Refer to the exhibit. Which statement about when user A calls user using SIP is true?
A. SIP TCP/TLS ports must be opened from internal to DMZ and vice versa.
B. Cisco VCS Control and Cisco VCS Expressway support static NAT.
C. Deploying a Cisco VCS Control inside a NAT mandates the use of the Advanced Networking option key.
D. RT and RTCP ports must be opened at the firewall from internal to DMZ and vice versa.
I could only find expe with static nat config, not expc
I assume they are calling c
https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/expressway/config_guide/X8-5/Cisco-Expressway-Basic-Configuration-Deployment-Guide-X8-5-2.pdf
The Advanced Networking option is available only on the Expressway-E.
I think the answer A-C-D are correct;
https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/expressway/config_guide/X8-5/Cisco-Expressway-Basic-Configuration-Deployment-Guide-X8-5-2.pdf
is the point of this question that the proxy nature of calls ONLY flow from Exp-E toward Exp-C but that the Control will NOT proxy a call out to the external DMZ user via the Exp-E