| OSI Layer | Layer Number | Protocols/Technologies | TCP/IP Model Layer |
|---|---|---|---|
| Application | Layer 7 | HTTP, FTP, SMTP, SNMP, DNS, Telnet, SSH, POP3, IMAP, NTP, DHCP | Application |
| Presentation | Layer 6 | SSL/TLS, JPEG, MPEG, GIF, TIFF, ASCII, EBCDIC | Application |
| Session | Layer 5 | NetBIOS, RPC, PPTP, PAP, NFS, SQL, SMB | Application |
| Transport | Layer 4 | TCP, UDP, SCTP, DCCP | Host-to-Host |
| Network | Layer 3 | IP, ICMP, ARP, RARP, BGP, OSPF, RIP, IPsec, IGMP | Internet |
| Data Link | Layer 2 | Ethernet, PPP, HDLC, Frame Relay, ATM, MPLS, L2TP, ARP | Network Access |
| Physical | Layer 1 | USB, DSL, ISDN, Bluetooth, 802.11, Ethernet (Cabling), FDDI | Network Access |
This table shows how different protocols function within specific layers of the OSI and TCP/IP models, providing a clear overview of network communication processes.
Layer Details:
- Application (OSI Layer 7 / TCP/IP Application Layer): Handles network applications and end-user processes.
- Presentation (OSI Layer 6 / TCP/IP Application Layer): Translates data formats, encryption, and compression.
- Session (OSI Layer 5 / TCP/IP Application Layer): Manages sessions between applications.
- Transport (OSI Layer 4 / TCP/IP Host-to-Host Layer): Ensures reliable data transfer and error correction.
- Network (OSI Layer 3 / TCP/IP Internet Layer): Manages logical addressing and routing.
- Data Link (OSI Layer 2 / TCP/IP Network Access Layer): Handles physical addressing and error detection.
- Physical (OSI Layer 1 / TCP/IP Network Access Layer): Manages the physical transmission of data.
These protocols are crucial for maintaining secure communication channels in various networked environments, especially when managing remote systems.
- TELNET
- Function: Provides remote terminal access, allowing users to log in to remote servers and control them via a command line.
- Security: Originally not secure, but secure versions of Telnet are available that enhance security by encrypting the communication.
- Remote Procedure Call (RPC)
- Function: Enables programs to execute procedures on other machines in a network as if they were local.
- Security: Secure Remote Procedure Call (SRA) is used to secure the communication by ensuring that the data exchanged during the procedure calls is protected.
- SSH (Secure Shell)
- Function: A secure alternative to Telnet, SSH provides encrypted communication for remote server administration via the command line.
- Security: SSH encrypts the session, ensuring that both authentication and data exchange are secure.