The phone technician has all the answers on everything from dial tones to digital subscriber lines. Today he comes up empty. "I think I know where it is. I'll make inquiries." A pause. "You want to go there?" Yes. "I don't know. We're allowed to show what's behind the curtain?"
Behind the Curtain. It's a joke
No yellow brick road, no Emerald City. A wizard somewhere pulls wires at the Internet's center. For all but a handful of 70 million users the Net is conceptual space beyond the screen, somewhere down the wire. Because it's oblique, dispersed and unfathomably complex it's known only as data railroads and information superhighways, big pipes and plumbing. Engineers and technicians making the network run use metaphor. Where does data really go? Drawn on a white board, after a certain point it disappears into the cloud. The Internet is no ethereal construct. Its tangible body exists anywhere electronic devices talk to each other over public networks in the digital language TCP/IP. It's as close as your home computer, modem and cell phone, and as distant as a satellite 22,000 miles above Earth. Hidden middle space isn't really all that hidden. To see the Internet's physical core stand at the corner of University Ave and Bryant St in downtown Palo Alto, California. It's right there between the drugstore and the bakery. No sign identifies the 3-story granite and sandstone building as the Middle of the Internet. No sign marks 529 Bryant St but 8-inch brass letters spelling out "Digital."
This is Compaq Computer's Palo Alto Internet Exchange (PAIX), one of 75 network access points worldwide where the Net's great data rivers converge. 3 of the 12 major network access points, a k a public Internet exchanges, in the U S are here. Besides Compaq's Palo Alto facility (Compaq acquired Digital Equipment June 1999) Silicon Valley's other hubs are the Pacific Bell Network Access Point (with equipment spread over 6 cities) and Mae West, MCI WorldCom's Metropolitan Area Ethernet installation in downtown San Jose. Similarities between PAIX and ordinary office buildings end at the lobby where visitors sign in, receive ID badges and wait for escorts. Everyone without exception is accompanied by a Compaq employee at all times. PAIX general manager Laura Hendriksen doesn't usually do escort duty. Today she ushers a writer through 4 layers of security doors and finally into the heart of the Net, one level below the street. Like many network people Hendriksen's not especially given to poems. Hers is a world of pipes and peers, feeds and speeds. Standing before the last locked door to the equipment cages at the center of the exchange, she talks of the 70-year-old building's history. "Most people working here know this was a phone company central office, the center of things back then. That's how it is again as if we brought the building back to its historical roots. We think that's cool. Customers do, too."
Cool is precisely what exchange designers had in mind building it in 1996. Other Internet exchanges were dank, depressing vaults, rows of equipment racks jammed into cages of cyclone fencing and two-by-fours. PAIX's equipment cages too are aesthetically correct. Museum-quality pin spots snake along the open ceiling. No longer would the Internet's heart resemble a steamship's boiler room. This would be the first-class deck right down to the highly buffed blond wood of the doors and the sleek fit and finish of the cages. No expanse of fine wood or filigree could make visitors forget they're inside a vast machine. For those unaccustomed to the highly regulated (temperature-controlled, dust-filtered, video-monitored) world of PAIX the most striking aspect is the low hum of 1000 tiny equipment fans. PAIX, like all other network access points, functions as a hub airport for data. ISPs from across the U S and the Pacific Rim pay $2,500 - $80,000 a month tarmac space and baggage-handling. Compaq facilitates cargo transfer between carriers. PAIX requires clients to have a speedy ramp (at least a 10MB-per-second Ethernet port) to the shared central switch connecting all carriers. Companies can also make side deals to route data directly between their cages, bypassing the central switch.
The largest of the 64 data airport tenants are Tier 1 carriers such as UUNet and AGIS - national and international ISPs leasing high-speed lines from long-distance phone companies to form the backbones of the Internet. Next are smaller regional and local carriers. Although smaller players have space at the airport and exchange privileges they often pay their larger brethren to carry their data. Unlike most other major network access points PAIX also rents space to content providers. A manufacturer or shipper needing ready access to many airlines may locate a warehouse by an airport. Likewise 9 large Internet content firms park servers at PAIX, directly accessible to networks. Household names pumping data through PAIX include PointCast and Alta Vista.
Tenants share a room the size of a basketball court, partitioned into cages each holding 3 - 25 coffin-sized equipment racks. Although some racks are almost empty, all 218 are rented. There's a waiting list for space. Early next year Compaq will add 185 more racks and expand PAIX onto the building's first floor. An intricate latticework of precisely tied cables connects routers and servers in the racks to data pipes running along the open ceiling. Really big pipes - 13 ultra-high-capacity fiber-optic lines phone companies lease to the largest ISPs - carry a combined total of 26.52 gigabits per second, equivalent to 1/2 million home modems going at once.
