Exam 300-820 topic 1 question 63 discussion

D is correct: "All signaling between the Cisco Expressway-E and the external endpoints must be encrypted and depending on the endpoint software version, traffic must also be authenticated with certificates" "The communication between the Cisco Expressway-C and the Cisco Expressway-E must always be encrypted and authenticated using server certificates from both servers"

D. Cisco Expressway-C, Cisco Expressway-E, and endpoints outside the enterprise must be the answer.

Public DNS (External Domains) The public, external DNS must be configured with _collab-edge._tls.<domain> SRV records so that endpoints can discover the Expressway-Es to use for Mobile and Remote Access. You also need SIP service records for general deployment (not specifically for MRA). Domain Service Protocol Priority Weight Port Target host example.com collab-edge tls 10 10 8443 expe1.example.com example.com collab-edge tls 10 10 8443 expe2.example.com example.com sips tcp 10 10 5061 expe1.example.com example.com sips tcp 10 10 5061 expe2.example.com https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/expressway/config_guide/X14-0/mra/exwy_b_mra-deployment-guide-14/exwy_m_requirements-for-mra.html

It should be D MRA requires secure communication between Expressway-C and Expressway-E, and between Expressway-E and external endpoints. As per tech note https://www.cisco.com/c/en/us/support/docs/unified-communications/expressway/118798-technote-cucm-00.html

Correct answer Option A. MRA requires secure communication between Expressway-C and Expressway-E, and between Expressway-E and external endpoints https://www.cisco.com/c/en/us/support/docs/unified-communications/expressway/118798-technote-cucm-00.html#anc6

Media encryption is enforced on the call legs between the Expressway-C and the Expressway-E, and between the Expressway-E and endpoints located outside the enterprise.

A is correct