The VSEC Capability register (described in Table: VSEC Capability Register ) allows the memory space of the core to appear as though it is a part of the underlying core configuration space. The VSEC is inserted immediately following the last enhanced capability structure in the underlying block. VSEC is defined in §7.18 of the PCI Express Base Specification, v1.1 (§7.19 of v2.0) [Ref 8] .