Iu Connection Procedures; Iu Connection Establishment Procedure - Cisco ASR 5000 Series 3G Home NodeB Administration Manual

▀ How HNB-GW Works
2. The UE then transmits a RRC Initial Direct Transfer message carrying the initial NAS message (e.g. Location
Updating Request message) with identity (IMSI or TMSI).
3. The HNB checks UE capabilities provided in step 1, if these indicate that CSG is not supported and if the
identity of the UE (provided during RRC Connection Establishment) is unknown at the HNB being accessed,
i.e. no Context id exists for the UE, the HNB initiates UE registration towards HNB-GW (step 6-8).
4. Before starting the UE Registration procedure, HNB optionally triggers the Identification procedure asking for
the UE IMSI, if such identity is not provided during the RRC Connection Establishment. If the HNB has a
context id for the UE, the UE registration procedure is not performed nor the Identification procedure.
5. The HNB may optionally perform access control based on IMSI and provided access control list.
6. The HNB attempts to register the UE on the HNB-GW by transmitting the UE-REGISTER-REQUEST. The
message contains at a minimum:
 UE Identity: IMSI of the (U)SIM associated with the UE and the indication about UE capabilities
7. The HNB-GW checks UE capabilities and if these indicate that CSG is not supported the HNB-GW shall
perform access control for the particular UE attempting to utilize the specific HNB.
8. If the HNB-GW accepts the UE registration attempt it shall allocate a context-id for the UE and respond with a
UE-REGISTER-ACCEPT message, including the context-id, to the HNB. If the HNB-GW chooses to not
accept the incoming UE registration request then the HNB-GW shall respond with a UE-REGISTRATION-
REJECT message.
9. The HNB then sends a RUA (RANAP User Adaptation) CONNECT message containing the RANAP Initial UE
message to HNB-GW.
10. The reception of the RUA CONNECT message at the HNB-GW triggers the setup of SCCP connection by the
HNB-GW towards the CN. HNB-GW forwards the Initial UE Message to CN.
11. The CN response with a SCCP Connection Confirm message to HNB-GW.
12. The UE then continue with the NAS procedure (e.g. Location Updating procedure) towards the CN, via HNB
and the HNB-GW.

Iu Connection Procedures

This section describes call flow for Iu connection procedures on HNB-GW.
Following procedure call flows are described for Iu connection procedures between HNB, HNB-GW, and SGSN/MSC
in core network:


Iu Connection Establishment Procedure


Network Initiated Iu Connection Release Procedure
Iu Connection Establishment Procedure
This procedure is applicable for establishment of IuH and IuPS/IuCS connection between HNB to HNB-GW and HNB-
GW to SGSN/MSC in core network.
The following figure and the text that follows describe the message flow for an Iu connection establishment procedure.
▄ Cisco ASR 5000 Series 3G Home NodeB Gateway Administration Guide
44
provided in step 1.
Important:
The UE IMSI provided in the UE-REGISTER message is unauthenticated.
HNB Gateway in Wireless Network
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