I haven't sniffed the data yet to see what's going on - but it's my understanding that the "switchport voice vlan" command works in conjunction with CDP. When a phone is detected, the switch establishes a 'lite' trunk with the phone, passing both voice and data VLANs.
Is this trunk maintained without any BPDUs? How does that work, exactly?
If I have BPDUGuard on my access ports, does it just 'ignore' bpdu's related to Voice-VLAN related trunks, or does this trunk really exist without BPDUs?
if so... how?