Data and VoIP cohabitation

[guyber]

If we create 2 VC or PVC, one for data and one for VoIP, is it possible to do overbooking such as the data traffic could use the VoIP allocated bandwidth (if no VoIP traffic).

Thanks

[thusain]

I dont beleive there is a way to do that. You would have set up your routing in such a way that all voice traffic goes on the pvc and never on the data pvc and vic versa, so there wont be any way for you to monitor the utilization of the link and share queues on those two pvc's atleast that I know of.

[guyber]

Perhaps can I priorise the VoIP vc ?

[lindros]

I don't know if you can give precedence based on vc id such as dlci number or vpi/vci pair but you can on interface level give precedence to voip traffic through fancy queueing methods such as PQCBWFQ (create access list with udp port range of voice traffic then configure it in PQ class which gets strict priority above all else), TOS bits on dial peers among other ways. If you have say a T1 at 1.544M and have mulitple pvc's then they will all be limited by cir if Frame Relay so even if have available bw on interface level will be limited based on traffic shaping configuration. With Frame Relay for example you can set burst and excess burst high for data traffic but not for voice and give voice precedence to ensure if congestion will not get flagged DE but ok for data. With ATM I believe there is a feature called per vc queueing but if not again you may be limited by your configuration per vc.