The dilemma for American carriers and service providers that want to buy the most up-to-date type of 4G LTE network equipment is that wholly U.S.-based vendors are virtually non-existent, and one of them, Lucent, merged with France's Alcatel in 2006. That leaves Nokia Siemens Networks and Ericsson, both European firms, along with Huawei and ZTE, plus a handful of much smaller "others" involved in mobile infrastructure. The market is large in terms of revenues but the customers buying these wireless infrastructure systems are limited. Huawei is strong in wireless in Asia, Africa and Latin America, Rebello says, while "Cisco is strong in the enterprise space but not in the carrier-grade space."

Another security company executive, SSH Communications Security CEO Tatu Ylonen, observes that Huawei and ZTE have come to control may key 4G patents as leading telecom equipment makers. Alluding to the dire warnings about the risks ascribed to Huawei and ZTE in the U.S. House Committee report, Ylonen says, "While there are some risks, shutting them out carries its own risks. One should always have multiple layers of defense in a critical system against malicious code, bugs and bad operational practices."

Still, Mike Ahmadi, vice president of operations at San Francisco-based risk analysis and security planning firm Granite Key LLC, puts some credence in the warnings in the Congressional report about Huawei and ZTE.

"Would this be safer if it were made in the U.S.? Ostensibly, yes," he says. But his sense of assurance about that derives as much from the level of control that could be exerted by anyone in the U.S. on a legal and technical level, while China is distant, with a different corporate and governmental structure in general. Ahmadi says he has encountered evidence of backdoors on network equipment that was provisioned in China, so he doesn't think the whole idea of spying this way is far-fetched at all.

Ellen Messmer is senior editor at Network World, an IDG publication and website, where she covers news and technology trends related to information security. Twitter: MessmerE. E-mail: emessmer@nww.com.