In a small room 10 ft removed from the main cages Hendriksen points to 3 bright orange plastic tubes coming out of the basement wall. 2 of the conduits, the size of vacuum cleaner tubes, continue on to a rack of equipment breaking data lines down into smaller lines. The last orange tube, containing outdated copper wires, stops one foot inside the basement wall, crudely severed with a hacksaw. Like a weed-choked wagon trail alongside the interstate, it's of historic interest only and leads nowhere. As a systems failure or delay at one hub airport can disrupt traffic across an airline's entire operation, what happens at PAIX is critically important to all clients. Unless companies buy rack space at many exchanges, one problem with a single piece of equipment here can effectively take an entire ISP and all its clients down. For network technicians who install and maintain the equipment the cage city is a 24/7 culture. When your entire company's fate hangs by a couple of OC-3 fiber-optic conduits you don't break for dinner or sleep or anything until the problem is solved. By the elevator, just outside the main cage room, is a spartan alcove with 3 plump upholstered chairs and a pair of oversize monitors displaying system stats and security information. Here out-of-town network plumbers camp out, sometimes for days. People jump on planes with no thought where they'll stay once they're here. Hendriksen points to a cage one aisle removed from the main drag. "Those 4 technicians from NetRail in Atlanta are expanding their equipment. They've been at it since 9:30 last night." In the lounge the only evidence of human habitation is 3 empty Pepsi cans and a John Le Carre novel.
Without cooperation and free data exchange between networks the Internet would not be. Cooperation today is different than when the Net was an alliance of university networks. At exchange points many carriers sign treaties enabling them to trade data freely with all other signers. Likewise the exchange is a competitive marketplace where carriers cut side deals to exchange traffic one-on-one. Internet service is a dog-eat-dog business. Nowhere is that more evident than here, where companies routinely place mission-critical equipment in plain view of their most bitter rivals. "I don't think of this place as particularly tense. We take lots of steps to make sure people behave." So far there's no instance of an overzealous tech "accidentally" fouling a neighbor's wires. "Escorts take care of malicious tendencies anyone might have. Anyone going into a cage is escorted. We've had people say 'We tested your security. He went into the common-area cage and he put his thumb on my router unchallenged.' That's the level of silliness we're talking about."
Think of an airport so competitive airlines go to elaborate lengths to disguise their planes' markings and keep flight schedules secret. At PAIX many equipment racks are anonymous. Internet Protocol numbers (numeric tags identifying equipment to the rest of the Internet) are blacked out. "We've had people go over the line, taking too much interest in stuff a couple racks away from theirs. Escorts handle that. It's a game. Most ISPs can tell who others are by looking at how they rack their equipment and what's in the racks." Few human touches soften the mood. On one ISP rack technicians post smiling life-size cardboard cutouts of staffers. Another firm installed a Christmas tree. In the beginning stuffed animals were allowed in cages to give it a zoo-like feel. It didn't work. Safety required the animals be a certain type of cloth and only brightly colored.
In the basement one machine sits apart from the city of cages, in its own room, with its own security layer. This is the GIGAswitch, the great sink to which all the data rivers great and small must flow. With its cables and ports the shared central switch looks not entirely unlike a phone switchboard out of a bygone era, an artifact from when this building was young. This is it, the very crossroads of the wired world. It's no metaphor. It's real - the molecules of the digital world are millions of pulses of white light moving through the switch every second. Hendriksen smiles indulgently when visitors kneel, placing a hand on its face.
"Is this it? The very middle?" "You could say that."
Until April 1995 the Internet's backbone was under the auspices of the National Science Foundation. With 4 government-sanctioned Internet exchange points and 2 private ones, network topology was a simple string map. When competing commercial carriers took over the backbones, maps and routes became much more complex. Today much traffic that used to flow through public exchange points is routed through private interconnections. These private peering arrangements between ISPs can take place anywhere transactions are mutually convenient. Because of secrecy involved in peering agreements it's impossible to know how much is truly shunted away from exchanges. Consensus estimates 2/3 of Internet traffic today doesn't flow through common central switches of public exchanges such as PAIX, MAE West and PacBell. The string map becomes a loosely woven fabric. Where there were once 6 grand junctions are now hundreds of smaller ones never appearing on maps. If the trend toward private one-to-one exchanges continues at the current pace there'll soon be no middle. When the center disappears piece by piece, line by line into 1000 unmarked equipment closets the Net shall truly be hidden - unmappable, unknowable.