The Catalyst 5500 is a 13-slot chassis with two dedicated slots - slots 1 and 13. Slot 1 is dedicated for the Supervisor Engine that monitors all system components and is responsible for all frame-switching and forwarding functions in the switch. Supervisor Engine II or Supervisor III is required for operation of the Catalyst 5500. A Supervisor II is a 1.2Gbps switch fabric. A Supervisor III is a 3.6Gbps crossbar switching fabric. Slot 13 is the second dedicated slot and is reserved for the LS1010 ATM Switch Processor (ASP) module or Catalyst 8510 Switch Route Processor (SRP). The ASP or SRP modules are 10 Gbps switching fabrics and are required if interface modules from the LightStream 1010 or Catalyst 8510 are to be used in the Catalyst 5500.The Catalyst 5500 architecture is based on a combination of two high-capacity switching fabrics integrated into a single platform. This architecture ensures optimal performance whether the Catalyst 5500 is used as a high-density cell or a frame switch. All Catalyst 5000 Family interface modules can be used in slots 2 to 12, whereas LightStream 1010 or Catalyst 8510 modules can be used in slots 9 to 12. Slot 2 is a dual-purpose slot that can be used for either a redundant Supervisor Engine or any Catalyst 5000 family interface module. With its support for hot-swappable modules, power supplies, and fans, the Catalyst 5500 chassis delivers high availability for production networks. Dual redundant switching engines, power supplies, and a passive backplane design ensure full system redundancy for mission-critical environments. The Catalyst 5500 chassis fits into a standard 19-inch rack, and all system components are accessible from the same side of the chassis. Only one power supply is required to run a fully configured system.