Mitel Corporation, a producer of unified Internet Protocol communications solutions and applications, has filed a lawsuit against ShoreTel Inc. in the US District Court for the Eastern District of Texas. Mitel is alleging infringement of four Mitel patents.

In a well-quoted remark, Mitel’s Christian Szpilfogel stated pointedly that “Mitel has invested significant resources into intellectual property in support of its communications innovations, and we intend to assert our rights against those that infringe that intellectual property.”

Alongside announcing the lawsuit itself came the news that Mitel has retained the services of Fish & Richardson P.C.

The timing of the lawsuit itself was particularly bad for ShoreTel, as the defendants were just about to launch its initial public offering on Wednesday, the same day the lawsuit was filed.

ShoreTel Inc. shares had been expected to begin trading yesterday after the company’s IPO priced at $10.50 on Wednesday. The company offered 7.9 million shares in the IPO.

ShoreTel officials and legal advisors have yet to comment on the lawsuit or the IPO, which has yet to begin trading.