Question: In an IMS network, when multiple contact addresses are registered for a Public User Identity, how does the S-CSCF determine whether to use parallel or sequential forking if the UE has not indicated any preference for the matching contact addresses upon registration?
Option 1: The S-CSCF always defaults to parallel forking to ensure simultaneous attempts to reach the user.
Option 2: The decision is based solely on the capability information of the UE as described in IETF RFC 3840.
Option 3: It depends on the type of SIP request (e.g., INVITE, MESSAGE, etc.) being forked.
Option 4: It is up to the configuration of the S-CSCF for the matching contact addresses with equal preference value.
Explanation: According to the IMS specifications, if the UE has not indicated any preference for the matching contact addresses upon registration, or if the preferences for the matching contact addresses have equal value, the S-CSCF's behavior (whether to perform parallel or sequential forking) is determined by its own configuration settings. This highlights the importance of network configuration in managing call handling when user preferences are not explicitly stated.