We present a novel approach to building and deploying network protocols. The approach is based on mobile code, demand loading, and caching techniques. The architecture of our system allows new protocols to be dynamically deployed at both routers and end systems, without the need forcoordination and without unwanted interaction between co-existing protocols. In this paper, we describe our architecture and its realization in a prototype implementation. To demonstrate how to exploit our architecture, we present two simple protocols that operate within our prototype to introduce multicast and mobility services into a network that initially lacks them. 1

Active networks permit applications to inject programs into the nodes of local and, more importantly, wide area networks. This supports faster service innovation by making it easier to deploy new network services. In this paper, we discuss both the potential impact of active network services on applications and how such services can be built and deployed. We explore the impact by suggesting sample uses and arguing how such uses would improve application performance. We explore the design of active networks by presenting a novel architecture, ants, that adds extensibility at the network layer and allows for incremental deployment of active nodes within the Internet. In doing so, ants tackles the challenges of ensuring that the exibility o ered by active networks does not adversely impact performance orsecurity. Finally, we demonstrate how a new network service may be expressed in ants.

The requirements for storage space and computational power of largescale applications are increasing rapidly. Clusters seem to be the most attractive architecture for such applications, due to their low costs and high scalability. On the other hand, smart disk systems, with their large storage capacities and growing computational power are becoming increasingly popular. In this work, we compare the performance of these architectures with a single host-based system using representative queries from the Decision Support System (DSS) databases. We show how to implement individual database operations in the smart disk system and also show how to optimize the execution of the whole query by bundling frequently occurring operations together and executing the bundle in a single invocation. Besides decreasing the overall execution time, operation bundling also offers an easy-to-program and easy-to-use interface to access the data on smart disks. We also present a protocol for minimizing the communication time in the smart disk based system. To measure the response times, we have developed the DBsim, an accurate simulator which can simulate the database operations for the single host-based, cluster-based and smart disk based systems. Using this simulator, we illustrate that the smart disk architecture offers substantial benefits in terms of overall query execution times of the TPC-D benchmark suite. In particular, the average response time of the smart disk architecture for the representative queries from the TPC-D benchmark in our base configuration is 71 % smaller than the response time on the single host-based system and 4:2 % smaller than the response time on the fastest cluster architecture. We also demonstrate the effectiveness of the operation bundling. 1.

this paper, we present a detailed quantitative evaluation of a smart disk based architecture. To achieve this, we compare the performances of a smart disk system, two types of cluster systems and a single host system for whole database queries. The main contributions of this paper are as follows: ffl We present how a whole database query can be executed on a smart disk system. ffl We present and evaluate a method called operation bundling for reducing the execution time of the database queries in smart disk architecture

This paper introduces a state description for mobile agent systems on ad hoc networks, allowing agents to reason about how they communicate over the agent system's underlying network. The ability to make intelligent decisions about communications allows agents to achieve their goals more efficiently, and increase the security and survivability of an agent system. One application of this model includes a formal representation of information assurance for agent messaging on dynamic networks with possibly redundant routes. We use this framework to study the "compromised host" problem -- specifically, how agents should react after an intruder has been detected. This is done by first quantifying the effect of the compromised host on the integrity of messages among agents; and then selecting a routing policy with respect to message integrity and the compromised host (e.g., rerouting to avoid the host or continuing to communicate through it). We provide examples of how this technique can be used to improve information assurance for agent-to-agent communications and information distribution in sensor networks. Empirical validation in the Secure Wireless Agent Testbed (SWAT) shows network awareness improves the survivability and efficiency of mobile agent systems.

Smart disk systems with large storage capacities and growing computational power are becoming increasingly attractive. The idea is to perform parallel and filtering-type of data intensive computations on disks, close to data, thereby offloading the host processor and increasing the aggregate system power. In this

Narrowband integrated audio/data networks require bandwidth management techniques to be implemented during congestion to provide the desired quality of service. Traditionally, congestion control schemes are applied generically and broadly at congested nodes. This can be improved by using Active Networks which provide application-specific processing of user-data at congested nodes. Each application specifies how losses to the data it is processing should occur in a controlled fashion, while maintaining the desired quality of service. In this work, the Active Network architecture is implemented for a Narrowband ATM network. Switching is provided using a software switch on a computer running Linux Operating system. Congestion control programs are inserted into the switches dynamically using on-demand loading. The effectiveness of this design is demonstrated by implementing a bit-dropping congestion control algorithm for audio coded using Sinusoidal Transfer Coding (STC), encapsulated ac...

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