Exam 300-820 topic 1 question 13 discussion

Actual exam question from Cisco's 300-820

Question #: 13
Topic #: 1

A company has enabled ICE to optimize call flows and improve video quality between their Cisco Collaboration endpoints internally and externally.
For which reason would you see activity on the TURN server when a call is established between two external endpoints?

A. The video call is using encryption, which is not supported by ICE with CUCM 12.5
B. ICE cannot reduce the packet loss on the link
C. A STUN cannot punch holes in the firewall
D. The video call is using 4K resolution, which is not supported by ICE with CUCM 12.5

Show Suggested Answer

Suggested Answer: C 🗳️

by virtu at Feb. 5, 2021, 12:48 p.m.

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virtu

Highly Voted 2 years, 9 months ago

The answer is C "Those addresses (A, B, and C) populate the SIP SDP offer and answer as ICE candidates, and after the signaling has gone through, both endpoints will have the remote party ICE candidate addresses. It is at that point that the endpoints do a connectivity check by sending STUN messages to one another in an attempt to punch transport holes in the firewalls in order to establish media connectivity between peers." https://www.cisco.com/c/en/us/td/docs/solutions/PA/ICE/icepa125.html

upvoted 11 times

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jagifoto

Most Recent 8 months, 2 weeks ago

Answer is C. https://www.cisco.com/c/en/us/td/docs/solutions/PA/ICE/icepa125.html

upvoted 1 times

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Collabinski

9 months, 2 weeks ago

Selected Answer: C

Interactive Connectivity Establishment (ICE), defined in RFC 8445, is a protocol that combines STUN and TURN. Using ICE, endpoints can determine if there is direct connectivity between them and will then apply the STUN hole-punching techniques to keep the firewall ports opened, thus allowing for both inbound and outbound media traffic. If direct media connectivity cannot be achieved, the endpoints will fall back to the TURN server and will send their UDP traffic centrally instead of going peer-to-peer. https://www.cisco.com/c/en/us/td/docs/solutions/PA/ICE/icepa125.html

upvoted 3 times

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msully

1 year, 5 months ago

Selected Answer: C

As virtu said, the answer is C