Cabletron Systems 9F106-01 - Manual (Page 17)

Operation
3-2
Flexible Network Bus (FNB)
The FNB consists of two dual FDDI networks, the FNB-1 and FNB-2, providing
up to 400 Mbps of data bandwidth. These FDDI networks are 100% ANSI FDDI-
compliant, supporting SMT (version 7.3), MAC, PHY, and PMD standards. This
allows the FNB to traverse multiple MMAC-Plus hubs, or connect to any ANSI
FDDI-compliant device, through standard A/B port connections.
System Management Buses
The SMB-1 is a 1 Mbps management bus located within the MMAC-Plus. This bus
is utilized by all diagnostic controllers in the system. These include connectivity
modules, power supply modules, and the environmental module. The SMB-1
transports inter-chassis information between system components, such as power
and environmental information, as well as diagnostic messages. Periodic
loop-back tests are performed by all modules that share this bus to ensure the
validity of SMB-1.
System Diagnostic Controller
This diagnostic controller is composed of a Z-80 microprocessor and its
supporting logic. The diagnostic controller is designed to control the power-up
sequencing of modules, monitor the 9F106-01 input and output power
parameters, keep watch over the main host processor, as well as monitor the
temperature and control the SMB LANVIEW diagnostic LED. The information
gathered by the diagnostic controller is available to the network manager via
local/remote management and the LCD located on the Environmental Module.
The 9F106-01 have been designed so that in the event of a diagnostic controller
fault, the modules will continue to function.
DC/DC Converter
The DC/DC converter converts the 48 VDC on the system power bus to the
necessary operating voltages for its host network services module. The diagnostic
controller controls the operation of the DC/DC converter.