Comments Monday by Internet pioneer Vinton Cerf raised the question, as he condemned the industry's reluctance to adopt the latest version of Internet Protocol, the system for assigning Net addresses that are the numerical reference points for any computer using the Internet. If no more addresses are created, eventually, no more sites will be able to be added to the Internet. Even for something as simple as browsing the Web, a computer needs its own IP address. Who is to blame for Net congestion? ISPs blame the Baby Bells and the Bells blame - well, you guessed it. Cerf, who carried out early work on TCP/IP at Stanford University, and is now MCI's senior vice president of Internet architecture and engineering, said an onslaught of wired appliances is set to swamp the Internet years earlier than expected. Industry experts and the engineers that keep the Net running agreed that sticking with the version of IP currently in place-Version 4 -- will lead to serious turmoil in a few years' time, maybe as early as 2003, as Cerf predicts. But they don't expect router makers, Internet service providers, or their corporate customers to take any action until a crisis hits. "Nobody just upgrades because it's a nice idea, it just doesn't happen," said Maribel Lopez, an analyst with Forrester Research Inc. "People have still got Year 2000 problems, and vendors want to find ways to sell their gear today. This is not something they feel the need to pursue." Lopez said that the Year 2000 problem, which has major corporations spending millions of dollars to patch up their old computer records systems before the millennium hits, is the model for how business technology generally gets upgraded. That is, in response to a crisis. "It's kind of a chicken-and-egg problem," said Zona Research analyst Clay Ryder. "Fuel-efficient cars didn't sell until 1974. And what happened in 1973? The oil crisis." The problem: IPv4, designed 20 years ago, can only handle a finite number of IP addresses. After they're used up, another system will have to be put in place before more addresses can be created. IPv6 accommodates many more addresses by using a 128-bit addressing scheme, as opposed to IPv4's 32-bit system. But an upgrade would mean altering the software in every router on the Net-a complex and expensive task that Internet backbone providers such as UUNET and AGIS are not yet willing to tackle. So why aren't corporations, top-level ISPs, or router-makers worried? For now, stopgap measures have been put in place that extend the number of users supported by the same number of IP addresses. One such workaround, for example, is network address translation, which allows computers within a corporation to share a small number of addresses. "What has stalled IPv6 was that people came around with reworks, so that you could still use your system with v4. If that had not happened, people would be like, 'Yeah, I want (v6) NOW!' " said analyst Lopez. But as Zona's Ryder puts it, using such workarounds only "forestalls the inevitable." And waiting for a crisis to overhaul IP could mean some nasty technical side-effects. "Sometimes you don't know things are going to work until you try them," said Harold Willison, an AGIS engineer. "It looks good on paper, but is the equipment everybody's using going to work with it? Or it might work fine on your network, but if you're not going to be able to connect to everybody else's networks, that's no good. "I think they should at least get a working model out there so when we do need it, we know it works, instead of waiting until the last minute, which is how things have been done in the past," Willison said. Elated stories: Net needs fatter pipes - Worldcom Net won't have meltdown - report 56K modems tipped to dominate Net More News | ZDNet