Rampant dynamic spectrum allocation over time leads to creation of narrow spectrum holes which can be aggregated to fulfill the bandwidth requirements of users. Even though this approach increases the throughput, it comes at the cost of degraded spectrum utilization due to a rise in the number of required guard bands. This paper proposes a framework for online defragmentation of non-contiguous channels as a way to mitigate the wastage of spectrum in channel aggregating DSA networks. The efficiency of this framework is studied through a testbed implementation and simulations.