Cannot see Yealink SIP multicast - PnP

[adbe80]

Hi All,

I work for a company that has recently ordered a new 3CX on-premises solution. We will be using Yealink and maybe some older Cisco 79xx SIP phones. I have a small lab setup to trial some of the features and functionality of the system.

My lab environment:

• 3CX appliance running on virtualbox on my development laptop (windows 10, 64-bit), bridged adapter via a local ethernet port.
• DHCP server running on the development laptop
• A simple LAN, no routers, single unmanaged switch
• various yealink IP phones and conference units (T42S, T46S, CP960, CP920) + Cisco 79xx handsets with SIP firmware
• for troubleshooting purposes, a run a single Yealink IP phone

I am trying to get PnP to work with the yealink phones, unfortunately, I cannot see the multicast packets on the network with wireshark. So far I have tried:

• updating the yealink phone firmware
• ensure PnP support is enabled in the phone web config
• factory reset the phone
• login to the phone web interface, and force the auto-provisioning procedure (there is a button at the bottom)
• connect another laptop to the network and look at wireshark traces, also do not see multi-cast packets
• connect to the network on different interfaces (e.g. a USB network adapter)
• try a different switch - I have tested both a Cisco 3750 and unmanged dumb switch
• disabled virtualbox interface (there is an old bug regarding route metrics for the mutlicast address)
• tried different Yealink devices - T42S, T46S, CP960, CP920
• ping 224.0.1.75 multicast addresses to ensure the packets appear on both laptops

I checked the 3CX documentation on multicast setup, and the only thing that I cannot see on my dev laptop is multicast group registration to 224.0.1.75, however, the packets should still be seen in wireshark as promiscuous mode is turned on.

Everything else seems to work ok, the phone receives a DHCP address, announces itself via LLDP and CDP, however never sends out a SIP subscribe message. Given all of the documentation I have read I can only think that there is some kind of configuration issue on both laptops, however the fact that they can see the mutlicast pings makes it seem like they are configured correctly.

Manual provisioning works fine, DHCP option 66 also works. However for ease of setup we would like to use PnP.

Any tips??

 

[YiannisH_3CX]

Hello @adbe80

First of all make sure that the phone is running the 3CX supported firmware to avoid any issues there.
https://www.3cx.com/support/phone-firmwares/

Then make sure that the phone is in factory reset state. Phones will only send multicast on boot up and if factory reset.

The following guide can help you troubleshoot PnP issues.
https://www.3cx.com/docs/plug-and-play-ip-phone/

You could also create a port mirroring on the switch the phone is connected to and run a capture there to see what the phone is sending upon startup.

 

[adbe80]

Thanks,

Already using firmware from 3CX. I gave up in the end, our solution integrator also did not recommend PnP and instead deploys via DHCP - I would agree with them given my experience for even the most basic setup.