Abstract: Service message streams are sent to create sent service messages from a source across networks to a destination and receive responses to the sent service messages to create an estimate of the jitter in the travel time and a packet loss measurement at each device traversed between the source and destination. Communication with the service provider of one of the devices may estimate the quality of service across each device based upon the jitter estimate and packet loss measurement, and possibly also based upon the service message type and/or the message rate. Multiple sources may be operated at multiple sites within an enterprise. The service provider may operate agents at the source and destination to estimate two-way quality of service.