According to Reuters, a November 2012 letter from the Los Alamos National Laboratory states that the lab has replaced network switches made by China's H3C Technologies because of national security concerns.
"Huawei created H3C as a joint venture with 3Com in 2003," notes CNET News' Jay Greene. "Three years later, 3Com bought Huawei's stake in the venture. And in 2010, Hewlett-Packard bought 3Com. All of which makes the decision by Los Alamos a bit peculiar. The lab apparently has chosen to remove gear made by a company owned by HP, an American company, over espionage worries. H3C, like many technology companies, manufactures products in China."
"The November 5 letter seen by Reuters was written by the acting chief information officer at the Los Alamos lab and addressed to the NNSA's assistant manager for safeguards and security," writes Reuters' Steve Stecklow. "It states that in October a network engineer at the lab -- who the letter does not identify -- alerted officials that H3C devices 'were beginning to be installed in' its networks. The letter says a working group of specialists, some from the lab's counter intelligence unit, began investigating, 'focusing on sensitive networks.' The lab 'determined that a small number of the devices installed in one network were H3C devices. Two devices used in isolated cases were promptly replaced,' the letter states."
In response, William Plummer, Huawei's vice president of external affairs in Washington, told Reuters, "There has never been a shred of substantive proof that Huawei gear is any less secure than that of our competitors, all of which rely on common global standards, supply chains, coding and manufacturing. Blackballing legitimate multinationals based on country of origin is reckless, both in terms of fostering a dangerously false sense of cyber-security and in threatening the free and fair global trading system that the U.S. has championed for the last 60-plus years."