A method enabling I/O devices to be shared among multiple operating system domains, including first communicating with each of the operating system domains according to a protocol that provides exclusively for a single system domain ithin the load-store fabric; and second communicating with the shared I/O endpoint according to a variant of the protocol to enable the shared I/O endpoint to associate a prescribed operation with a corresponding one of the independent operating system domains. The second communicating includes encapsulating an OS domain header within a transaction layer packet that otherwise comports with the protocol, wherein the value of the OS domain header designates the corresponding one of the operating system domains; and via core logic within a swithching apparatus, mapping the independent operating system domains to the shared I/O endpoint.