IP "telephony" vs. ATM: what is there to discuss?

This paper lists a number of issues that need to be addressed to natively support telephony services in an integrated service environment over both ATM and IP infrastructures. It presents the different approaches proposed for the network technologies. It then compares and contrasts the two solutions and concludes that IP networks are not likely to replace public telephone networks. As the current telephone networks evolve to B-ISDN, the role of IP may change from a layer 2 independent routing protocol to an addressing scheme with embedded routing information, similar to current use of E.164 addresses.