■ Availability—Availability is always a major concern to network managers. A network’s
ability to overcome outages and adapt to changes is paramount. Three availability issues
are incorporated into the Cisco AVVID design model:
— Equipment and link redundancy—This includes not only redundant
components and high-availability configurations but also redundancy
within the equipment, such as dual power supplies and other features
designed into the modular products.
— Protocol resiliency—The focus here is to use the most resilient protocol.
Multiple redundant protocols do not necessarily provide the best solution.
— Network capacity design—A network design should allow for significant
expansion and support the capacity needs and redundancy to reduce the
impact of a redundant link failure.