210-060 · Question #332
An end user reports that when making B2B calls, the calls are connection; however, no audio or video is being received by either party. Local calls work fine. Which two areas must be investigated?…
The correct answer is A. firewall configurations D. endpoint traversal mode. When B2B calls connect but carry no audio or video while local calls work fine, the problem is almost always a media traversal or NAT/firewall issue. Firewall port filtering and incorrect endpoint traversal mode are the primary areas to investigate.
Question
An end user reports that when making B2B calls, the calls are connection; however, no audio or video is being received by either party. Local calls work fine. Which two areas must be investigated? (Choose two.)
Options
- Afirewall configurations
- Bfar end camera control
- CVCS traversal zone
- Dendpoint traversal mode
- EDNS configuration
How the community answered
(26 responses)- A69% (18)
- B15% (4)
- C12% (3)
- E4% (1)
Why each option
When B2B calls connect but carry no audio or video while local calls work fine, the problem is almost always a media traversal or NAT/firewall issue. Firewall port filtering and incorrect endpoint traversal mode are the primary areas to investigate.
The firewall may be blocking the RTP and RTCP media ports even though H.323 or SIP signaling is passing through, which explains precisely why the call connects but no media flows to either party.
Far end camera control is a feature for remotely panning or tilting the remote camera and is entirely unrelated to whether audio or video media streams are flowing.
Since the calls are successfully connecting, the VCS traversal zone signaling path is already functional; the symptom points to a media-layer problem, not a traversal zone configuration issue.
The endpoint traversal mode controls how the endpoint handles media through NAT; if set incorrectly, the endpoint will not use the VCS traversal server to relay media, causing a no-media condition exclusively on external B2B calls while internal calls remain unaffected.
DNS configuration affects endpoint registration and call routing resolution; if DNS were misconfigured, the call would fail to connect entirely rather than connect without media.
Concept tested: B2B media traversal troubleshooting firewall and endpoint mode
Source: https://www.cisco.com/c/en/us/td/docs/telepresence/infrastructure/vcs/config_guide/X8-11/Cisco-VCS-Administrator-Guide-X8-11.html
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