Although active networks have generated much debate in the research community, on the whole there has been little hard evidence to inform this debate. This paper aims to redress the situation by reporting what we have learned by designing, implementing and using the ANTS active network toolkit over the past two years. At this early stage, active networks remain an open research area. However, we believe that we have made substantial progress towards providing a more flexible network layer while at the same time addressing the performance and security concerns raised by the presence of mobile code in the network. In this paper, we argue our progress towards the original vision and the difficulties that we have not yet resolved in three areas that characterize a "pure" active network: the capsule model of programmability; the accessibility of that model to all users; and the applications that can be constructed in practice.

An active network allows applications to inject customized programs into network nodes. This enables faster protocol innovation by making it easier to deploy new network protocols, even over the wide area. In this paper, we argue that the ability to introduce active protocols offers important opportunities for end-to-end performance improvements of distributed applications. We begin by describing several active protocols that provide novel network services and discussing the potential impact of these kinds of services on end-to-end application performance. We then present and analyze the performance of an active networking protocol that uses caching within the network backbone to reduce load on both servers and backbone routers. Keywords: active networks, caching, distributed applications, networking protocols, performance. 1 Introduction Traditionally, the function of a network has been to deliver packets from one endpoint to another. Processing within the network has been limited l...

Active networking in environments built to support link rates up to several gigabits per second poses many challenges. One such challenge is that the memory bandwidth and individual processing power of the router's microprocessors limit the total available processing power of a router. In this paper, we identify and describe three key components, which promise a high performance active network solution. This solution implements the key features typical to active networking, such as automatic protocol deployment and application specific processing, and it is suitable for a gigabit environment. First, we describe the hardware of the Active Network Node (ANN), a scalable, high performance platform based on off-the-shelf CPUs connected to a gigabit ATM switch backplane. Second, we introduce the ANN's modular, extensible and highly efficient operating system (NodeOS). Third, we describe an Execution Environment running on top of the NodeOS, which implements a novel large-scale active networ...

. Active networks is a framework where network elements, primarily routers and switches, are programmable. Programs that are injected into the network are executed by the network elements to achieve higher flexibility and to present new capabilities. This work describes a novel active network architecture which primarily addresses the management challenges of modern complex networks. Its main component is an active engine that is attached to any IP router to form an active node. The active engine we designed and implemented executes programs that arrive from the network and monitors and controls the router actions. The design is based on standards (Java, SNMP, ANEP over UDP), and can be easily deployed in todays IP networks. The contribution of this paper is the introduction of novel architectural features such as: isolation of the active mechanism, the session concept, the ability of active sessions to control non-active packets, and blind addressing. Implementing these ideas, we buil...

Active networking allows the network infrastructure to be programmable. Recent research focuses on two commonly separated approaches: “capsules ” and “programmable switches”. Capsules are typically small programs in packets which flow through the network and are executed in-band on nodes receiving them. Programmable switches are network devices which offer a back door to inject code by a network administrator out-of-band in order to enhance the device’s capabilities. By combining these two approaches, this paper proposes a novel system architecture which allows both application specific data processing in network nodes as well as rapid deployment of new network protocol implementations. Instead of carrying code, data packets carry pointers to digitally signed active modules initially loaded on-the-fly, inband, from trusted code servers on the network. Packet processing runs at high speed, may access and modify the whole network subsystem and no potentially slow virtual machines are needed. Key words: active networks; application specific data processing; automatic protocol deployment; distributed code caching 1.

An active networking architecture provides the infrastructure for applications to inject user programs into the nodes of the network. This enables customization of the network nodes so that application-specific services can be downloaded into the network in the form of new protocols. In this paper

The aim of the Active Networking today effort is to design, develop and implement new communication architectures that allow rapid, safe and dependable creation, reconfiguration, and deployment of advanced networking services, protocols and management components. The Active Networking paradigm achieves this goal through the concepts of (1) self-directing data units called Capsule or Smart Packets, and (2) Open Programmable Nodes. The conjunction of these concepts will ultimately result into networks with greatly improved communication services that meet user requirements efficiently and securely. This paper reviews and evaluates two major architectures of Active Networking, the well-known Active Node Transport System (ANTS) and the SwitchWare framework. We discuss the differences between the two architectures and platforms, and feedbacks from practical experiences.

While active networks have generated much debate in the research community, on the whole there has been little hard evidence to inform this debate. This paper helps to redress the situation by reporting our experience designing, implementing and using the ants active network over the past two years. We find that ants succeeds in automatically deploying wide-area services such as routing variants that would otherwise be difficult to introduce; based on experiments we characterize the services that ants is well-suited to introduce and those that it is not. At the same time, by tightly bounding the abilities of capsules in ants, we have made substantial progress in addressing the performance and security concerns raised by the presence of mobile code in the network. For example, because it is compatible with IP and runs only at selected routers, ants provides a systematic means of using excess processing available at bandwidth-limited routers, rather than slowing core routers. Further, an...

This article describes an active network testbed, AMARRAGEbone, deployed