Netscope: Traac Engineering for Ip Networks

Managing large IP networks requires an understanding of the current traac ows, routing policies, and network connguration. Yet, the state-of-the-art for managing IP networks involves manual connguration of each IP router, and traac engineering based on limited measurements. The networking industry is sorely lacking in software systems that a large Internet Service Provider (ISP) can use to support traac measurement and network modeling, the underpinnings of eeective traac engineering. This paper describes the AT&T Labs NetScope, a uniied set of software tools for managing the performance of IP backbone networks. The key idea behind NetScope is to generate global views of the network, on the basis of connguration and usage data associated with the individual network elements. Having created an appropriate global view, we are able to infer and visualize the network-wide implications of local changes in traac, connguration, and control. Using NetScope, a network provider can experiment with changes in network connguration in a simulated environment, rather than the operational network. In addition, the tool provides a sound framework for additional modules for network optimization and performance debugging. We demonstrate the capabilities of the tool through an example traac-engineering exercise of locating a heavily-loaded link, identifying which traac demands ow on the link, and changing the connguration of intra-domain routing to reduce the congestion.