In a world that runs on information, the loss of Cable News Network in a crisis might seem unthinkable. But today, the cable infrastructure is carrying a lot more than Animal Planet and reruns of The Brady Bunch, and like all other networks, it has its vulnerable points.
About 70 million U.S. homes receive video cable; of those, 1.3 million get telephone service over the same pipe and 5.5 million get broadband Internet access.
Traditionally a regional or local service, cable consists of 224 networks across the country. But the industry is undergoing steady consolidation as major operators such as AT&T Broadband, AOL Time Warner, Comcast, Cox Communications and others seek greater efficiencies through less redundant infrastructure.
Still, it would be highly improbable for terrorists or saboteurs to be able to deliver a national knockout punch to cable communications, industry experts said. Instead, networks in major metropolitan areas might be targeted.
"In a nutshell, the cable industry would be a difficult target, mostly because it has vulnerable points, but theyre very broadly dispersed," said Mike Paxton, Cahners In-Stat Groups cable analyst.
Satellite broadcast networks are even better protected. Knocking out a single satellite would be damaging, but few nations - much less terrorists - have the ability to knock out a target 22,000 miles above the planet. The Earth-bound distribution system would be more vulnerable, but that, too is geographically scattered.
Like traditional telecom networks, cable has hubs and spokes, with the headend serving as the equivalent of a telephone companys central office. As part of the cable consolidation, the number of headends in major metropolitan areas is declining. But they are still numerous enough to prevent an entire urban areas communications being lost in a single blow.
Across the country there are roughly 11,000 headends, Paxton said. And while security is always an issue, most of the headends are protected by little more than "an 8-foot fence and a building with a lock on the door," Paxton said.
Perhaps the biggest blow to the video world would be an attack on satellite uplink centers such as AT&Ts Headend In The Sky. The 7-year-old HITS installation in Littleton, Colo., delivers digitally compressed cable TV programming signals to cable operators around the U.S. For companies such as AT&T and Cox that operate primary cable telephony systems, the security of switched networks operated by other carriers is a concern.