Fnb Operations With Port Switching - Cabletron Systems TRXMIM-24A User Manual

FNB Operations With Port Switching

Management of Segmented FNB Rings
If the FNB is segmented, as shown in Figure A-1, the modules on
one segment are isolated from modules on another FNB segment;
management interfaces with one ring are isolated from other FNB
segments as well. Therefore, to receive full management support,
each FNB segment requires its own management interface; but as
management modules are added to the MMAC to manage these
rings, the number of slots available for concentrator modules is
decreased, creating greater power demands, and increasing the
overall cost per port in the MMAC.
A.4 FNB Operations With Port Switching
Each single-ring MIM (e.g., TRMIM) provides access to only one
FNB ring; all concentrator ports are permanently assigned to
connect to FNB ring 1. Each port-switching MIM (e.g., TRXMIM),
however, makes use of additional pins in its FNB connector to
create four vertically stacked, parallel FNB rings (as illustrated in
Figure A-2). With simultaneous access to four rings, port-switching
MIMs assign each of their concentrator ports on an individual basis
to connect to any of four FNB rings, providing multiple users with
access to multiple rings. Refer to Figure A-3 for a comparative
illustration of the connectivity afforded by each kind of MIM.
Port Assignment and Port Switching
Port assignments are made via the Local Management application
provided with port-assigning management modules. The
re-assignment or switching of a port from one ring to another
requires no physical reconfiguration of lobe cables: port-switching
MIM users assign concentrator ports on an individual basis to
connect to any of the four FNB rings and the connection is changed
internally by the port-switching MIM (as represented in Figure
A-4). Note, however, that without the use of a management
module, there are no means for switching port assignments: all
ports are assigned by default to FNB ring 1.
Page A-3