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the UE is not authenticated by BBF access network, than the PCRF shall start the s9 session when the<br />
UE performs the attachment to the EPC, e.g. during IPsec tunnel establishment with ePDG, but this is a<br />
new procedure for the PCC. Another important open issue is related to presence of the IPsec tunnel<br />
between the UE and the EPC network which does not allow the BBF access network to manage the<br />
single IP flow bearer which is tunneled and ciphered.<br />
Figure 7.12. Reference Architecture for 3GPP-BBF Interworking – WLAN Untrusted Scenario.<br />
The current situation for a femto scenario, which is not shown in the figure, is more complex. The BBF<br />
access network is only aware of the H(e)NB which is connected to the RG, but presence of a 3GPP UE<br />
connected to a H(e)NB is completely unknown. In addition traffic between the H(e)NB and the SeGW is<br />
tunneled and ciphered. Currently, 3GPP is discussing three alternative scenarios for deriving, mapping<br />
and binding the 3GPP bearer, the IP CAN session and the aggregate information per H(e)NB and per<br />
tunnel. The different alternatives have different impact on the 3GPP part of the architecture for femto and<br />
www.4gamericas.org February 2011 Page 70
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