![]() The proposed QoS architecture is based on two important aspects: the DiffServ-based resource management scheme for guaranteeing a suitable level of QoS, and the signaling mechanisms for providing dynamic resource reservation. In particular, this work is focused on providing a scalable architecture for dynamic resource allocation/configuration when an access network (which may be QoS aware or not) requests transport to a “ QoS enabled” network. It is difficult to define static SLAs that are well suited to the user demand.įor these reasons dynamic resource allocation in a QoS domain is a very important issue. If the user changes the call parameters during the call, reducing the resource requirements, he will still pay for the unused resources ![]() The maintenance of the information about all the users introduces scalability issues In the current DiffServ framework, even if it were possible to define a static SLA (Service Level Agreement), it is difficult for a client to rely on such SLAs for several reasons: The IntServ architecture, on the other hand, is a more dynamic one and is better suited to address time-variant configuration issues but it has shown its weakness when dealing with scalability problems. Since the amount of traffic offered to the network is intrinsically variable with time there is the possibility of underutilizing the resources or overloading the network. The providers configure the network resources statically with a capacity planning study without a time-dependent optimization. The DiffServ architecture has the potential, with its Per Hop Behaviors (PHBs), to differentiate the QoS in a scalable mode unfortunately such architecture is still utilized in a static manner. A very good introduction to IP QoS topics can be found in. In addition, the MPLS (Multi Protocol Label Switching) technology is going to play an important role in this field, for example as transport backbone for DiffServ. Additional proposals consider a combination of the two approaches. Looking at the standardization effort in the area of IP QoS the two main approaches that have been proposed in the IETF are the Integrated Services (IntServ) model and the Differentiated Services (DiffServ) model. The automation of the resource allocation process and of network element configuration within a QoS network is a hot topic in the Internet community. A testbed implementation of the proposed architecture and a set of performance tests on the internal QoS API are reported. Finally the interaction of a session level signaling protocol (i.e., the SIP for IP telephony) with the QoS protocol is defined. Then a QoS signaling protocol is considered, that allows external QoS clients to dynamically access the QoS services provided by the network. ![]() This interface provides access to the DiffServ QoS mechanism available in a router and is used by the control logic running in the router itself. At the lower level, an internal interface (“Application Programming Interface”––API) in the QoS router is considered. For this scenario, a set of control plane interfaces needed for a whole end-to-end QoS architecture is defined. We consider the advanced scenario, where the QoS mechanisms can be dynamically configured to follow the applications’ need. The simplest approach is to have a static configuration of QoS and therefore no direct interaction in the control plane between applications and QoS. The “binding” of the applications QoS needs with the QoS features offered by the DiffServ networks is still an open problem. The DiffServ architecture offers a set of QoS mechanisms for IP networks. Voice, video and multimedia applications are sensitive to the QoS provided by the underlying IP network. ![]()
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