Functions and Protocols in the OSI Model

Functions and Protocols in the OSI Model

Application Layer
The protocols at the application layer handle the file transfers, virtual terminals, network management, fulfilling networking requests of applications.

1. FTP - File Transfer Protocol
2. TFTP - Trivial FTP
3. SNMP - Simple Network Management Protocol
4. SMTP - Simple Mail Transfer Protocol
5. Telnet
6. HTTP - Hypertext Transfer Protocol

Presentation Layer
The services of the presentation layer handle translation into standard formats, data compression and decompression, and data encryption and decryption.
No protocol work at this layer, just services. Presentation layer standards are as below :-

1. ASCII - American Standard Code for Information Interchange
2. EBCDIC - Extended Binary-Coded Decimal Interchange Mode
3. TIFF - Tagged Image File Format
4. JPEG - Joint Photographic Experts Group
5. MPEG - Motion Picture Experts Group
6. MIDI - Musical Instrument Digital Interface

Session Layer
The session layer protocols set up connections between applications; maintain dialog control; and negotiate, establish, maintain, and tear down the communication channel , Some of the protocols that work at this layer include

1. NetBIOS - Network Basic Input Output System
2. PAP - Password Authentication Protocol
3. PPTP - Point-to-Point Tunneling Protocol
4. RPC - Remote Procedure Call

Transport Layer
The protocols at the transport layer handle end-to-end transmission and segmentation of the data stream. 

1. TCP - Transmission Control Protocol
2. UDP - User Datagram Protocol
3. SPX - Sequenced Packet Exchange

Network Layer
The responsibilites of the network layer protocols include internetworking service, addressing, and routing.

1. IP - Internet Protocol
2. ICMP - Internet Control Message Protocol
3. IGMP - Internet Group Management Protocol
4. RIP - Routing Information Protocol
5. OSPF - Open Shortest Path First
6. IPX - Internetwork Packet Exchange

Data Link Layer
The protocols at the data link layer convert data into LAN or WAN frames for transmission and define how a computer access a network.
This layer is divided into the Logical Link Control (LLC) and the Media Access Control (MAC) sublayers.

1. ARP - Address Resolution Protocol
2. RARP - Reverse Address Resolution Protocol
3. PPP - Point-to-Point Protocol
4. SLIP - Serial Line Internet Protocol
5. IEEE 802.3 - Ethernet
6. IEEE 802.5 Token Ring
7. IEEE 802.11 - Wireless Ethernet

Physical Layer
Network interface cards and drivers convert bits into electrical signals and control the physical aspects of data transmission, including optical, electrical, and mechanical requirements.

1. RS/EIA/TIA-422, RS/EIA/TIA-423. RS/EIA/TIA-449, RS/EIA/TIA-485
2. 10Base-T, 10Base2, 10Base5, 100Base-TX, 100Base-FX, 100Base-T, 1000Base-T, 1000Base-SX
3. ISDN - Integrated Services Digital Network
4. DSL - Digital subscriber line
5. SONET - Synchronous Optical Networking