Question: When an I/S-CSCF applies traffic reduction as per IETF RFC 7683, which of the following types of Diameter requests are typically the last to be throttled, based on regulatory and operator policies?
Option 1: All Diameter requests related to new user registrations
Option 2: Diameter requests for non-priority SIP message routing
Option 3: Diameter requests related to priority traffic (e.g., MPS) and emergency services, identified by specific headers (e.g., Resource-Priority)
Option 4: Requests for Quality of Service (QoS) adjustments in video calls
Explanation: This is because priority traffic, such as Multimedia Priority Service (MPS), and emergency services are critical and typically given the highest priority. The presence of specific headers like the Resource-Priority header field in SIP messages indicates these high-priority requests. As per the described behavior, these would be the last to undergo throttling when an I/S-CSCF applies traffic reduction measures, adhering to regional/national regulatory and operator policies to ensure uninterrupted service for emergency and priority communications.