Cisco ASR 5000 Administration Manual page 87

Gx Interface Support
Figure 13.
Table 7. HA/PDSN Rel. 8 Gx IMS Authorization Call flow Description
Step Description
1 UE (IMS subscriber) requests for MIP Registration Request.
2 SessMgr allocates an IP address to the UE.
3 SessMgr requests IMS Authorization, if IMSA is enabled for the subscriber.
IMSA service can either be configured in the subscriber template, or can be received from the AAA.
4 IMSA allocates resources for the IP-CAN session, and selects the PCRF to contact based on the user's selection key (for
example, round-robin).
5 IMSA requests the DPCA module to issue an auth request to the PCRF.
OL-27210-02
HA/PDSN Rel. 8 Gx IMS Authorization Call Flow
Cisco ASR 5000 IP Services Gateway Administration Guide ▄
Rel. 8 Gx Interface ▀
87