peak power vs average power

When defining power handling capability of Tx/Rx switch module, what is the specification?
For example, peak power= 100W, Pulse width = 20uS, Pulse Repetition Rate =5kHz, mutiply pulse width by pulse repetition rate to get duty cycle. Duty will be 10%.

So,when I describe the power handling capability, peak power 100W or average 10W, which is right?

Depends on. For a semiconductor switch, the peak power matters in any case. For a mechanical relays, you'll primary care for average power, in addition for peak voltage (risk of electrical breakdown), shouldn't be a problem with 100 W.