  The Asynchronous Transfer Mode (ATM) networks are quickly being adopted as
backbones over various parts of the Internet. This paper analyzes the
performance of TCP/IP protocols over ATM network's Available Bit Rate (ABR) and
Unspecified Bit Rate (UBR) services. It is shown that ABR pushes congestion to
the edges of the ATM network while UBR leaves it inside the ATM portion.
