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New Member

One way audio between Cucm and CME on VPN

dear all

we have configured CUCM 9.1 and 2911 router as gateway on HO and configured soft VPN on the same router, we have uc 540(CME) on remote site, now calls between HO and UC 540 is totally fine,but when we connect through VPN and calls to Remote site (CME) we are having one way audio we are enable to hear remote site (uc 540), on the remote site we are sing SIP phones SPA 504 and 525.and on HO we are suing Csico communicator and cisoc 7945 phones.


kindly help me to resolve the issue as soon as possible.






You have to verify routing on

You have to verify routing on all your devices. Make sure that your VPN can reach both sides CME and IP Phones.



HTH Regards, Yosh
New Member

i have double checked there

i have double checked there is no duplication of IP, well i can ping remote IP's all from vpn and HO, well one thing i tel you i have added gateway to my CUCM through VPN tunnel IP of CME, and onn CME inside interface is vlan 1 , and on tunnel ip i have bind srcadress of tunnel for h3232 communications.





Cisco Employee

Hi,For one way audio issues,


For one way audio issues, apart from the normal ping tests you need to endure that there is no device / config blocking the RTP/UDP ports. You can take packet captures on the site where there is no audio and check if the RTP stream from the main site is actually reaching it or not. We can follow a hop by hop approach to track it to see where the RTP stream is lost.



New Member

We had this issue a few

We had this issue a few months ago after a network engineer mistakenly duplicated a loopback IP address on a remote site router.  After changing the IP, suddenly had two way calls again.