Open System Interconnection (2)
(1) Physical: passes bit stream between computer and network; defines voltage used, the data transmission timing, handshaking requirements; EIA-RS232, RS449, Ethernet, token ring, FDDI
(2) Data Link: provides reliable data transfer between computer and network; packages data into data frames; HDSL, SDSL, ATM, FR, NDIS, ODI
(3) Network: sets up and maintains connections; establishes virtual circuits between computers; IP, X.25, IPX
(4) Transport: provides control of quality of service; TCP, UDP, SPX, NetBEUI