We just commission an STM1 link to an upstream ISP, part of the bandwidth is meant for mobile data service of a customer. The customers complain of slow download while we still have 100Mbps of capacity available. The customer did an FTP test but the result was not satisfactorily. Can any one recommend the best practice of testing this kind of connection and any possible suggestions are highly welcome on how to improve the link. The connection to upstream ISP is a BGP connection (traceroute, ping,Video streaming, etc seems to be okay).