Introduction to Availability and Redundancy
There are two methods of providing basic redundancy services: chassis redundancy and component redundancy. Chassis redundancy has another networking device, with the same functionality, that provides redundant services in case the primary device fails. Component redundancy provides for redundant components inside the same chassis. Six key components are used to reach a high level of availability (as close to 100% as possible):
Network device reliability— Redundant hardware components and intelligent software should be able to deal with a failed component.
Device redundancy— Redundant devices are used in case one device fails.
Link redundancy— Backup network connections are used in case a primary network ...