A standalone Storage Controller with PCIe Multi-Mode capability that can be configured as PCIe Root-Complex (RC), an End-Point (EP) or a bridge (BR). In EP mode, the Storage Controller acts like a regular PCIe slaved controller which is connected to a PCIe Root-Complex provided by a Host via a PCIe port. While in RC mode, the Storage Controller acts as a PCIe configuration and management entity, a Host acting as a PCIe Root-Complex, which an add-in card or chip can attach to via a PCIe port that is provided by the Storage Controller, supporting any type of Network Device Interface, without an external Root-Complex. While in bridge mode, the Storage Controller can act as a transparent or non-transparent bridge with either a Root-Complex or End-Point port for the internal connection to the bridge.