Telefonaktiebolaget L M Ericsson agreed to acquire Vonage Holdings Corp. for $6.2 billion. The purchase price values Vonage at $21 per share, implying a 28 percent premium to Nov. 19 closing price. Vonage is a cloud-based communications provider based in Holmdel, New Jersey, with 2,200 employees throughout the United States, EMEA, and APAC. The transaction…