Abstract: A method, system and computer program for transferring packets between devices connected to a PCI-Express bus of a computer. A selected pair of devices, such as for example a root complex device and an endpoint device or a pair of endpoint devices, connected to the PCI-Express bus, are configured to transmit/receive data with their respective maximum payload size (MPS). A packet, such as for example a read completion packet, a write memory packet or a message request packet, can then be transmitted from the source device to the destination device. If the source device MPS exceeds the destination device MPS, the packet can be divided into a plurality of sub-packets. Each of sub packets has a maxmimum payload size based on the MPS of the destination device. The sub-packets can then be transmitted to the destination device so that the packet can be delivered to the destination device.