The proper design of a network infrastructure should allow for a number of key traits that are very desirable in an overall network design. First, the infrastructure needs to provide redundancy and resiliency without a single point of failure. Second, the infrastructure must be scalable in both geographic reach as well as bandwidth and throughput capacity.
Ideally, as one facet of the network is improved, such as resiliency; it should also improve on bandwidth and throughput capacity as well. Certain technologies work on the premise of an active/standby method. In this manner, there is one primary active link – all other links are in a standby state that will only become active upon the primary links failure. Examples of this kind of approach are 802.1d spanning tree and its descendants rapid and multiple spanning trees in the layer 2 domain and non-equal cost distance vector routing technologies such as RIP.
While these technologies do provide resiliency and redundancy they do so at the assumption that half of the network infrastructure is unusable and that a state of failure needs to occur in order to leverage those resources. As a result, it becomes highly desirable to implement active/active resiliency Continue reading