Sun Microsystems 1.0 - Manual (Page 79)

FDDI Network Architecture 53
6
At its lowest level, the SMT protocol handles connection management ( CMT ). This
includes station initialization, the insertion and removal of stations on the
network, and connection compatibility between stations. At a higher level, the
SMT protocol handles ring management (RMT). This includes the detection of
duplicate addresses and the isolation of fault conditions.
The SMT protocol also defines the FDDI management information base (MIB).
This is a set of managed objects and associated attributes that includes the
MAC entity (MAC), data path (PATH), attachment type (ATTACHMENT), and
port identifier (PORT).
Communication services are used to exchange objects and information between
peer SMT entities through special management frames that are carried at the
same time as normal network traffic. This frame-based management is used to:
•
Examine and modify FDDI station configuration
•
Schedule synchronous (guaranteed) and asynchronous (priority-based)
traffic
•
Gather network statistics
• Generate status reports
SunFDDI/P includes SunNet Manager agents that access the SMT entity to
collect and return FDDI statistics to a SunNet Manager console. See Chapter 9,
“Managing FDDI Stations Using SunNet Manager” for detailed instructions on
how to manage FDDI networks using a SunNet Manager console.
Communication Between FDDI Layers
The MAC layer transfers data between peer entities in the form of frames that
are encoded as FDDI symbols by the
PHY layer. The PMD layer transmits FDDI
symbols across the network as a bit stream of light pulses (for fiber
connections) or electrical signals (for twisted-pair connections).
The communication between layers in the FDDI architectural model is
summarized in Figure 6-2.