<P>The Catalyst 8500 CSR family of Campus Switch Routers provides the next-generation switching paradigm for both switching performance and critical network services. Including support for all IP and IPX routing standards, the Catalyst 8500 CSR family of campus backbone switches offers a complete suite of sophisticated features. The Catalyst 8500 CSR family contains several key components of the new enterprise campus network architecture, providing for high-speed performance, resiliency, quality of service (QoS), and security within the network backbone. With new ATM and Packet-over-SONET uplinks, the Catalyst 8540 CSR delivers metropolitan area network (MAN)/wide area network (WAN) solutions with scalable performance, lower cost of ownership, and the features needed in New World Networks. </P> <P> This product is a CSR Switch Processor for the Catalyst 8540. The Catalyst 8540 CSR chassis supports fault tolerance by allowing a secondary switch processor to take over if either one of the primary switch processors fail. You must have two switch processors for proper operation. When three switch processors are installed, two are active at any one time, while the third runs in standby mode. By default, slots 5 and 7 are active and slot 6 is the standby. The module can be configured differently if needed. </P>