CRITERIA FOR EVALUATING VoIP SERVICE1 In this chapter, I describe a set of important criteria that can be used to perform qualitative and quantitative measurements of IP phone or POTS phone (black phone) to black phone/IP phone voice calls over an IP network. Since a legacy POTS call, with all of its robust characteristics over an IP network, is considered to be a killer application (service) by many of the proponents of VoIP, it is recommended that a private IP network or Intranet be used for m