Question: Which protocols are utilized by the CSC-15 reference point for transporting and routing non-subscription/notification related signaling between the Location Management Server and the MC Service Server?
Option 1: SIP-1 and SIP-2 exclusively
Option 2: HTTP-1 and HTTP-2 exclusively
Option 3: A combination of SIP-1, SIP-2, HTTP-1, and HTTP-2 depending on the signaling type
Option 4: Only TCP/IP for all types of signaling
Explanation: The CSC-15 reference point employs a differentiated approach based on signaling type. For non-subscription/notification related signaling, it relies on HTTP-1 and HTTP-2, while also utilizing SIP-1 and SIP-2 for other types, thus using a combination based on signaling type.