Cabletron Systems MMAC-Plus 9T125-24, User Manual

Operation

3-4

System Management Buses

There are two management channels within the SmartSwitch 9000 system: the 
SMB-1 and the SMB-10. These buses provide out-of-band management and inter-
module management communication.

SMB-1 Bus

The SMB-1 is a 1Mbs management bus located within the SmartSwitch 9000. This 
bus is utilized by all diagnostic controllers in the system including 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 which share this bus to ensure the 
validity of SMB-1. In the event a failure is detected on SMB-1, the SMB-10 may be 
used as an alternate communication channel.

SMB-10 Bus

The SMB-10 is a 10Mbs management bus located within the SmartSwitch 9000 
which is also used for inter-chassis communication of modules as well as serving 
as an out-of-band management channel into the SmartSwitch 9000. The SMB-10 is 
externalized from the chassis via an optional Ethernet Port Interface Module 
(EPIM) located on the front of the Environmental Module. Through an EPIM 
connection, full SNMP management of the SmartSwitch 9000 is available out-of-
band from user data. Modules which share the SMB-10 bus periodically send out 
loop-back packets to ensure the validity of SMB-10. In the event a fault is detected 
on the SMB-10, the SMB-1 can be used as an alternate communication channel by 
the modules.

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 9T125-24 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. Although the 
diagnostic controller and the main host processor can operate independent of 
each other if needed, they exchange information about each others status and 
overall module condition. The information gathered by the diagnostic controller 
is available to the network manager via local/remote management and the LCD 
located on the environment module. The 9T125-24 have been designed so that in 
the event of a diagnostic controller fault, the modules will continue to function.