High Availability Network Fundamentals

Parallel Topology

Unlike in serial topology, the fail-over mechanism is crucial to the operation of a parallel topology. Whether the fail-over mechanism is a bridging protocol, routing protocol, or some other method, you need to consider it carefully while performing availability calculations. This early in the book, we are going to assume that fail-over mechanisms work properly and instantly. Later, we are going to assume that the different fail-over mechanisms take a certain amount of time, and then we are going to add that time to our calculations.

In order to illustrate the parallel topology and its associated availability, we will use Figure 3-3 and Figure 3-4. Figure 3-3 shows a very simple parallel topology network. Figure 3-4 shows the ...