Active networks are a novel approach to network architecture in which the switches of the network perform customized computations on the messages flowing through them. This approach is motivated by both lead user applications, which perform user-driven computation at nodes within the network today, and the emergence of mobile code technologies that make dynamic network service innovation attainable. In this paper, we discuss two approaches to the realization of active networks and provide a snapshot of the current research issues and activities. Introduction – What Are Active Networks? In an active network, the routers or switches of the network perform customized computations on the messages flowing through them. For example, a user of an active network could send a “trace ” program to each router and arrange for the program to be executed when their packets are processed. Figure 1 illustrates how the routers of an IP

Active Networks is a network infrastructure which is programmable on a per-user or even per-packet basis. Increasing the flexibility of such network infrastructures invites new security risks. Coping with these security risks represents the most fundamental contribution of Active Network research. The security concerns can be divided into those which affect the network as a whole and those which affect individual elements. It is clear that the element problems must be solved first, as the integrity of networklevel solutions will be based on trust of the network elements. In this

Active networking is the placement of usercontrollable computing functionality in the switching nodes of a network. The end-to-end argument states that functions should be placed "in" the network only if they can be cost-effectively implemented there. We argue that active networking is a natural consequence of the end-to-end argument, because certain functions can be most effectively implemented with information that is only available inside the network. We propose a performance model for quantifying the benefit of implementing a particular functionality solely in the end system versus implementing it through a combination of end system and network support. We show how the model applies to specific services, including congestion control and reliable multicast. 1 Introduction Discussions of the implementation of various functions in a communication network often invoke the endto -end argument, an architectural principle that guides the placement of functions within a distributed syste...

Active Networks carry SmartPackets which contain both data and user-specified methods to extend the functionality of switches to perform user-specific computation on the encapsulated data. This enables rapid customization of the network and provides a mechanism to adapt the network to a changing environment. In this paper, we describe the implementation of a prototype Active Network which is implemented in Java. We also illustrate the use of Active Networks to provide enhanced services at both the network and application levels.

Over the past few years, network management has steadily evolved from a centralized model, where all the management processing takes place on a single network management station, to distributed models, where management is distributed over a number, potentially large, of nodes. Among distributed models, one, the weakly distributed hierarchical model, has been around for several years, whereas a flurry of new ones, based on mobile code, distributed objects or cooperative agents, have only recently emerged. Which of these techniques will eventually win ? Will several ones have to coexist ? How do they compare to each other ? In order to provide a framework to analyze these issues, this paper presents a comprehensive typology of all network management paradigms known to date, whether they have been successfully implemented already or whether they are still confined to the research community. By comparing these models with those used in another research field, enterprise management, we delineate a common trend of evolution, and attempt to predict what the future holds for network management.

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 desire for flexible networking services has given rise to the concept of "active networks." Active networks provide a general framework for designing and implementing network-embedded services, typically by means of a programmable network infrastructure. A programmable network infrastructure creates significant new challenges for securing the network infrastructure. This paper

Recent research in ATM management has delegated control functions from the ATM switch into higher level open control architectures [1], [2], [3]. For example, functions such as Call Admission Control are implemented within such a control architecture rather than as an integral part of the switch. The association between the switch fabric and the switch control functions is made less strict, allowing, for example, a single entity to perform routing for a group of switches. This greater flexibility in the provision of control is accompanied by an increase in complexity resulting from the possibility of making control decisions remotely from the controlled network element. The location of the controller in relation to the fabric is not just an implementation issue; it has a large impact on the way we handle traditional Operation and Maintenance (OAM) functions. For example, recovering from partial failure of the network is problematic when the controlling entity is communicating with the...

Dynamically evolving a widely distributed service or application is a challenging systems design task. In this paper, we describe a plausible, high-level design for a common software framework that supports such extensible distributed services. Our design requires that the distributed service be implemented in an interpreted language, but our framework allows transparent and on-demand procedure instantiation at agents of the distributed service. In addition, this framework enables distributed services to be composed from reusable modules, and service sessions to be initiated from a single site.

Proposals for programmable network infrastructures, such as active networks and open signaling, provide programmers with access to network resources and data structures. The motivation for providing these interfaces is accelerated introduction of new services, but exposure of the interfaces introduces many new security risks. The risks can be reduced or eliminated via appropriate restrictions on the exported interfaces. In this article we describe some of the security issues raised by active networks. We then describe our secure active network environment architecture. SANE was designed as a security infrastructure for active networks, and was implemented in the SwitchWare architecture. SANE restricts the actions loaded modules (including "capsules") can perform by restricting the resources that can be named; this is further extended to remote invocation by means of cryptographic credentials. SANE can be extended to support restricted control of quality of service in a programmable...