This protocol is known as HyperText Transfer Protocol because of its efficiency that allows us to use in a hypertext environment where there are rapid jumps from one document to another document. HTTP works on client server model. When a user wants to access any HTTP page on the internet, the client machine at user end initiates a TCP connection to server on port 80. When the server accepts the client request, the client is authorized to access web pages. HTTP requests contain a method, a URI, and a set of headers, and they can also contain a payload, which is the data being sent. HTTP responses contain a status code, a set of headers, and a payload, which is the data being returned. HTTP is a connectionless stateless protocol, which means the The connection between client and server exist only during the current request and response time onlyand the server maintains no information about earlier requests by clients.

6. HyperText Transfer Protocol SECURE The  HTTP  protocol does not provide the security of the data, while HTTP ensures the security of the data. Therefore, we can say that HTTPS is a secure version of the HTTP protocol.  HTTPS is encrypted in order to increase security of data transfer. This is particularly important when users transmit sensitive data, such as by logging into a bank account, email service, or health insurance provider. In modern web browsers such as Chrome, websites that do not use HTTPS are marked differently than those that are. To provide encryption, HTTPS uses an encryption protocol known as Transport Layer Security, and officially, it is referred to as a Secure Sockets Layer (SSL). This protocol uses a mechanism known as asymmetric public key infrastructure, and it uses two different keys which are given below: Private key: This key is available on the web server, which is managed by the owner of a website. It decrypts the information which is encrypted by the public key. Public key: This key is available to everyone. It converts the data into an encrypted form.

7. Domain Name System DNS stands for "Domain Name System," and it is an essential component of the internet that translates domain names into IP addresses. A domain name is a human-readable string of characters, such as "google.com," that can be easily remembered, while an IP address is a set of numbers and dots that computers use to communicate with each other over the internet. The DNS system is a hierarchical, distributed database that maps domain names to IP addresses. When you enter a domain name into your web browser, your computer sends a query to a DNS server, which then returns the corresponding IP address. The browser can then use that IP address to send a request to the server hosting the website you’re trying to access. DNS has several benefits: It makes it possible for humans to access websites and other internet resources using easy-to-remember domain names, rather than having to remember IP addresses. It also allows website owners to change the IP address of their server without affecting the domain name, making it easier to maintain and update their website.

8. File Transfer Protocol FTP, or File Transfer Protocol, is a standard network protocol used for the transfer of files from one host to another over a TCP-based network, such as the Internet. It is widely used for transferring large files or groups of files, as well as for downloading software, music, and other digital content from the Internet. The systems involved in TCP-based network connections are heterogeneous, i.e. they differ in operating systems, directories, structures, character sets, etc the FTP shields the user from these differences and transfers data efficiently and reliably. FTP operates in a client-server architecture and has two communication channels, command channel for conversation control and data channel for file content, where a client establishes a connection to an FTP server and can then upload or download files from the server. The client and server exchange messages to initiate transfers, manage data transfers, and terminate the connection. It supports both active and passive modes, which determine the way the data connection is established between the client and the server.

9. Trivial File Transfer Protocol TFTP is defined as a protocol that is used to transfer a file from a client to a server and from a server to a client. It is majorly used when no complex interactions are required by the client and server. It is implemented on top of the UDP/IP protocols using well-known port number 69. TFTP does not provide security features ,therefore, it is not used in communications that take place over the Internet. It is used only for the systems that are set up on the L ocal A rea Networks(LANs) . TFTP requires less amount of memory and is intended for applications that do not need the sophisticated interactions that FTP provides. TFTP only reads and writes files from or to a remote server. It cannot list, delete, or rename files or directories and it has no provisions for user authentication.