3Com 3032 Configuration Manual page 669

Benefits of QoS for the Network Service 665
Adjustable network service. If the user is ISP, by using QoS, the adjustable
network services of different priority levels can be provided to various types of
clients.
Secure network services for specific data flows. For example, it can ensure that
the multimedia data flows and voice flows sensitive to the delay will acquire
the service in time.