Yealink Forums

When a T21 calls a VP530, the calls sometimes drop. It never happens if a VP530 calls a VP530 or even if a T21 calls another T21 across locations. The drops happen roughly 50% of the time.

The failed calls are taking place across a LAN-to-LAN VPN connection and the T21 and VP530 are registered to different PBXs. If a T21 calls a VP530 on the same PBX, the calls do not drop.

I see in the Wireshark logs that the VP530 is sending H264 traffic and G711a on the voice only call and when the remote PBX receives the H264, the PBX disconnects the call.

I would appreciate any assistance in resolving dropped calls.

Hi Aboodoo,

The VPN connection is set in router or in phone?
What's the model of these two pbx?
Can you please send us the wireshark log?

Regards,
James

Hi James,

Thank you for your response. I am sending the email with the wireshark logs to support@yealink.com. The VPNs are set on Draytek Routers and the PBXs are Yeastar U100s.

aboodoo

James,

For the calls that drop there are ICMP port unreachable frames in the capture from the PBX to the video phone.

sinr

Hi James,

Any updates on this issue?

aboodoo

Hi Aboodoo,

Have you cofigured this parameter?

phone_setting.video.send_frame_request = 0

How about the issue now?

James