SIP Trunk ONE WAY AUDIO

[Rohit Mangotra]

Hi,

Before I begin please see the setup that I have.

CUCM 11.5 (Publisher) --> Cisco Catalyst 3650 switch --> Cisco 2911 CUBE RTR (172.16.1.5) --> Telco (Optus)

CUCM 11.5 (Subscriber) --> Cisco Catalyst 3650 switch --> Cisco 2911 CUBE RTR (172.16.3.5) --> Telco (Optus)

I am having this issue with clients when they forward their deskphone to their mobile phone and when someone calls them (From Mobile or DeskPhone) they get ONE WAY AUDIO.

Please see attached both CUBE ROUTER and Catalyst Switch configuration. Please let me know what I am doing wrong.

Thanks & Regards

Rohit.

[Chris Deren]

This is most likely caused either by firewall or network routing issues.  Make sure your firewall allows both CUBEs IP addresses to communicate with each other and make sure both CUBEs are able to IP route between each other as well.

[Rohit Mangotra]

Hi Chris,

Thanks for your prompt reply. The Cube Routers do not go through the firewall.  It's a seperate network and pass through WAN routers to different sites (Remote Sites).

Both the Cube Routers are able to communicate with each other.

1. Ping from a Pc in headoffice to Primary Cube Router (In HeadOffice) & to Subscriber Cube Router (In Data Centre) --> Success

2. Ping from Primary Cube RTR to Subscriber Cube RTR and Vice Versa. --> Success

Any other idea?

Thank You,

Kind Regards

Rohit.

[lesantos02]

Hello,

Today we have this Problem in my company. The trouble shooting was. We collect
packets in all the route of call, basically firewall route in this case the trafic travel
for a Tunnel VPN end to end for a Cloud Service. Finally, the voice was staying in one of the firewalls Fortinet.
The problem solution: disable all feature relate to sip-alg, sip help address (set sip-helper disable, set strict-register disable )
and here. Reference: https://layer8specialist.home.blog/2018/11/23/disable-sip-alg-on-fortigate-vdom/

[MxHadi]

as dear @Chris Deren said before, one-way audio in 99% of situations, make because of network, firewall or NAT issues..
when from one end, RTP could be sent, but from other side, RTP can not be sent, this issue is happens..