The sun seems to be shining on Huawei, China's largest telecom-network company, which has won recent contracts in Latin America and Europe. Much of the credit for that belongs to Sun, the most trusted lieutenant of Huawei's founder and president, Ren Zhengfei. The media-shy Sun, a former government official, joined the company in 1992 and became chairman in 1998, overseeing marketing, R&D, and human resources. Revenue last year was just under $6 billion.