The Application Layer

Main objective of this lecture is to explain on the Application Layer. General portion of Application Layer is DNS –Domain Name System; here focus on the DNS Name Space, Resource Records and Name Servers. This lecture also describe on Electronic Mail: Architecture and Services, the User Agent, Message Formats, Message Transfer and Final Delivery. Finally discuss on Multipurpose Internet Mail Extensions, Architectural Overview, the Server Side and URLs (Uniform Resource Locators).