The subsidiaries, Verizon Services of Arlington, Va., and Verizon Laboratories of Waltham, Mass., say that holds patents for how calls are completed, monitored and authenticated.
The suit, filed today in the United States District Court for the Eastern District of Virginia, in Alexandria, Va., alleges that Vonage Holdings and Vonage America are using Verizons inventions on a continuing basis.
According to a copy of the complaint, which was provided to eWEEK by Verizon, the suit asks for the court to issue an injunction against Vonage that would prevent the company from using the patented technologies, and it asks for financial damages for past use.
The suit points out that Verizon not only invented the technologies, but has commercialized them in its VoiceWing product line that competes with Vonage.
A few patent suits have been criticized recently because the companies holding the patents were not actively using them.
The technologies Verizon claims Vonage is infringing include gateway interfaces between VOIP (voice over IP) networks and the PSTN; billing and fraud detection; call services including call forwarding, follow-me functions and voicemail; and VOIP over Wi-Fi.
The suit also points out that Vonage does not currently hold any patents for this technology.
"Its interesting that this happened after Vonage went public," said attorney Timothy C. Meece of the Chicago intellectual property law firm of Banner & Witcoff.
Meece said that he has a significant amount of experience in defending and asserting cases like this one.
"This is the first company that Verizon has asserted these VOIP patents against," Meece said.
Meece added that hes not sure how much success Verizon will have with its suit.
"Twenty-one to 24 percent are won by patent owners," Meece said, noting that there are at least 28 different defenses that can be fatal to Verizon. "Its more likely that Verizon will lose," he said.
On the other hand, Meece said that Verizon has a lot going for it.
For one, he said, the company has very deep pockets, and for another, they have a lot of patents.
"Going in its favor are the number of patents, different aspects of VOIP," he said, "and they have a lot of money, so they can afford to assert their patents."
Neither Verizon nor Vonage will comment on the details of the suit, although Vonage has admitted in a press release that it has been sued.
The company has also said that it believes that its not infringing on any patents.