Active reliable multicast on CANEs: a case study

Local loss recovery for reliable multicast can provide significant performance improvement in terms of loss recovery latency, bandwidth consumption and network throughput. Active reliable multicast (ARM) is a novel loss recovery scheme for large-scale reliable multicast. When sufficient active resources of active routers (ARs) and associated cache are available, ARM gives good loss recovery latency performance. The authors build an analytical model for studying the optimal active resource allocation for ARM. They propose a top-down layering analysis (TDLA) approach to derive the expected loss recovery latency (ELRL). For a given multicast tree, the ELRL is derived as a function of the active resource allocation pattern. Simulation experiments reveal that high performance gains can be attained with limited active resources, which are properly allocated. It is also shown that simulation results have a good match with the analytical results. The analytical framework developed can be used for further investigation of various active resource allocation schemes and caching policies.

IP multicast plays a very important role in group communication. At the network level IP multicast provides an efficient one-to-many IP packets delivery but without providing any reliability guarantees. Desirable features of reliable multicast include low end-to-end delay, high throughput and scalability. Active networks open a new perspective in providing more efficient solutions to the problems of reliability. However, the existing active reliable multicast protocols are based on receiver-initiated approach for loss recovery. In this paper we propose a new active reliable multicast protocol by combining sender- initiated and receiver-initiated approaches for loss recovery. This approach helps to solve the scalability problems like acknowledgement implosion, recovery load balancing etc.

Security implications of implementing active network infrastructures using agent technology

We present MTCT, a congestion control scheme for large-scale reliable multicast. Congestion control for reliable multicast is important because of its wide applications in multimedia and collaborative computing, yet nontrivial, because of the potentially large number of receivers involved. Many schemes have been proposed to handle the recovery of lost packets in a scalable manner; but there is little work on the design and implementation of congestion control schemes for reliable multicast. We propose new techniques that can effectively handle instances of congestion occurring simultaneously at various parts of a multicast tree. Our protocol incorporates several novel features: (1) hierarchical congestion status reports that distribute the load of processing feedback from all receivers across the multicast group, (2) the relative time delay (RTD) concept which overcomes the difficulty of estimating round-trip times in tree-based multicast environments, (3) window-based control that prevents the sender from transmitting faster than packets leave the bottleneck link an the multicast path through which the sender's traffic flows, (4) a retransmission window that regulates the flow of repair packets to prevent local recovery from causing congestion, and (5) a selective acknowledgment scheme that prevents independent (i.e., non-congestion-related) packet loss from reducing the sender's transmission rate. We have implemented MTCP both on UDP in SunOS 5.6 and on the simulator ns, and we have conducted extensive Internet experiments and simulation to test the scalability and inter-fairness properties of the protocol. The encouraging results we have obtained support our confidence that TCP-like congestion control for large-scale reliable multicast is within our grasp.

Scalability is of paramount importance in the design of reliable multicast transport protocols, and requires careful consideration of a number of problems such as feedback implosion, retransmission scoping, distributed loss recovery, and congestion control. In this article, we present a reliable multicast architecture that invokes active services at strategic locations inside the network to comprehensively address these challenges. Active services provide the ability to quickly and efficiently recover from loss at the point of loss. They also exploit the physical hierarchy for feedback aggregation and effective retransmission scoping with minimal router support. We present two protocols, one for packet loss recovery and another for congestion control, and describe an experimental testbed where these have been implemented. Analytical and experimental results are used to demonstrate that the active services architecture improves resource usage, reduces latency for loss recovery, and provides TCP-friendly congestion control.

We present the router-assisted error control model (RRMEC), which takes advantage of the location and knowledge of the topology of routers to build a logical tree, and uses the repair host associated with the routers to buffer the data packet and perform retransmission recovery tasks. This model can establish a hierarchy being congruent with the multicast distribution tree and solve the major problem on reliable multicast efficiently. This paper gives the implementation of a prototype in active network, i.e., ANRM. The ANRM can provide an efficient method for rapid update and deployment of reliable multicast protocol.

