Because the patent claims are so broad… Vonage would never be able to operate, nor would any other VoIP service, most likely. Vonage considers it likely that the courts will invalidate the patents.
Verizon Suing Vonage for Infringement
The Asbury Park Press reports that Verizon is suing Vonage for patent-infringement, alleging that Vonage has “appropriated the results of years of research conducted by Verizon and its predecessors.” The patents Verizon claims have been violated cover the interfaces between the old phone system and the more modern computer system mimicking it and are essential for providing VoIP phone services that mimic traditional phone service.