We use Dell switches on our small network. We are planning to install a new VoIP system to replace our old digital phone system. The boss does not want to run new cabling for the new VoIP phones but wants to tether the workstations off the phone handsets; i.e. the workstations will connect to the phone VoIP handsets and that will then run to the wall plate with one network cable. He wants separate VLANs set up for the workstations, the new phones and the servers. We have two VMWare ESXi hosts on-site that each hosts a few small VM's, including a domain controller that also runs DHCP for the network.
I am familiar with setting up VLAN's using dedicated switch ports to separate VoIP and data traffic but since the workstations will be tethered to the phones I am uncertain how to proceed. Also, the DHCP server needs to be able to offer IP address leases from different IP address pools depending on which VLAN the devices belong to.
Can anyone help me by explaining how I should set up the VLANs?
1. Do I still configure VLAN's on the switches themselves? How do I assign port membership because I have two different devices linking in using the same physical port?
2. How do I define a DHCP scope specifically for use by each VLAN on the domain controller?
3. What configuration needs to happen on the workstations and server VM's to link them to the "workstation" and "server" VLANs?
4. Sake of interest: why would you use VLANs in this case and not just assign different IP subnets with DHCP MAC reservations for the devices; seems simpler?
Any help would be greatly appreciated.