Cabletron Systems TRMM-2, Руководство пользователя

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INTRODUCTION TO MULTIPLE-RING MMAC FUNCTIONALITY
A-2
A.3 COMPARING PORT SWITCHING AND SINGLE RING
MIMS
The FNB serves as a single Token Ring (FNB Ring 1) for topologies
comprised of MIMs that do not support port switching (such as a
TRMIM-24A and TRRMIM-2AT). Each MIM in the MMAC may attach
to adjacent MIMs and operate together; or can “wrap” (bypass) their
connection to the MIM on either side, segmenting the FNB into multiple,
isolated Token Rings, as illustrated in
Figure A-1 .
Figure A-1. FNB Segmentation Produces Two Isolated FNB Rings
Each port switching MIM (such as the TRXMIM) 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 FNB
rings. Port switching MIMs switch each of their ports to one of these FNB
rings, providing all users with access to multiple rings. Each FNB ring is
an isolated Token Ring and these rings do not communicate with each
other through the FNB. See
Figure A-3 for a comparative illustration of
the FNB connectivity of port switching and single ring MIMs.
TRMIM-24A TRMIM-24A TRMIM-24A TRMM TRMIM TRMIM TRMIM-24A TRMMIM
FNB ring wrapped at TRMMIM's right FNB interface.
FNB ring
segment A FNB ring
segment B