vendors. This may, in fact, have been part of the inspiration for the "56k" modems that followed. With Internet access the "killer application" for ISDN, though, less-costly ADSL services took away market share, and ISDN for Internet access eventually went into decline. Thus analog plain old telephone service remained predomi- nant in the United States, even after ISDN became relatively ubiquitous in much of Europe and Asia. Broadband ISDN Led to the ATM Boomlet As early as 1985, the CCITT recognized that ISDN's basic rate and primary rate interfaces, over copper loops, were not sufficient for the long term. Copper was becoming obsolete; new networks would be all fiber optic, and standards would be needed. Thus began the Broadband ISDN (B-ISDN) program. Its goal was to create a standard for business and residential service at speeds high enough to support high-definition television (HDTV), which at that point was still not developed and whose actual bandwidth requirements were not yet known. A few decisions about B-ISDN were made early. The initially defined access speeds were set as 155.52 Mbps and 622.04 Mbps, SONET's STS-3 and STS-12 rates, respectively [33]. Rather than have fixed channelization, a new "fast-packet" technology would be developed for it. Initially called Asynchro- nous Time Division Multiplexing, it was soon shortened to Asynchronous Transfer Mode (ATM). ATM was not like X.25, Internet Protocol (IP), or other "Layer 3" packet-switching protocols. It was designed for high-speed implementation in hardware, basically at the physical layer. Thus it had a fixed-length block size called a cell, rather than a packet, and it did not perform payload error detection or correction in the network. Early consensus seemed to be forming for a cell payload size of 64 octets [34], with a five-octet header. But an earlier French experimental cell-relaying network had used 16-octet cells; France led a move to make the cell payload only 32 octets, which would have reduced voice packetiza- tion delay at the expens