9000

Chapter 1 23

HP FDDI/9000 Resources

FDDI Concepts

Figure 1-2 FDDI Standards and the OSI Model

The physical layer includes two pieces, the Physical Medium

Dependent (PMD) layer that provides the point-to-point

communications between stations in the network, and the Physical

Layer Protocol (PHY) layer that handles synchronization between

higher layer data and control symbols, and the code bit representation

which is transmitted on the medium.

The data link layer includes the Media Access Control (MAC)

standard and the Logical Link Control (LLC) standard. The MAC's

primary function is the scheduling, routing and delivery of Frames, the

vehicles used to transmit information on and off the ring. In an FDDI

network, information is transmitted sequentially, within frames, as a

stream of encoded symbols from one station to the next. The order of the

symbols within the frames is predetermined by the MAC standard. The

LLC provides a common protocol between the MAC and the network

layer. In addition to FDDI, the LLC standard also applies to IEEE 802.3,

802.4, and 802.5 networks.

Application

Presentation

Session

Transport

Network

Data Link

Physical

802.2 Logical Link Control (LLC)

Media Access Control (MAC)

Physical Layer Protocol (PHY)

Station Management

ISO 8802-2:1989 IEEE 802.2-1981

ISO 9314-2:1989

ANSI X3.139-1987

ISO 9314-1:1989

ANSI X3.148-1988

Physical Medium Department (PMD)

ISO 9314-3:1990

ANSI X3.166-1990

ISO to be determined

ANSI X3T9.5/84-49

Revision 7.3