http://www.miercom.com/dl.php?fid=20101117&type=report

Summary:

Performance Verified Report
"Microsoft Lync 2010 is the first Unified Communications product to pass the SIP Torture and Attrition Test with Miercom by achieving a record 4 million SIP calls complete without error. The evaluation of MS Lync included testing for Performance, Resiliency, and Security."

The full report is located here:

http://www.miercom.com/dl.php?fid=20101117&type=report

About Miercom:

http://www.miercom.com/?url=company/