Application Provides a set of interfaces for applications to use to AFP,FTP Gateway

gain access to networked services. NCP,SMTP

SNMP

Presentation Converts data into a generic format for network Gateway

transmission; for incoming messages, it converts

data from this format into a format that the receiving

application can understand.

Session Enables two parties to hold ongoing communications Gateway

-called sessions-across a network.

Transport Manages the transmission of data across a network. TCP, SPX, Gateway

NWLINK

NetBEUI

Network Handles addressing messages for delivery, as well as IP, IPX Routers

translates logical network addresses and names into Brouter

their physical counterparts.

Data Link Sends special data frames from the Network layer to Bridges

the Physical layer.

Physical Converts bits into signals for outgoing messages, and Repeaters,

signals into bits for incoming messages. Amplifiers

Hubs

Routable Protocols: DECnet, IP, IPX/SPX, OSI, XNS, DDP(appletalk)

Non-Routable Protocols: NetBEUI, LAT, DLC