Question: For Mission Critical (MC) services, what is a key requirement for protocols used on reference points exposed for interoperability with other SIP core or IMS entities in different systems?
Option 1: They must be customized for each specific MC service type.
Option 2: They should align with IETF (Internet Engineering Task Force) standards only.
Option 3: They can vary depending on the vendor implementation.
Option 4: They shall be compatible with protocols defined in standardized network architecture specifications for corresponding reference points.
Explanation: To ensure seamless interoperability and maintain standardized communication, MC services must adhere to established protocols. Compatibility with standardized network architecture for the respective reference points is crucial for unified functionality across different systems and entities, highlighting the importance of standardization in telecom networks.