(Adds background) Aug 31 (Reuters) - Activist investment firm Jana Partners has called on internet phone company Vonage Holdings Corp to hire advisers to explore strategic alternatives, including a possible sale of all or parts of its business, Bloomberg News reported on Tuesday. Jana, which owns about 4% of Vonage as of June 30, has discussed its views with the company and fellow shareholders after a previous review of the company"s consumer business failed to result in a sale, the report bloom.bg/3BumfUO said, citing people familiar with the matter. The hedge fund has asked the company to launch a review to improve shareholder returns, it added. Jana declined to comment, while Vonage did not immediately respond to a request for comment. Shares of Vonage were up 6.7% at $14.41. Its market capitalization was about $3.4 billion as of Monday’s close. Jana has built a reputation for working collaboratively and behind the scenes over the two decades since Barry Rosenstein founded the company. Holmdel, New Jersey-based Vonage provides cloud-based business communications services, contact centers and so-called application programming interface software, or APIs, which enables apps to work with each other. (Reporting by Eva Mathews in Bengaluru; Editing by Arun Koyyur) Our Standards: The Thomson Reuters Trust Principles.