Using the BayStack 450 10/100/1000 Series Switch1-12 309978-D Rev 01Redundant Power Supply Unit (RPSU) ConnectorThe RPSU connector allows you to connect a backup power supply unit to theswitch. Nortel Networks provides an (optional) high-power redundant powersupply unit (HRPSU) for this purpose. The HRPSU is a hot-swappable powersupply unit that provides uninterrupted operation to up to four BayStack 450switches in the event that any of the switch power supplies fail.Nortel Networks provides the HRPSU power rack (Order No. AA0002001) withfour slots for power supply modules (Order No. AA0005003). Each HRPSU cansupport up to four BayStack 450 switches. Installation instructions are providedwith the HRPSU (refer to Installing and Maintaining the HRPSU (Part number114312-D).Contact your Nortel Networks sales representative for more information about theHRPSU.Cascade Module SlotThe Cascade Module slot allows you to attach an optional BayStack 400-ST1Cascade Module to the switch (see “Stack Operation” on page 1-39).You can connect up to eight BayStack 450 switches to form a redundant stackconfiguration. BayStack 450 switches use a fail-safe cascade stacking architecturewhich, in the unlikely event of a switch failure, maintains the integrity of theremaining stack: all signals are looped back at the point of failure. Because eachunit in the stack has a full copy of the stack configuration, operation of the stackcontinues without affecting application connectivity.Any mix of up to eight BayStack 450 switches, BayStack 410-24T switches, andthe Business Policy Switch 2000 can be stacked to provide a total of 224 portswhen all MDA slots are configured with the maximum port availability (certainrestrictions apply, see “Stack Operation on page 1-39).Installation instructions are provided with each BayStack 400-ST1 CascadeModule (see Installing the BayStack 400-ST1 Cascade Module).See your Nortel Networks sales representative for ordering information.
