RADIUS clusters subsystem
Reliability of RADIUS-packages processing can be increased to the level of "five nines" (availability factor of 0,99999) by arrangement of a cluster of RADIUS-servers. Cluster consists of interacting RADIUSD tarifficators, which are run on different computers.
Cluster is a combination of RADIUSD tarifficators, which are run on different servers. Tarifficators interact with each other by exchange of control and information messages. One tarifficator works in load conditions, and other tarifficators act as unloaded reserve. Unloaded tarifficator is the primary one (master), and standby tarifficators – subordinate (slave).
The main tarifficator performs function of a RADIUS-server: accepts and processes queries, returns responses, keeps account of sessions, calculates cost of services. This tarifficator is the principal link of a cluster and has current information about active sessions. It also sends messages about changes in its state to standby tarifficators. Based on these messages, standby tarifficators update their information about active sessions, current service volume, customers’ balance. Due to this fact the data composition in the primary and standby tarifficators coincide, and in case the main tarifficator fails any standby one can substitute it.
