Operation
3-2
Flexible Network Bus (FNB)
The FNB consists of two dual FDDI networks, 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 systems, or connect to any
ANSI FDDI-compliant device, through standard A/B port connections.
System Management Buses
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 1 Mbps 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 that 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 10 Mpbs management bus located within the MMAC-Plus which
is also 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 that 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.
