CCOpt-CTS

Hi All

I'm using to ccopt to build the clock tree. During one of its intermediate optimization steps it prints the following:-

Window Outage Statistics {Sinks: 50709; Under-delay Violations: 7702 {Worst: 0.079ns; Total: 132.771ns}; Over-delay Violations: 0}

Here 50709 depicts the total number of clock sinks, but what are these Under-delay and Over-delay violations??

Kindly explain.

Thanks in advance!