This feature enables the RADIUS server to indicate the appropriate state regardless of the timing of keep-alive transmissions.

When the AAA RADIUS servers are configured, the Authentication server state is set to “INIT”. In "INIT" state, the server is initialized with the context-specific configuration and prepared to send the Access request. Once the Access request is sent, the server state is moved to “Active Pending”. After receiving positive response on the SRP Active chassis, the server state is moved to “ACTIVE”. Meanwhile, after configuring the Accounting server, the state is set as "Active" on both chassis.

To implement this feature, the server states are updated at the time of initial configuration and during Interchassis Session Recovery (ICSR) switchover on SRP Standby Chassis. Initially on standby chassis, servers are kept in “Active Pending” state, as the RADIUS servers are being initialized with the context-specific configuration. After the configuration completion, Access-request is sent for the Authentication server, and accounting request is sent for the accounting server as a significance of keep-alive messages. But, no response is received for these keep-alive messages because of the standby chassis. So, after the keep-alive timeout, the server state is automatically changed to “Down”.

In ICSR switchover scenario, when SRP messages are received on the Active chassis, which is going to be a new Standby chassis, the state of the servers are changed to “Active Pending”. As per the state flow, keep-alive messages are sent towards the RADIUS servers, and like the previous scenario, no response is received from the RADIUS servers. So, after the keep-alive timeouts, the server state is automatically changed to “Down”.

There is no specific configuration required for this feature. When you configure any RADIUS accounting server, it displays the appropriate state according to the chassis state.

The following is a sample configuration for configuring the AAA RADIUS servers:

config
	context ISP1
		apn intershat
		mediation-device context-name ISP1
		exit
	exit
exit
config
	context ISP1
		aaa group default
			radius attribute nas-ip-address address 209.165.200.225
			radius accounting interim interval 60
			radius mediation-device accounting server 209.165.200.226 key secret port 1813
			radius keepalive timeout 4
			radius keepalive retries 3
			radius keepalive interval 30
			radius accounting algorithm round-robin
			radius accounting detect-dead-server keepalive
			radius accounting keepalive timeout 4
			radius accounting keepalive username 001001110990001@pgw.keepalive
			radius accounting keepalive calling-station-id 999255255255005
			radius accounting keepalive framed-ip-address 255.255.255.224
			radius max-retries 0
			radius accounting max-retries 0
			radius max-transmissions 2
			radius accounting max-transmissions 2
			radius timeout 1
			radius accounting timeout 15
			no radius accounting archive
			exit
		exit
	exit
exit

This section describes the CLI commands available to monitor and/or troubleshoot the feature.