Date Added: Oct 2009
The main objective of the Institute Tier Standard: Topology is to describe the site level infrastructure that is required to sustain data center operations. This topology can also be used compare the functionality, capacity, and expected availability (or performance) of a particular site. Tier standard topology is especially used to rate the weakest subsystem of an entire site that can have an impact on the functioning of the site. A site's Tier rating is not the average of the ratings for the critical site infrastructure subsystems but it is the lowest of the individual subsystem ratings. Therefore, data center site infrastructure Tier Standard: Topology mainly focuses on the performance of an individual site. This paper largely pays attention to the various Tier standards set by the data center site infrastructure to describe criterias and to differentiate between four classifications of site infrastructure topology based on increasing levels of redundant capacity components and distribution paths. The standard also focuses on the definitions of the four Tiers and the performance confirmation tests for determining compliance to definitions. The paper concludes with The Commentary, which provides practical examples of site infrastructure system designs and configurations that fulfill the Tier definitions as a means to clarify Tier classification criteria.