I am a non-network newbie struggling with network issues that are way above my pay grade and would appreciate some/any advice :)
Below is a graphic representation of what the current network topology looks like.
I am trying to get the VOIP devices (on the right hand side) to operate correctly.
Where I am presently is that the softphones (Zoiper 5) can make and receive calls, and voice in both directions works perfectly – no issues at all.
The problem lies with the handset (Yealink T22P).
The handset can make and receive calls, can transmit voice, but cannot receive voice as currently shown. Although when this handset is connected to Switch A everything works as it should i.e. handset can make and receive calls and can both transmit and receive voice without any problems.
So I deduce the issue is with the TL-ER6020 but I am unclear on how to proceed. I have ‘poked a stick’ at the problem a little but do not really know how to deal with the port forwarding/dmz/nat issues in the router and would really appreciate any sort of advice and/or help.
The ports used by the VOIP/Asterisk PBX are 5160-5169 for signalling using TCP and media (ie voice) uses ports 10000-20000 and all the VOIP devices are on the same L3 subnet and the Asterix PBX server sits in the TL-ER6020 DMZ.