**3. End-to-end IP QoS over UMTS**

With the evolution of the 3GPP standards, operators want to provide end-to-end QoS enabled services in UMTS. The end-to-end behavior provided by a series of network elements is an assured level of bandwidth that produces a delay-bounded service with no queueing loss for all conforming packet data (RFC2212, 1997). Assuming the network is functioning correctly, these applications may assume that (**?**):


The end-to-end QoS architecture is provided in Figure 1 in section 2. IP level mechanisms are necessary in providing end-to-end QoS services by interacting TE/MT local bearer service, GPRS bearer service and external bearer service. In this section, how to implement end-to-end IP QoS is described.

#### **3.1 QoS mechanisms in IP**

Quality of service refers to the nature of the packet delivery service provided, as described by parameters such as achieved bandwidth, packet delay, and packet loss rates (RFC2216, 1999). The Internet, as originally conceived, offers only a very simple quality of service (QoS), point-to-point best-effort data delivery. It means the network just offered available bandwidth and delay characteristics dependent on instantaneous network load. Before real-time applications such as remote video, multimedia conferencing, visualization, and virtual reality can be broadly used, the Internet infrastructure must be modified to support real-time QoS, which provides some control over end-to-end packet delays. From the view of applications, QoS is realized by adequate provisioning of the network infrastructure. In contrast, a network with dynamically controllable quality of service allows individual application sessions to request network packet delivery characteristics according to their perceived needs, and may provide different qualities of service to different applications. There are two basic types of QoS available (qodwhitepaper, 1999):


The both types of QoS can be applied to individual application 'flow' or to flow aggregates, so there are two other methods to characterize types of QoS:


Generally, we can see that there are two methods to support QoS in IP network. One is IntServ (Integrated Service), the other is DiffServ (Differentiated Service). IneServ is Per Flow based QoS control mechanism. Diffserv is Per Aggregate based QoS control mechanism. To accommodate the need for these two types of QoS, there are following QoS protocols and algorithms:

