equires minimum 2500kbps on the lub link. The obtained bandwidth saving is 16%. Impact of MDCR Settings for UBR+ VP/VC This part discuses the influence of MDCR settings of ATM UBR+ VP/VC on the overall performance, based on the results of the traffic separation scenario in the above example shown in Figure A.23. As the PCR of CBR VP for transport of the Re199 traffic is fixed to 1600kbps, the MDCR of UBR+ VP ( MDCR = the total lub link rate - allocated bandwidth on Rel99 path) for transmitting the HSDPA traffic varies from 0kbps up to 1400kbps. It be observed from Figure A.23 that with the increased MDCR rates the end user application performance is improved considerably: the normalized application throughput is increased from 11% to 95%. Because with a higher MDCR rate, there is more bandwidth reserved for HSDPA traffic, and therefore the performance is better. Besides the improvement of application performance with a higher MDCR setting, the network performance is also enhanced. It is observed that RLC delays, cell discard ratio, number of TCP retransmissions are all decreased when MDCR increases. But on the other hand, the link utilization drops down due to a higher lub link bandwidth caused by larger MDCR rates is configured to transfer the same offered traffic. Therefore, MDCR should be chosen as a compromise of the system performance and the lub link utilization. That means, MDCR rate should be set properly to achieve the maximum link utilization while stratifying the QoS target. Moreover it is observed that the application performance is much more sensitive to the MDCR setting than transport network performances. When MDCR is larger than 500kbps (i.e. lub link rate = 2100kbps), the transport network performance such as cell discard ratio, TCP retransmissions, has been improved drastically. And afterwards, with further increased MDCR rate, the pace of the improvement is reduced and becomes more stable. But the application throughput is still quite low with 500kbps MDCR rate: only 46% of normalized applicati