Cisco ASR 5000 series Product Overview page 443

Packet Data Interworking Function Overview
Figure 121. Simple IP Fallback Message Sequence
Table 65.
Step Description
1 With the IPSec Child SA (Security Association) and TIA already in place, the PDIF sends advertisements to the MS.
2 The MS sends a Registration Request (RRQ) message to the PDIF. The PDIF sends an authentication request to the AAA
server over the RADIUS interface.
3 The AAA server authenticates successfully and sends the IP address of the HA.
4 The PDIF forwards the RRQ message to the HA.
5 The HA denies the request. The PDIF forwards the denial code to the MS.
6 The session setup timer expires and the PDIF goes into fallback mode. The PDIF sends a RADIUS Accounting Start
message.
7 The AAA server sends a RADIUS Accounting Response message.
8 The PDIF updates the HSS with the TIA address of the subscriber.
9 The HSS sends an acknowledgement to the PDIF.
OL-22938-02
Simple IP Fallback Message Sequence
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