There is currently a strong trend towards embedding Internet capabilities into electronics and everyday appliances. Most network controllers used in small appliances or for specialized purposes are built using micro controllers. However there are many applications where a hardware-oriented approach using Application Specific Integrated Circuits (ASICs) or Field Programmable Gate Arrays (FPGAs) is more suitable. One of the features of FPGAs that cannot be integrated into ASICs is runtime reconfiguration in which, certain portions of the chip are reconfigured at runtime while the other parts continue to operate normally. This feature is required for network controllers with multiple data transfer channels that need to preserve the state of the static channels while reconfiguration is taking place. It is also required for controllers with space constraints in terms of FPGA resources or time constraints in terms of reconfiguration times. This thesis explores the impact of partial reconfiguration on the performance of a network controller. An FPGA-based network controller that supports partial reconfiguration has been designed and constructed. Partial bitstreams that can configure certain channels of the network controller without a ecting the functioning of others have been created. Experiments have been performed that quantify the manner in which, the performance of the controller can be changed by loading these partial bitstreams onto the FPGA. These experiments demonstrated the advantages of using partial reconfiguration to change network-related parameters at runtime to optimize performance of the network controller.