Content

| Summary

The resiliency and availability features supported by the Cisco Catalyst family of switches are well-suited to campus LAN designs that achieve high availability through a combination of device-level and network-level redundancy. The network resiliency features span Layer 2 and Layer 3 boundaries and may be deployed where needed throughout the three-tiered Access, Distribution, Core design model.

With some care in configuring the redundant network and tuning the protocol timers within the switches, interruption of network services due to network infrastructure failures can be held in the range of 0 to 10 seconds. With these short fail-over times, very high network availability can be achieved by controlling the overall network failure rate.

Upon completion of this module, the student should be able to:

- implement hardware redundancy on the Catalyst series of switches
- identify the virtual router for a given set of switch block devices
- configure HSRP on the switch block devices to ensure continual inter-VLAN routing
- maintain packet forwarding by configuring the active and standby HSRP router roles
- ensure the role of the active router by assigning a preempt status