At one of our office locations, we run a mix of voice, data and VOIP. We have taken the stance that VOIP is data and therefore should use the existing ip addressing. The way we separate voice and data is by VLAN. The data VLAN is an even number and the voice is an odd number.
1st floor VLAN88 10.10.88.x Data LAN
1st floor VLAN89 10.10.89.x Voice LAN
This way we can tie the data VLAN to the subnet and associate VLAN and subnet for the voice. We have done this for each floor in BV and intend to extend it to the remote offices also.
My concern is, if at some later stage, we decide to bring in MPLS inter-site connectivity and decide to implement QoS or 'Class of Service', giving priority to Voice over Data, would this IP schema be sufficently capable of handling that part or we might be forced to re-think this for something more efficient?
How do you guys usually demaracte data vis a vis VoIP traffic on internal IP subnets? Is it better to use a separate class of Private IP subnets altogether, e.q 192.168.*.* or 172 range of rfp 1918?