Distinct VoLTE Processes

For VoLTE calls, the process for generating CDRs is the largely the same as for other calls. As described, there are additional data points included for these call types.

In addition, the list below presents additional processes reserved for VoLTE data management with which you should be familiar:

• When there is an SRVCC event, the SBC creates a separate set of CDRs for the handover session. The SBC correlates the original and handover session using the "Generic-ID" field, which points to the Call-ID of the initial session. In addition, the SBC populates the Generic-ID field within the Initial Session CDRs (STOP), with the HO session Call-ID.
• The SBC copies the Call id of the second INVITE (Handover INVITE) into the Generic Id into the CDR for the first INVITE (initial call) for both MO and MT call
  • For mobile originating call—When the SBC receives the 200 Ok for the BYE from UE, it inserts the Call id of second INVITE, which is generated from the MSC-S as Generic Id, into the CDR of First MO Invite (Before the handover call).
  • For mobile terminating call—When the SBC receives the 200 Ok for the BYE from UE, it inserts the Call id of the second INVITE, which is generated from the MSC-S as Generic Id, into the CDR of the first MT INVITE (before the handover call).
  • If there is a negative case, such as a BYE timeout, the SBC writes the Call id of second INVITE, which is generated from the MSC-S as the Generic Id, into the CDR of the first INVITE (before the handover call) when that corresponding call gets terminated.

Note:

The SBC performs these same processes for both RADIUS accounting when generating CDRs and Diameter accounting when generating ACRs.