MiVoice Business call transfer issue without MBG

[klindqvi]

Hi All,

I'm new to MiVoB and to this forum, and very glad to be here.

I have a setup with MiVoB is connected to a carrier SIP Trunk without an MBG.
When I receive a call from pstn and then try an attended transfer back out to pstn, the call connects, but audio is lost.
My MiVoB and deskphone used to initiate the transfer are behind NAT.

I suspect I have problem either with nat/firewall or with my MiVoB setup/architecture.

Since MiVoB doesnt anchor the media in itself -  I am wondering that which RTP endpoint should I consider is connecting the two call audio streams together with the attended transfer without MBG? I consider options:  Lan phone, upstream pstn switch, other e.g. SBC.

I have recognized that the endpoint that connects the RTPs might affect the firewall configuration.
 
Thank you in advance.

[ralph]

It's a world of grief without having some type of SIP proxy, i.e. MBG.
In my experience, all one way audio is always something with the network. 
The audio travels from end point to end point.  The PBX only sets up the call. If end point "A" can't route to end point "B" then there is either no audio or one way audio depending on who can't reach who.

The first thing to check is that both end points have IP routes to each other or are not blocked by firewall.
In your case, NAT will probably ruin everything so you may have to break down and get an MBG.

Ralph

[klindqvi]

Managed to sort the previous problem, it was caused by asymmetric route and nat issues.

Follow up question to the same topic would be that is there a way configure my MiVoB to use the ISP public IP address in SDP offer?
I see now the SDP c-row is populated with private IP which I use in LAN, but I would need my device to signal the public WAN IP.

[lundah]

Managed to sort the previous problem, it was caused by asymmetric route and nat issues.

Follow up question to the same topic would be that is there a way configure my MiVoB to use the ISP public IP address in SDP offer?
I see now the SDP c-row is populated with private IP which I use in LAN, but I would need my device to signal the public WAN IP.

No, this is what the MBG is for.

[johnp]

Should not the Alternate Destination Domain settings under the peer make a difference?