Abstract
With the popularity of the Internet and the increasing demands of users, the Internet must provide more services to the users. However, owing to the shortage of bandwidth and heterogeneity of the current Internet, providing users with guaranteed quality of service under current Internet “Best Effort” model is almost impossible. In order to alleviate the problem, IETF has founded several working groups to find solutions for this critical issue, and proposed several standard architectures and service definitions, such as: Integrated Service(RFC1633 and RFC2210-2216)、RSVP(RFC2205-2209)、Differentiated Service(RFC2474、RFC2475)、QoS Routing(RFC2386). On the other hand, Internet 2 also has founded a working group, Internet2 QoS Working Group, which focused on setting up a QoS test environment named Qbone.Although IETF has formulated standards that can provide QoS Guarantee service over packet switching network, the worse flexibility and extensive scale of Internet makes these standards impossible to come into effect all over the Internet in a short time. For this reason, recently many researchers propose the concept of Active Networks to resolve this problem. Unlike the traditional network that only processes the header of the packet, the Active network further processes the content of the packet. Under the architecture of Active network, the data and its corresponding processing code are included in the packet. Router becomes a platform that loads and executes the processing code in the packet to process the data of the packet. Thus it can be seen that if the Internet is a programmable Active network, then new services can be provided immediately over the Internet.In this thesis, we will introduce the difficulty of providing QoS guaranteed service over packet switching network, survey current proposed solutions and standards. Furthermore, we will also survey and discuss the Active network. Finally, we will propose our framework that adopts local centralized and active reaction mechanism to support better QoS guarantee service on a per-connection basis and perform simulation to observe the performance of this framework.