Network engineers are buzzing this week as the Internet outgrows some of its gear.
Internet providers, corporations and universities all rely on a common map of routes to send emails, videos and everything else on the Web where it's supposed to go.
That Internet atlas has thickened, and some of the machines that read it are now straining to hold all the pages.
While a precise count is elusive, many technicians are reporting that the total number of world-wide Internet routes is near or already past half a million, usually abbreviated 512K. Older network routers from Cisco Systems Inc. CSCO -0.45% and other makers can't hold any more unless they are tweaked.
The fix is simple. Engineers can buy new gear or raise their routers' memory caps and reboot. But some Web companies need to reconfigure each device one at a time, and the fallout is hard to judge given the numbers involved. The work already caused some websites to go offline Tuesday. More links could suffer in the days ahead.
The situation echoes—if faintly—the hubbub over the feared Y2K computer glitch in the late 1990s, when experts warned that systems could fail because their dating functions hadn't been designed to handle the turn of the century.
This time, Internet specialists are being careful to warn against a descent into that era's hyperbole and shrill warnings of disasters that never materialized.
Still, the issue was adding to many engineers' real-life workload as recently as this week. Website hosting service Liquid Web Inc. said that some users had trouble connecting to a portion of its customers' Web pages Tuesday until its technicians sorted out the problem.
"It's certainly an issue that pushed some of our routers over the limit," Liquid Web spokesman Cale Sauter said. "Getting to the bottom of everything took a large portion of the business day."
The Internet rests on two important directories: the Domain Name System, which tells packets of information where they should be going, and the global routing table, which tells them how to get there. When either system breaks down, some Internet addresses can get cut off from the rest of the Web.
Network engineers have been discussing the routing problem for years through mailing lists and highly technical conferences with names like the North American Network Operators' Group. Internet traffic handlers like Level 3 Communications Inc. said they bought new equipment with extra memory more than a year ago, heading off the problem before it affected users.
The problem also draws attention to a real, if arcane, issue with the Internet's plumbing: the shrinking number of addresses available under the most popular routing system. That system, called IPv4, can handle only a few billion addresses. But there are already nearly 13 billion devices hooked up to the Internet, and the number is quickly growing, Cisco said.
Version 6, or IPv6, can hold many orders of magnitude more addresses but has been slow to catch on. In the meantime, network engineers are using stopgap measures
More websites and broadband firms are likely to feel the pinch in coming days as they hit the seemingly arbitrary limit, said Jim Cowie, chief scientist at network management company Dyn. Web companies usually have slightly different versions of the digital map, so their databases will breach the 512K route mark at different times.
Newer routers can handle more than one million Internet routes, but experts say that number also could prove too low in the long run given the Web's fast growth rates.