RADIUS accounting server behavior with interactive model

RADIUS Accounting Server is used for receiving an accounting request and returning a response to a client. When the client is configured to use RADIUS Accounting, it will generate accounting requests towards accounting server. In a system where there are multiple servers configured in round-robin fashion, if some of the servers go down, it takes more time to reach the actual active server after retransmissions to the non-responsive server get exhausted. In case of accounting server not responding or dead, client keeps on archiving the requests until certain point. Once the server becomes active, client will flush all the archived requests. In this process, there are chances that some of the requests may get lost. Also it takes large amount of time to flush all the archived requests. Here we propose a new approach to make Accounting-On and Accounting-off requests to be sent by Accounting Server to Network Access Server for better communication.