You are here

one way audio with IP phones

6 posts / 0 new
Last post
one way audio with IP phones
our network has a raspberry PBX server at one of our mountain top sites.  most of our group has a direct connection to the node that it is connected to.  a little further south is another mountain top node for us in the southern part of the valley.  I connect to this second node.  with the mountains and valleys here, we have more of 2 hub and spoke designs, and not so much "mesh"  these 2 sites are connected with a stock Ubiquiti firmware bridge,  here is the issue I am seeing.  many of us are using Cisco SPA504G IP phones.  the guys on teh north end of the county can talk to each other just fine, but If I try to contact any of them, I hear no audio coming back from them, but they hear me just fine.  I get this with 2 different phones, so I know its not the hardware.

At winter field day, we set up with a line of sight path to the Mesh node about 5 miles away and I configured 3 phones for the 3 different sites.  While logging worked great with the mesh network, the Phones were having the same issue of one way audio. this tells me that it has nothing to do with adding a few extra hops to the network. can any of you think of something I could have missed or done incorrectly when setting up these phones?
Is the mesh node your phone
Is the mesh node your phone is plugged into by any chance set to NAT mode?

If so it would likely be a port forward problem.
ke6bxt's picture
ARE you able to get two way
ARE you able to get two way audio when making a voip call using direct ip address calling How are the node(s) on the North hub connected to the node(s) on the South hub? VLAN switch, ToughSwitch, (dtd) connection, tunnel, NAT? I have had one way audio with a BOX on the internet and IP phones on the mesh with one of the nodes having a WAN connection. To fix this we needed to have static routing on the router at the BOX to route all 10.x.x.x addresses to the mesh interface.
ke6bxt's picture
PBX not BOX. %*$@#$
PBX not BOX. %*$@#$ autocorrect.
N2MH's picture
"stock Ubiquiti firmware bridge"

Can you describe what this is, what it's doing for you and what you want it to do for you?

As KG6JEI points out, if there's any mangling of sip packets, you could very well have one-way audio. Normally, the Mesh network handles sip OK, no matter how many links are involved. The key is that the packets are kept intact from one end of the connection to the other. However, if this "firmware bridge" is doing something to the packets, such as changing source or destination addresses, this could very well be the heart of your problem.

If this is truly the case and using this device is your only option, you may need to have a second pbx to serve your southern users. Connecting the two pbx's together will be an IAX type of trunk which is resiliant to this type of behavior. If you wish to pursue this solution, please contact me off-line.

One other thing comes to mind. You mention 2 different phones. Are these simply two different physical phones or are they two phones from different vendors? If you find that all phones of a common type/vendor don't work  but different vendor's phones do work, that would suggest some sort of configuration problem rather than a network problem.

73, Mark, N2MH

I started at the top of the
I started at the top of the list and KG6JEI may have had the correct answer.  I forgot that I had to reconfigure my switch, and add my other node back to the system.  I have a rocket dish for my main link and it has a NAT address on my home network.  I have a nanostation that I run services through with the DHCP server on its own Vlan.  my phone was operating through the NAT rocketdish because the nanostation wasn't connected.  I plugged the nanostation into the switch, set up tagged VLAN2 for DTD, I plugged my phone into untagged VLAN10 for my Nanostation DHCP and it is at least working locally now.  I am waiting for a phone call over mesh now to do a full test, but that is at least an improvemnt. 

Theme by Danetsoft and Danang Probo Sayekti inspired by Maksimer