ATM service classes

I’m in a knock down drag-out with my RBOC about some ATM DS3s and an OC3. Proceeding on the advice of a Cisco engineer I requested that the circuits be provisioned with UBR+. After the Bell failed to have the circuits provisioned correctly, they installed UBR, and discovering that they could not support UBR+ I have requested that the circuits be reprovisioned with VBR-NRT. These circuits are primarily used for non time sensitive data, but may be used for VOIP in the future. What suggestions does the group have regarding selecting ATM service classes with the Bell and Cisco IOS/hardware.

As always, the expertise of the group is unsurpassed and GREATLY appreciated.

Dan Lockwood
Microsoft Certified Professional
CompTIA Network+ Certified
Cisco Certified Network Associate