 the data paths through the network. If there is no adequate bandwidth available on the path for a new traffic flow or connection, the request of the new connection has to be rejected. The relevant QoS is the connection reject ratio (see section 4.1.2.1). Additionally, a Bit Rate Adaptation (BRA) algorithm (see section 3.3.4.3) can be used for the transport of packet-switched traffic in the UTRAN for an effective utilization of the bandwidth resources. BRA dynamically adapts data rate (i.e. radio access bearer) per user flow according to its transmission activity and the available resources in the network. Another type of resource control approach is to employ policing entities such as rate limiting at the network edge to restrict the amount of traffic, which is entering the network. It should be noted that connection admission control works on a per-flow basis (a flow is either accepted or rejected), while policing is done within a traffic class on a per-packet basis (packets are dropped whenever the respective traffic exceeds a certain threshold). The impact of the applied resource control functions in the network need to be considered for dimensioning. Whenever a type of per-flow CAC scheme is used, a blocking model shall be applied to dimension the network. The application of a BRA function can improve the utilization of the network resources, but also leads to a varying data rate per user flow and hence results in a bursty traffic property. With policing entities at the network edge, the traffic aggregates can be kept from exceeding per-class rate limits. Thus upper bounds can be given for the bandwidth requirements of such an aggregate within the network. But employing policing also leads to unwanted service degradation on the active flows. 4.2.5 Routing and Traffic Engineering In order to achieve higher QoS, based on a given network infrastructure and a certain traffic load situation, a network service provider has the possibility to better distribute the traffic in the network by performing routing and tr