What is the Purpose of Using Validity-Time AVP in CCA?

Question

Does the GGSN have an internal validity time configuration to terminate a gprs session?

Answer 1

In short, when diameter client sends Credit-Control-Request command message to diameter server. Diameter server may include Validity-Time AVP with the Credit-Control-Answer message.

The intention to include such AVP is to set a validity period for a granted resources. If user is not able to granted resource within the validity period. Client again sends Credit-Control-Request message to server with the Update request rather than initial request .

Answer 2

The validity time will indicate the time the granted quota is considered valid. There is no default
value for the Validity-Time. If the AVP is missing then the associated quota is valid indefinitely.

This is to save resources.
Imagine situation you are browsing i.e. facebook before falling asleep. You were granted let say 10mb.
Now the OCS has to remember it has session opened with you, it granted you quota and waits for consumption report.
Also PGW/GGSN who is counting this quota is assigning the resources to keep all this information in memory.

It's easier to assign the time during the quota is valid and then report it back to OCS and "forget" all the information about your session.

Comments

Hello Bart, could you please give me some technical support for this answer? I'm not doubting, it's just that I need it.
thanks in advance!

Answer 3

The main purpose of using Validity-time is to ensure control by OCS on the GGSN to ensure that the allocated quota for consumption is put to use effectively within the stipulated time. The allocated quota (volume) to be consumed has the validity within that time frame specified by the QVT.
If the quota is not consumed fully, still the GGSN will communicate to the OCS (only with the validity time timer) on the Used value (USU) and the new request (RSU) based on the trend that is followed by the user in that session.
This ensures the optimal use of resources by the OCS on its end., - for capturing the user related data.