Need some edits here too much useless info

1. Overview

• Definition: Closest OSI layer to the end user. Directly interacts with application software.
• Purpose: Enables process-to-process communication using protocols like DNS, FTP, HTTP, etc.
• Architecture: Based on client–server model.

2. Functions of Application Layer

1. Identifying Communication Partners – Finds available hosts for communication.
2. Determining Resource Availability – Checks if sufficient network resources exist.
3. Synchronizing Communication – Manages coordination between communicating applications.
4. Network Virtual Terminal – Allows login to a remote host via a virtual terminal.
5. File Transfer, Access, and Management (FTAM) – Remote file access, retrieval, and management.
6. Addressing – Uses DNS for mapping hostnames to IP addresses.
7. Mail Services – Enables email forwarding and storage.
8. Directory Services – Provides distributed databases for global service information.
9. Authentication – Validates sender and receiver identity.

3. Network Application Architecture

• Network Architecture: Fixed structure providing services to applications.
• Application Architecture: Designed by developers; defines app structure over end systems.