The vendor-specific attribute (VSA) [228], Alc-Triggered-Acct-Interim, can be used in a Change of Authorization message to trigger an interim accounting message. This feature requires the accounting mode to have interim updates enabled. You can enable interim updates using, the config>subscr-mgmt>radius-acct-plcy>host-accounting interim-update command. The VSA can hold a string of up to 247 characters. The accounting interim echoes this string in the interim message under the same Alc-Triggered-Acct-Interim VSA along with Alc-Acct-Triggered-Reason = CoA-triggered. If the VSA is left blank, it still triggers the accounting interim message with Alc-Acct-Triggered-Reason = CoA-triggered (18), but without the Alc-Triggered-Acct-Interim attribute. If the subscriber session has multiple accounting policies or modes enabled, multiple interim messages are generated. Some CoAs, such as SLA profile or sub-profile changes, triggers accounting update messages to be generated automatically. These CoAs can automatically generate one or more accounting interim messages. If these CoAs also include the Alc-Triggered-Acct-Interim VSA, no additional interim accounting messages are generated. The last automatically-generated accounting interim message contain these reasons:
the reason for the triggered interim message (such as an SLA start)
the CoA-triggered (18) Alc-Triggered-Acct-Interim attribute that is echoed on the triggered accounting interim message if the VSA is not empty