3-1

Chapter 3

Operation
The 9T122-24 MicroLAN Module provides connectivity between the front panel
Token Ring(s) and the FDDI rings on the backplane (FNB-1 or FNB-2).
MMAC-Plus modules connect to either the Internal Network Bus (INB) or the
Flexible Network Bus (FNB) bus. The 9T122-24 module connects to the FNB bus.
Shown in Figure 3-1 is a block diagram of the module. The front panel may be
configured as one Token Ring (factory default) or as two rings. In the two ring
configuration, the rings function as individual networks, each with twelve ports.
Bridging/Routing may occur between these two rings and/or to any other
MMAC-Plus module via the Flexible Network Bus.

Figure 3-1. 9T122-24 Block Diagram

Bridging

The 9T122-24 is configured for SRT bridging. It will pass SR (Source Routing)
frames between the rings and provides translation to transparent frames over the
FNB to Ethernet and FDDI modules. For information on configuring the bridging
function, see the addendum to the MMAC-Plus Local Management User’s Guide,
containing information specific to this model.
i960 PLUS Core FNB-1 or
FNB-2
System
Diagnostic
Controller SMB-10
SMB-1
DC/DC
Converter
Twelve
Front Panel
Connections
Twelve
Front Panel
Connections