Oracle is suing Alcatel-Lucent, claiming the telecom equipment vendor is in violation of a number of Oracle's patents.

Alcatel-Lucent emphatically denies Oracle's claims and is charging in turn that some Oracle software - including its flagship database - infringes on some of Alcatel-Lucent's patents.

Oracle's patent-violation claims centre on a number of Alcatel-Lucent products, including the OmniTouch messaging system and the 5350 XML Document Management Server, documents show.

According to documents filed with the US District Court for the Northern District of California, Oracle first filed suit on 7 May.

The company is seeking unspecified monetary damages, as well as a declaratory judgment that it is not infringing on Alcatel-Lucent's intellectual property. Alcatel-Lucent's counterclaim calls for similar measures against Oracle.

Meanwhile, court documents state that in December 2007, Alcatel-Lucent sent a letter to Oracle CEO Larry Ellison alleging that Oracle's database and the product's Data Guard, TimesTen and Data Mining options were in violation of Alcatel-Lucent patents. Oracle's Email Center and Siebel CRM Call Center On Demand products are also in violation, Alcatel alleges.

A document that Oracle filed on Wednesday alleges that a number of the patents Alcatel-Lucent cites are invalid and unenforceable because individuals involved with the patent approval process withheld "information material to patentability" from the US Patent Office "with the intent to deceive."

An Alcatel-Lucent spokeswoman said Thursday that the company would have no additional comment. An Oracle spokeswoman did not immediately respond to a request for comment.