Google has hit back at British Telecom more than a year after the company sued Google for infringing on its patents with Android.
The search giant this week filed suit against BT in California and UK courts, arguing that BT is infringing on Google patents.
"We have always seen litigation as a last resort, and we work hard to avoid lawsuits," a Google spokeswoman said. "But BT has brought several meritless patent claims against Google and our customers - and they've also been arming patent trolls. When faced with these kind of actions, we will defend ourselves."
One of those patent trolls is Suffolk Technologies, which sued Google (and AOL) in 2012 using patents it acquired from BT.
Google's California suit focuses on four patents that cover a "method and apparatus for reserving system resources to assure quality of service," as well as a "gateway for Internet telephony" and a "system and method for connection capacity reassignment in a multi-tier data processing network system."
BT is infringing on those patents with its QoS as well as OneVoice/UCC services, according to Google's suit.
Google is seeking damages, costs, and expenses, including attorneys' fees.
BT's suit, meanwhile, covers a variety of Google services, including Google Maps, Google+, Google Music, and more. "BT brings this action to recover the just compensation it is owed and to prevent Google from continuing to benefit from BT's inventions without authorization," BT said in its suit, filed in December 2011 in a Delaware district court.