Oracle Communications Session Border Controller — Question 39

How does the Session Border Controller ensure that a pinhole is kept open for persistent communication to a SIP endpoint behind a NAT device?

Answer options

• A. by changing the expires= parameter to a defined value in 200 OK responses to REGISTERs
• B. by changing the expires= parameter to a defined value in 200 OK responses to INVITEs
• C. by issuing PINGs to the endpoint's NAT address
• D. by sending Address Resolution Protocol (ARP) requests at a defined frequency
• E. by sending messages at a defined frequency

Correct answer: D

Explanation

The correct answer is D, as sending ARP requests at regular intervals helps keep the NAT pinhole open for the SIP endpoint. The other options do not directly relate to maintaining NAT pinholes; changing parameters in REGISTERs or INVITEs and sending PINGs do not ensure persistent communication in the same way ARP requests do.