Question: What is the correct format for constructing the EPC nodes DNS subdomain (DNS zone) in accordance with 3GPP specifications?
Option 1: node.epc.mnc<MNC>.mcc<MCC>.3gppnetwork.org
Option 2: epc.node.mnc<MNC>.mcc<MCC>.3gppnetwork.org
Option 3: mnc<MNC>.mcc<MCC>.node.epc.3gppnetwork.org
Option 4: mcc<MCC>.mnc<MNC>.epc.node.3gppnetwork.org
Explanation: The correct format for constructing the EPC nodes DNS subdomain (DNS zone) is by adding the label "node" to the beginning of the Home Network Realm/Domain, resulting in node.epc.mnc<MNC>.mcc<MCC>.3gppnetwork.org. This ensures that the operator has control over the DNS subdomain and can provision any DNS records without concern about future 3GPP standards encroaching on the DNS names within this zone.