I have two cisco 3750Gs stacked with a trunk uplink that is caring 3 VLANs. VLAN1 (Public VLAN), VLAN 31 (Private VLAN), and the VOIP System on VLAN 50.
My understanding is that each port where im going to have a computer/phone needs to be a trunk. PC goes through the native VLAN (untagged), and the phones on the tagged vlan with DHCP options that i have in place.
I have half of the ports on vlan1 and half on vlan 31 that need to be able to access dhcp on untagged ports for PC traffic. The phones also need to be able to see VLAN 50 tagged so it jumps on the VOIP lan.
This is what I have in place for all ports (not the uplink) but does not give the PCs an IP address on the "native vlan of 31":
switchport trunk native vlan 1
switchport trunk allowed vlan 1,200
switchport trunk encap dot1q
switchport mode trunk
I am able to assign access ports to different ports and put em on any of these vlan and they work just fine. Just trouble getting the native vlan 1 and 31 to present itself as untagged when i make it a trunk port.