Performance and Buffering Requirements of Internet Protocols over ATM   ABR and UBR Services
  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. 
Shiv Kalyanaraman, Raj Jain, Sonia Fahmy, Rohit Goyal and Seong-Cheol   Kim