Cabletron Systems manual Fddi Devices, BRIM-F6 User’s Guide A-9

FDDI Devices

Port A Port B Port A Port B

	1						2
Port M		Port M			Port M			Port M
Backup						Primary
Connection			Port A	Port B		Connection

3

Figure A-6. Dual Homing Topology

Concentrator 3 in Figure A-6 has redundant connections to the main ring through either concentrator 1 or 2. The FDDI connection rules only permit one active connection, Port B. If a cable failure severs concentrator 3’s connection to concentrator 2, CFM activates Port A.

A.6 FDDI Devices

FDDI recognizes four station configurations (SAS, DAS, DAC, and SAC). These configurations differ by the mix of FDDI entities within the station (see Figure A-7).

All stations must have:

•one SMT

•at least one MAC

•one PMD

•one PHY.

BRIM-F6 User’s Guide Page A-9