IBM SG24-4817-00 manual This soft copy for use by IBM employees only

This soft copy for use by IBM employees only.

Figure 10. Hardware Architecture of the IBM 8285 Nways ATM 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 21