Describing High Availability in Multilayer Switching
What is redundancy in a switched network?

Providing hardware redundancy in a switched network can be accomplished by implementing redundant modules within devices or by deploying redundant devices.

To achieve network availability as close to 100 percent of the time as possible, these network components are required:

  • Reliable, fault-tolerant network devices – Hardware and software reliability to automatically identify and overcome failures.
  • Device and link redundancy – Entire devices may be redundant or modules within devices can be redundant. Links may also be redundant.
  • Resilient network technologies – Intelligence that ensures fast recovery around any device or link failure.
  • Optimized network design – Well-defined network topologies and configurations designed to ensure there is no single point of failure.
  • Best practices – Documented procedures for deploying and maintaining a robust e-commerce network infrastructure.

Network fault tolerance indicates the ability of a device or network to recover from the failure of a component or device. Achieving high availability relies on eliminating any single point of failure and on distributing intelligence throughout the architecture. You can increase availability by adding redundant components, including redundant network devices and connections to redundant Internet services. With the proper design, no single point of failure will have an impact on the availability of the overall system.