IBM SG24-4817-00 - Manual (Page 37)

This soft copy for use by IBM employees only.
Figure 10. Hardware Architecture of the I B M 8285 Nways A T M Workgroup Switch Base
and Expansion Unit
When the IBM 8285 expansion unit is installed, its switch chip, called a
switch-on-a-chip, becomes the primary cell switch for the 8285 system. The
CAD_up and CAD_down devices in the base unit and in any ATM modules link
directly to this switch. Another way of saying this is that the link between the
base unit
′
s CAD_up and CAD_down is disabled, and all cells (even port-to-port)
within the base unit or within an individual ATM module, are switched through
the switch-on-a-chip.
Chapter 3. Functional Overview of the IBM 8285
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