Launch power of optical signal is one of the major factors that affect the transmission quality in transparent optical Mixed-Line-Rate (MLR) networks due to physical-layer impairments (PLIs). It must be large enough to provide an acceptable optical signal-to-noise ratio (OSNR) at the receiver, but it must be below the limit where fiber nonlinearities distort the signal. Moreover, high launch power is disruptive not only for the actual lightpath itself but also for neighboring lightpaths and this effect is particularly critical in MLR. In this study, we investigate the problem of determining the appropriate launch power for provisioning of dynamic connection requests in MLR networks. By setting the appropriate launch power for each connection, we aim to maximize the number of established connections. © 2013 IEEE.