Cooperative transmissions combat various fading effects in wireless communications by employing multiple antennas from different nodes to achieve spatial diversity. Virtual Multiple-Input Single-Output (MISO) is one instance of cooperative transmissions capable of achieving higher receiving SNR, which can either extend the transmission range or increase the transmission rate. While the physical layer performance of Virtual MISO has been well studied, this paper describes the Cooperative Source Routing (CSR) protocol to convert physical layer gain into network level performance improvement. With both route request and route reply control packets being transmitted cooperatively, CSR can explore routes with high cooperative diversity. We demonstrate CSR's performance through simulation and compare CSR with other protocols.