Recently, because of the expansion of TCP/IP networks, the evaluation of IP networks is being considered as a major task for network operators and administrators. As a result, many IP evaluation tools have appeared, but almost all of them can only be applied to a limited purpose. The authors have already developed an IP evaluation tool, called KITS (KDD Internet Test System) that can generate flexible load traffic. Based on KITS, the authors have now developed a new IP measurement tool. This paper describes the flexible and general IP evaluation tool, STAGE (Simulated Traffic Analyzer/generator for General Evaluation).

Today, many kinds of real-time applications are available over IP networks. It is important to measure the network performance for such applications before making use of real applications. Authors developed the general purpose traffic measurement tool for IP networks. This system can generate any kinds of traffic flexibly and calculate the network performance such as throughput, delay and loss ratio according to received packets. In this paper, the concept of this traffic measurement tool is described in detail, and several examples of network measurements are shown.

As TCP/IP networks develop, various type of applications or services are appearing. Especially, many people want to use real time multicast applications over TCP/IP networks like a TV conference system. Most of the current TCP/IP networks, however, still do not support QoS guarantees using RSVP, so that they provide only a best-effort service. Therefore, such real time applications must control data transmitting rate by the network or receiver's condition. However, it is difficult to control data rate over a multicast session, since every receiver on a multicast network does not necessarily have the same environment. To solve this problem, the authors proposed a locally adaptive control intermediate system. This paper describes a rate-adaptive real-time multicast system with locally adaptive packet flow control.