A repeater is a signal conditioning device that ensures a good signal to reach to and from the root complex and PCIe endpoints. Repeaters can fall into two categories: retimers and redrivers. Both are common PCIe components used to maintain signal quality of high speed links and compensate for the loss of signal quality over the traces. Figure 3-1 shows it as the dark blue box that connects the root complex and PCIe endpoint and is referred as "Repeater."