Summary of "Functions of Application Layer | Application layer of OSI model in Hindi"
Summary of “Functions of Application Layer | Application layer of OSI model in Hindi”
Main Ideas and Concepts
1. OSI Model vs TCP/IP Model
- The OSI model consists of 7 layers:
- Application, Presentation, Session, Transport, Network, Data Link, Physical.
- The TCP/IP model has 4 layers:
- Application, Transport, Internet, Network Access.
- TCP/IP combines OSI’s Application, Presentation, and Session layers into a single Application layer.
- TCP/IP also merges OSI’s Data Link and Physical layers into the Network Access layer.
- Both models serve similar functions and protocols, but:
- OSI is theoretical.
- TCP/IP is practical and widely used.
2. Functions of the Application Layer (in TCP/IP model)
- Acts as an interface between users and the internet.
- Combines functionalities of OSI’s Application, Presentation, and Session layers:
- Application Layer: Connects users to the internet.
- Presentation Layer: Handles data formatting, translation, encryption/decryption, compression/decompression to ensure data is understandable.
- Session Layer: Manages sessions between sender and receiver — establishes, maintains, and terminates sessions during data transfer.
3. Important Protocols in the Application Layer
- DNS (Domain Name System):
- Maps domain names (e.g., facebook.com) to IP addresses.
- Uses TCP/UDP port 53.
- DHCP (Dynamic Host Configuration Protocol):
- Automatically assigns IP addresses to devices.
- Uses UDP ports 67 (server) and 68 (client).
- Replaced BOOTP.
- Email Protocols:
- SMTP (Simple Mail Transfer Protocol): For sending emails, uses TCP port 25.
- POP (Post Office Protocol): For receiving emails.
- IMAP (Internet Message Access Protocol): For managing and storing emails on the server.
- File Transfer Protocols:
- FTP (File Transfer Protocol): Uses TCP ports 20 (control) and 21 (data).
- TFTP (Trivial File Transfer Protocol): Uses UDP port 69; connectionless, faster but less reliable.
- HTTP/HTTPS:
- HTTP uses TCP port 80 for web browsing.
- HTTPS (secure HTTP) uses TCP port 443 with encryption for security.
4. Client-Server Communication Model
- Client: Requests services.
- Server: Provides services.
- Communication is request-response based.
- Servers usually have higher processing power and RAM to handle multiple requests.
- Multiple servers can exist in a network.
- The role of client or server depends on the software installed, not the physical device.
5. Peer-to-Peer (P2P) Model
- Devices act both as client and server simultaneously.
- Each device can provide and consume services.
- Suitable for small networks.
- P2P is less common in large networks due to complexity and potential failures.
Detailed Bullet Points
-
OSI vs TCP/IP Model Layers:
- OSI: 7 layers.
- TCP/IP: 4 layers (Application combines OSI’s Application, Presentation, Session).
- Network Access layer combines OSI’s Data Link and Physical layers.
-
Application Layer Functions:
- Interface between user and internet.
- Data formatting and translation.
- Encryption and decryption.
- Compression and decompression.
- Session management (establish, maintain, terminate).
-
Protocols and Their Functions:
- DNS: Domain name to IP mapping, port 53.
- DHCP: Dynamic IP allocation, ports 67/68.
- SMTP: Sending emails, port 25.
- POP & IMAP: Receiving and managing emails.
- FTP: File transfer, ports 20 and 21.
- TFTP: Fast file transfer, UDP port 69.
- HTTP: Web browsing, port 80.
- HTTPS: Secure web browsing, port 443.
-
Client-Server Model:
- Client requests services.
- Server provides services.
- Server devices have more resources.
- Multiple servers can exist in one network.
- Role depends on software, not physical device.
-
Peer-to-Peer Model:
- Devices act as both client and server.
- Used in small networks.
- Not common in large networks.
- Devices are called peers.
Speakers/Sources Featured
- Primary Speaker: An unnamed Hindi-speaking instructor/presenter explaining networking concepts related to the Application layer and OSI/TCP-IP models.
- No other distinct speakers or external sources are identified.
Category
Educational