6.2 Fine-Tuning the Request Queue

As described in 3.4.1 Checking for Duplicate Requests, each request is added to the request queue when radiusd starts processing it and is removed from there a certain amount of time after its processing was finished. The configuration parameter request-cleanup-delay defines how long each already processed request is kept in the queue. Its value must be synchronized with the NAS settings.

Each NAS allows to configure two parameters:

Ntimeout

The amount of time in seconds during which the NAS is waiting for a response from radius server.

Nretries

The number of times the NAS tries to re-send the request if it received no response from the radius server.

Of course, these parameters are named differently for different makes of NASes. Refer to your NAS documentation to find out where these values are configured.

In general, these parameters must satisfy the following relation:

request-cleanup-delay = Nretries * Ntimeout + const

where const is an empirical constant that depends on the average time of processing a single request. Usually its value lies between 0 and 10 seconds.

For example, if the configuration of your NAS sets

Nretries = 3 Ntimeout = 10

then your raddb/config should contain:

auth { request-cleanup-delay 40; }; acct { request-cleanup-delay 40; };

Notice the duplication of request-cleanup-delay: radiusd uses distinct values for authentication and accounting requests, however most existing NASes do not make such distinction.