17
Connecting the Network Cables
Connecting the Network Cables
The FDDI Module uses a dual-port FDDI interface, with two FSD (fixed shroud
duplex) connectors labeled MIC A and MIC B (media interface connector).
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Either MIC A or MIC B is used to attach the switch to a single attach station
(SAS)
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Both MIC A and MIC B are used in one of the following ways:
•
To attach the switch as a dual attach station (DAS)
•
To attach the switch to two single attach stations
•
To set up the switch as a dual-homed device
Avoiding Ring Wrapping.
On a DAS, you can use an (optional) optical
bypass switch (also known as an “FDDI dual-switch module”). A bypass
switch prevents the FDDI ring from “wrapping” if the switch connected as a
DAS loses power or if the FDDI port becomes disabled. Another technique
that eliminates the need for a bypass switch is dual homing, which isolates a
cable or concentrator failure so that it will not break the switch’s connection
to the FDDI ring. An example of ring wrapping is illustrated on page 24.
N o t e
If the FDDI cable is disconnected or faulty, the bypass will not activate and
ring wrapping will not be prevented.
Ring wrapping is discussed further in the table on page 22.
