Posts

unit- 4 Transport Layer

Image
  TRANSPORT LAYER FUNCTIONS / SERVICES  The transport layer is located between the network layer and the application layer.  The transport layer is responsible for providing services to the application layer; it receives services from the network layer.  The services that can be provided by the transport layer are                 1. Process-to-Process Communication                  2.Addressing : Port Numbers                   3.Encapsulation and Decapsulation                   4.Multiplexing and Demultiplexing                   5.Flow Control                   6. Error Control                 ...

HTTP, FTP , REMOTE LOGIN

Image
  HTTP (HYPERTEXT TRANSFER PROTOCOL) - The Hyper Text Transfer Protocol (HTTP) is used to define how the client- server programs can be written to retrieve web pages from the Web. It is a protocol used to access the data on the World Wide Web (WWW). The HTTP protocol can be used to transfer the data in the form of plain text, hypertext, audio, video, and so on. HTTP is a stateless request/response protocol that governs client/server communication. An HTTP client sends a request; an HTTP server returns a response. The server uses the port number 80; the client uses a temporary port number. HTTP uses the services of TCP , a connection-oriented and reliable protocol. HTTP is a text-oriented protocol. It contains embedded URL known as links. How HTTP Works: Step-by-Step Process Here’s how HTTP works when you visit a website: Open Web Browser : First, you open your web browser and type a website URL (e.g.,  www.example.com ). DNS Lookup : Your browser asks a  Domain Name Sy...

Cryptography

Image
Cryptography Cryptography is a technique of securing information and communications using codes to ensure confidentiality, integrity and authentication. Thus, preventing unauthorized access to information. The prefix "crypt" means "hidden" and the suffix "graphy" means "writing". In Cryptography, the techniques that are used to protect information are obtained from mathematical concepts and a set of rule-based calculations known as algorithms to convert messages in ways that make it hard to decode them. Features Of Cryptography The features of cryptography that makes it a popular choice in various applications could be listed down as Confidentiality:  Information can only be accessed by the person for whom it is intended and no other person except him can access it. Non-repudiation:  The creator/sender of information cannot deny his intention to send information at a later stage. Integrity:  Information cannot be modified in storage or transition...