Question: In a UMTS network, when performing relocation or handover, what triggers the 3G_MSC-B to generate Alternative RAB Parameters Value IE sent to an RNS?
Option 1: Receipt of Prepare Handover Request MAP message
Option 2: Completion of Forward Access Signalling Request MAP message for intra-MSC handovers
Option 3: Automatic timer expiration in the 3G_MSC-B for pending handovers
Option 4: Direct request from the User Equipment (UE) for channel type alteration
Explanation: The generation of Alternative RAB Parameters Value IE by the 3G_MSC-B, for relocation or handover to UMTS, is triggered by the receipt of specific MAP messages. Among the provided options, only the Prepare Handover Request MAP message directly relates to the initiation of this process as stated in the context of transferring Alternative Channel Type information to 3G_MSC-B, thereby influencing the generation of Alternative RAB Parameters for handovers.