There is an Issue when you use Polycom VVX and/or Trio Phones with Ubiquiti UniFi Switches: The Phones switch or jump between the Voice VLAN and the Data VLAN.

For the moment, it looks look an LLDP-MED Issue: if you reduce the LLDP Timer interval to 5, the issue is gone.

# SSH to your switch and then execute the following:
telnet 127.0.0.1
enable
configure
lldp timers interval 5

The problem with that: As soon as you reboot the switch and/or re-provisioning, that fix is gone, and you need to do it again!

However, there is a much better fix for that issue: Tell the Polycom Equipment what the VoIP VLAN is!

You have two (2) options to do so:

1. Use DHCP Options 128 and 144
2. Enforce the VLAN on the phone (Via web-interface or config File)

My personal favorite is to use both in combination, just to make sure that everything works as it should!

Here is my default LLDP configuration:

<device_net
    device.net.lldpCapabilitiesRequired.set="1"
    device.net.lldpCapabilitiesRequired="1"
    device.net.lldpEnabled.set="1"
    device.net.lldpEnabled="1"
    device.net.lldpFastStartCount.set="1"
   device.net.lldpFastStartCount="5"
/>

This is the configuration that every Polycom Phone gets deployed via a provisioning server.

I deploy the following to each phone (overwrite):

device.net.vlanId="<YOUR-VLAN-HERE>"

You can do the same via the Webinterface (Will do the same as the config above):

Polycom VLAN Setup

Set the following in the “CUSTOM DHCP OPTIONS” of your Voice Network:

USG DHCP Options

The entry needs to be uppercase and it have to end with a semicolon! The VLAN needs to be the VLAN Number, not the name!!!

Example, where the Voice VLAN for the Polycom Equipment is 33 (As you can see also above):

VLAN-A=33;

VLAN-A is the Voice VLAN (first), VLAN-B (Not in use here) is the Data (second) VLAN.

Here is my Switch Port Configration:

Switch Port

And the Portgroup Configuration:

Switch Port Group

Tested with Polycom VVX, Polycom Trio 8500/8800, and Polycom Trio Visual+. With Firmware 5.7 and 5.8.