Technical White Paper
As part of the Microsoft Operations Framework, deploying and managing Enterprise Voice entails making service improvements to decrease costs, increase efficiencies, and provide better user experience. After consolidating PBX sites, improving data-center infrastructure, and deploying Microsoft Lync Server 2010 Enterprise Voice, users experienced intermittent performance and call quality issues across the organization.
To deliver the best service quality, Microsoft IT initiated a quality improvement project for Enterprise Voice. By investigating upstream and downstream service dependencies, Microsoft IT isolated root causes in the underlying network, user practices, and configuration. Through a systematic remediation of root causes, practicing proactive monitoring, and reporting on system metrics, Microsoft IT continues to improve Enterprise Voice performance for more than 100,000 users.
http://technet.microsoft.com/library/jj650858.aspx