The OSI Model with possible protocols

7

Application

Provides services directly to user applications.
Identifies communication partners, identifies quality of service, considers user authentication and privacy and determines if adequate ressources are present.

Gateway

SMB
HTTP
SMTP
FTP
SNMP
Telnet
AppleTalk

6

Presentation

Performs data transformations and services including formatting, compression and encryption services to provide a common interface for user applications.

Gateway
Redirectors

HTTP
FTP
Telnet
SMTP
AFP
TDI

5

Session

Establishes, manages and terminates connections between applications at each end.
Allows 2 applications to communicate over a network by opening a sessions and synchronizing the involved computers.

Gateway

NetBEUI
TCP
UDP
SPX

4

Transport

Provides transparent transfer of data between end systems by insulating layers 5-7 from complexities of layers 1-3.
Responsible for end to end error recovery and flow control and ensures complete data transfer.

Gateway

IP
IPX
NWLink
NetBEUI

3

Network

Establishes, maintains and terminates network connections.
Handles traffic management including addressing, routing, switching, forwarding, local paths and virtual circuits, error handling, congestion control and packet sequencing.

Router
Brouter

IP
IPX
NWLink
NetBEUI

2

Data Link

Divided into two sub-layers:
The Media Access Control (MAC) sub layer controls how a networked computer gains access to the data and permission to transmit it
The Logical Link Control (LLC) sub layer controls frame synchronization, flow control and error checking.

Switch
Bridge
Router

Ethernet
PPP
HDLC

1

Physical

Controls transmission of the bit stream data over the physical medium.
Standards for this layer address transmission at the electrical and menchanical level including signal voltage swing, voltage duration, etc.

Multiplexer
Repeater

Ethernet
Token Ring
FDDI