TLP uses the concept of baselines, which are a set of patches and patch revisions that are frozen at a given point in time. This set is tested as a unity and doesn't change after it is released. Baselines enable you to bring all of your systems to the same patch level. The baselines are tested together, thereby reducing the risk of patch incompatibilities. Having all the systems in a large data center at the same patch level makes administration and error detection much easier.
Baselines usually change once per quarter. First, an appropriate baseline is selected. For example, an EIS-CD dated, January 2005 would contain all of the patches that were burned in January of 2005. The baseline is installed once per quarter. When a new baseline is installed, TLP automatically updates the various reports.