When the option to use multiple PCIe* endpoints is needed, asynchronous vs synchronous communication must be determined. In the cases where synchronous communication is required, a packet switch may be the ideal solution. While more expensive than the previous solutions, packet switches have the built-in logic to control multiple PCIe lanes for simultaneous communication. Packet switching splits the PCI-Express datapath at the network level in the OSI model, offering greater flexibility to communicate to PCI-Express endpoints synchronously.
If asynchronous communication is desired between multiple PCI-Express endpoints, a PCI-Express MUX provides the necessary connectivity. A fanout buffer is required for output control of asynchronous endpoint devices.
Multiple Asynchronous PCI-Express Endpoints
The diagram below shows how to connect multiple PCI-Express devices communicating asynchronously via PCI-Express MUX.
Multiple Synchronous PCI-Express Endpoints
The following diagram shows how to connect multiple PCI-Express devices communicating synchronously.