Libra: Scalable Advanced Network Services based on Coordinated Active Components

This is the World Wide Web home page of the DARPA-funded project Libra project on "Scalable Advanced Network Services based on Coordinated Active Components" in the School of Computer Science at Carnegie Mellon University.


The Internet is continuing to grow at a very rapid pace, both in terms of the number of users and network throughput, and at the same time, it is trying to evolve from a best-effort network that moves data files to a sophisticated infrastructure that delivers value-added services such as video conferencing, virtual reality games, and distributed simulation. These two concurrent trends are creating significant challenges in both the infrastructure and electronic services areas. A first question is how to develop a network infrastructure that is not only highly scalable, but that at the same time has sufficient functionality such as QoS and multicast to support the envisioned services. For electronic services, the main challenge is complexity: value-added services are large distributed programs that have to execute in an unpredictable large runtime environment (the Internet), raising questions such as how to meet end-to-end service properties.

In the last five years, the networking research community has worked on active technology. The main focus on this effort has been on developing technology that allows the rapid deployment of new functionality, such as data processing or control protocols, by dynamically inserting mobile code segments, which we will call delegates, into the network. In this proposal we will demonstrate that active networking can also help in addressing the scalability and complexity issues described above. In particular, we believe that coordinated groups of distributed locally-customized delegates can implement both advanced core-network and value-added services. The key observation is that not all network nodes need to implement identical functions. By properly assigning delegates with different functionality to nodes that have different scalability constraints or that face different traffic conditions or functional requirements, and by coordinating the actions of these delegates, it is possible to implement a wide range of advanced services with a level of scalability and efficiency that so far has been impossible to achieve with conventional techniques.

We will build a set of core networking and value-added active services. Core networking services includes supporting multicast routing, quality of service for both individual flows and flow aggregates in a highly scalable manner by eliminating the need for per-flow or per group state in the core of the network. The value-added services include scalable video distribution based on dynamic replication, multicast, and transcoding, private virtual network service in which the QoS, signaling and management can be customized by the client, and a mobile client service that will allow mobile nodes to leverage the infrastructure as they move around. The value-added services will be based on a common set of middleware services that support common requirements in terms of performance, reliability and security. The project is headed by Peter Steenkiste and Hui Zhang.

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Last modified by prs@cs.cmu.edu in August 2001.