3-3
INB NIB
Each module that attaches to the Internal Network Bus (INB ) has an INB
Network Interface Block (NIB). The INB NIB converts canonical frames to fixed
length data blocks for transmission onto the INB. For data blocks received from
the INB, the INB NIB reassembles the data blocks received from the INB back into
canonical frames for transmission to the Fast Packet Switch (FPS) then from the
FPS to the front panel ports.
There are two management channels within the MMAC-Plus 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 MMAC-Plus. 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 MMAC-Plus. This
bus is used for inter-chassis communication of modules as well as serving as an
out-of-band management channel into the MMAC-Plus. 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 MMAC-Plus 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. If a fault is detected on the SMB-10,
the SMB-1 is used by the modules as an alternate communication channel.
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 9E312-12 input and output power
parameters, keep watch over the main host processor, monitor the temperature,