Dialogic INTEGRATED MEDIA GATEWAYS 1010 - Manual (Page 12)

RADIUS
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RADIUS Server Redundancy
The IMG 1010 supports an Active Standby redundancy scheme. Redundancy logic
is independent for Authentication and Accounting Servers.
When configuring RADIUS servers you may create them with an initial priority
preference. The IMG will begin using the preferred Server(s) and switchover to an
alternate server after detecting a communication failure to the currently active
server.
Once the switchover occurs all future Radius messages will flow to the newly active
server until a failure occurs on this server. If an error is detected in trying to send
a Radius message to this newly active server, the IMG will attempt to switch again
back to the previously active server. This behaviour is repeated, until a working
server is detected. If the IMG fails to connect to a RADIUS Server an alarm will be
sent. You can monitor alarms using EventView.
Typically when a RADIUS message needs to be sent to a server, it is assembled
and passed to the OS for transport to the currently active server. These servers are
configured to send the message, wait 2 seconds and then retry sending the
message an additional 3 times. Therefor a RADIUS message will be sent a total of
4 times, with 2 second intervals, before attempting a switchover to the next
server, if one is configured. The switchover behaviour is coupled to the message
type. Therefore an Accounting Server switchover is independent of an
Authentication Server switchover.
Under typical call load it will take a while for the switchover to complete since the
IMG may have many RADIUS messages queued up to the failed server. Each of
these messages must fail and be retried on the newly active server following
notification of the send failure.
NOTE: A negative response does not constitute a server failure.
Supported Packet Types
• Access-Request
Sent to a RADIUS server - conveys information used to determine whether
a user is allowed access to a specific NAS, and any special services
requested for that user.
• Access-Accept
Sent by the RADIUS server - provides specific configuration information
necessary to begin delivery of service to the user.
• Access-Reject
Sent by the RADIUS Server if any value of the received Attributes is not
acceptable
• Accounting-start
• Accounting-stop
RADIUS Server Debug Mode
You can configure your RADIUS Client in Debug Mode so that calls will be
completed whether the RADIUS server is active or not. The IMG will not require
authentication for the RADIUS server to complete a call and no billing information
will be logged.
You enable RADIUS Debug Mode using the
RADIUS Client screen.
RADIUS Server Failure Alarm