Koon-Seng Lim

The IEEE P1520 standards initiative for programmable network interfaces

This article discusses the need for standard software interfaces for programming of networks, specifically for service and signaling control, through programming interfaces. The objective is to enable the development of open signaling, control, and management applications as well as higher-level multimedia services on networks. The scope of this effort includes ATM switches, circuit switches, IP routers, and hybrid switches such as those that provide for fast switching of IP packets over an ATM backbone. The basic ideas represented herein are in the process of development as a standard for application programming interfaces for networks under IEEE Standards Project IEEE P1520.

Realizing a foundation for programmability of ATM networks with the binding architecture

A conceptual framework, called the binding model, for the creation, deployment and management of multimedia services on ATM-based broadband networks with end-to-end quality-of-service (QoS) guarantees is presented. The key function of the associated binding architecture is to provide an open programmable environment that facilitates the easy creation of flexible services. We describe the implementation of a prototype binding architecture called xbind as a middleware toolkit for building open programmable ATM networks. Finally, we present our initial experiences with experimenting and deploying xbind over an ATM testbed and highlight some of the lessons learned.

A Binding Architecture for Multimedia Networks

An open architecture that achieves seamless binding between networking and multimedia devices is proposed. The building blocks of the binding architecture consist of a set of interfaces, methods and primitives. The former abstract the functionalities of multimedia networking devices and are realized as objects organized into a binding interface base. The methods and primitives are invoked for implementing binding applications. The binding architecture is embedded into a reference model for multimedia networking architectures that supports a clean separation between binding interfaces and binding algorithms. Communication between the objects realizing the binding interfaces is supported by CORBA. Public interfaces in the binding interface base are specified using CORBA IDL. The architecture is illustrated with a simple connection management algorithm and an example of computational binding.

Weaver: realizing a scalable management paradigm on commodity routers

While there is agreement on the drawbacks of centralized management, many approaches that address those do not scale well to large networks. We believe that effective management of future large-scale networks requires decentralized but coordinated control. In our previous work, we introduced the paradigm of pattern-based management, an approach that formalizes the use of graph traversal algorithms for controlling and coordinating lightweight agents that perform computations and data aggregation inside the network. We have shown analytically and through simulations that such a management system potentially scales to tens of millions of nodes, without significant performance problems regarding execution time and traffic overhead. We report on a first implementation designed to realize the paradigm. Our system, Weaver, consists of active nodes constructed from small, low-cost Linux computers that are deployed onto a network of commodity routers. Management programs are written in C++ and can be validated and tested for performance on a simulator before being deployed. From the design of Weaver, we derive a simple performance model that allows us to predict the performance of a management operation running on a Weaver system for a large-scale network and thus show that our system is likely to meet the scaling potential of the paradigm.

On Realizing a Broadband Kernel for Multimedia Networks

We describe a prototype implementation of a broadband kernel, an open programming environment that facilitates the easy creation of network services and provides mechanisms for efficient resource allocation. We present a service creation methodology and show how scalable multimedia network services can be constructed from a set of broadband kernel services. As a proof of concept, we built a multi-party teleconferencing service upon the broadband kernel. The service creation framework has the following characteristics: binding of different classes of transport protocols to the application, dynamic renegotiation of application QOS using the signalling network and, support for multiple resource reservation algorithms.

Developing Pattern-Based Management Programs

We have recently proposed a novel approach to distributed management for large-scale, dynamic networks. Our approach, which we call pattern-based management, is based on the methodical use of distributed control schemes. From an engineering point of view, our approach has two advantages. First, it allows for estimating the performance characteristics of management operations in the design phase. (This was the subject of an earlier paper.) Second, it reduces the complexity of developing scalable, distributed management programs, by promoting the re-usability of key software components. In this paper, we demonstrate how pattern-based management programs can be designed and implemented. We propose an object model for these programs and give a concrete example of how a management task, such as obtaining the current link load distribution of the entire network, can be realized. The example illustrates that our model facilitates writing the key software components in a compact and elegant way.

Programmability and service creation for multimedia networks

The Binding Architecture is an open architecture for building multimedia networks that must guarantee quality of service (QOS). We explore the notion of a service in the Binding Architecture and propose a conceptual model for building scalable multimedia distribution services based on it. We begin first by examining the relation between resources, their abstractions and the services that can be built from them and use this to derive a general model for binding. Based on this model, we identify a general set of capabilities required for building any multimedia distribution service. We also describe how these capabilities can be incorporated into our view of the service creation process. Finally, we augment our discussion with the description of an example service which we have developed using this paradigm.