Cisco ASR 5000 series Product Overview page 192

▀ ASN Call Procedure Flows
The serving BS generates these messages. The serving BS generates a different HO Request transaction for
each target BS. In other words, the gateway does not generate multiple HO Request messages after receiving a
single HO Request message with multiple target BSs. Generally, the HO transaction is initiated by the serving
BS which also chooses the selected target BS to which the handover will take place.
Security Context Retrieval: The ASN Gateway supports the retrieval of the security context using Context
Request and Context Report messages. This retrieval is also stateless. The context retrieval operation can be
performed at any time during the lifetime of a call.
Data Path Registration: After Pre-Registration, the target BS performs Data Path Registration. Data Path
Registration is performed using a 3-way handshake. If Pre-Registration has occurred, the Data Path
Registration messages do not contain any service flow information.
Preparation Phase
The following figure and table provides a high-level view of the steps involved during the preparation phase of a
controlled inter-ASN Gateway handover of an SS/MS from an anchored gateway to a non-anchored gateway.
▄ Cisco ASR 5000 Series Product Overview
If Pre-Registration has not occurred, the Data Path Registration messages carry the service flow
information.
Data Path Pre-Registration and Data Path Registration is initiated by the BS.
ASN Gateway Overview
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