e convergence sub-layer. This parameter does not include transport, protocol or network overhead information, and does not limit the instantaneous rate of the service flow since this is governed by the physical attributes of the ingress port. However, at the destination network interface in the uplink direction, the service is regulated to ensure conformance to this parameter. The time interval that the traffic rate is averaged over is defined during service negotiation. In the downlink direction, it may be assumed that the service was already regulated at the ingress to the network. If this parameter is set to zero, then there is no explicitly mandated maximum rate. The maximum sustained traffic rate field specifies only a bound, not a guarantee that the rate is available. CHAPTER 6 The IEEE 802. 16m MAC CPS (Part I) In addition to the legacy scheduling services, the IEEE 802. .16m supports adaptation of service flow QoS parameters. One or more QoS parameter set(s) may be defined during the initial service nego- tiation, e.g., a mandatory primary QoS parameter set per service flow and an optional secondary QoS parameter set. If multiple QoS parameter sets are defined, each of them corresponds to a specific traffic characteristic for the user data mapped to the same service flow. If the QoS requirement or traffic characteristics for UL traffic changes, the serving BS may independently perform adaptation by either changing the service flow QoS parameters or by switching among multiple service flow QoS parameter sets. The MS may also request the serving BS to perform adaptation and the BS will allocate radio resources according to the adapted service flow QoS parameters. Scheduling services characterize the data handling mechanisms supported by the MAC scheduler for data transport on a specific connection. Each service flow is associated with a single scheduling service as in IEEE 802.16m. A scheduling service is characterized by a set of service flow QoS parameters that quantify its behavior. These parameters are 