Riverbed Technology(s RVBD), a San Francisco-based networking company has received an unsolicited proposal from Elliott Management Corporation to acquire all outstanding shares of Riverbed for $19.00 per share in cash that values the company at a shade over $3 billion. That is a 6.4 percent premium over recent closing price of Riverbed stock. Elliot and affiliates owns about 10.5% of Riverbed.