Active networks are a promising way to develop new services for data transport, but active routers could also store "on the fly" streams of data for high level services such as Web cache and reliable multicast. In this paper we describe the merging of active networking with distributed storage solutions. We focus our approach on two dedicated frameworks : the IBP suite and the Tamanoir execution environment. We describe the overall architecture of the Active Logistical Storage suite and present first experimental results.

Active networks represent a new approach to network architecture. Routers can perform computations on user data, while packets can carry programs to be executed on routers and possibly change their state. Currently, the research community is divided concerning the usefulness of active networks. On the one hand, active networks provide a much more flexible network infrastructure, with increased capabilities. On the other hand, they are obviously more complex than traditional networks and raise considerable security issues. The purpose of this article is to provide a broad survey on active networks. The first goal is to highlight their efficiency in a variety of applications. After presenting some key points on each application, we discuss some current experimental technologies and assess the usefulness of active networks in congestion control, multicasting, caching, and network management. The second goal is to address the security issues that active networks raise: the problem is defined, and techniques for solving it are presented and elaborated upon with a description of a specific implementation of a secure environment and related performance measures. Issues related to the design of a programming language for active networks are also discussed. The third goal is to classify active network architectures based on their design approach. Thus an inclusive presentation of currently proposed architectures, which focuses on their design attributes, capabilities, performance, and security, is given.

A key component in the QoS architecture of the network is congestion control algorithms. Active congestion control is a new congestion control technology based on active network. it has small feedback delay, control nimble and high utility of network resource. A new active congestion control algorithm based on secondary routing was put forward, By the study of congestion detection, secondary routing search and choosing, multi-path distributary and control, a new congestion control method by packets redirection on active node was explored. The performance of this algorithm were validated by NS2, the following works of this algorithm was given out.

We have designed and built an active networking platform that adds active processing capabilities to the Click modular router (Kobler, E. et al., ACM Trans. on Computer Systems, 2000). The Clack platform comprises an active element for Click, a minimal set of libraries to provide interaction between protocols and end user applications, and a daemon process to handle active communications on end hosts. Many recent developments in active networking are restricted in that core router functions cannot be easily changed for experimentation or for adaptation to a particular situation. In the spirit of Click's fine grained modular approach, the Clack element is also divided into interchangeable components to allow, for example, the addition of new execution environments or protocol fetching rules. Our platform concurrently allows the use of multiple execution environments supported by the router's base operating system.

This paper presents the main concepts of the IST Project FAIN “Future Active IP Networks” [10], a three-year collaborative research project, whose main task is to develop and validate an open, flexible, programmable and dependable network architecture based on a novel active node approach. This generic architecture for active networks is an innovative integration of active networking, distributed object and mobile agent technology. Starting from the definition of a business model that underlines the FAIN architecture, we identify three key working areas for contribution: the active node platform layer, the service programming environment and a built-in management system. The active node platform layer of the FAIN Active Node is comprised of the kernel Operating System, a node resource access control framework, and active components for management, security and service provision. These elements provide the foundations for Execution Environments so that they can operate in an independent manner. A novel service programming environment is envisaged to enable the dynamic creation or update and to secure deployment and operation of protocols. Such an environment supports various role-specific ways of deployment, e.g. application-specific signalling or operator-governed network control signalling.KeywordsActive NetworkMobile AgentActive NodeExecution EnvironmentEnterprise ModelThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

This paper describes the design and implementation of a highly configurable and robust Mobile IP framework that employs active networking principles. Through the provision of open programmable interfaces and execution environment, new mobile services or application-specific customized services can be rapidly developed and deployed within the Mobile IP networking environment. ANTS [11] is being employed as the baseline active network execution environment for the implementation of our programmable Mobile IP framework. In particular, we have extended ANTS considerably to export mobile IP native interfaces to support mobile specific functionalities. The design of our active Mobile IP framework is currently implemented over the Linux operating system. The programmable framework is applied to the Mobile IP agent nodes namely, the mobile node, foreign agent, home agent and correspondent node. To demonstrate the ease of designing and deploying new mobile services, this paper describes the setup of an experiment to implement an active route optimization service.

This paper introduces a reliable multicast transport protocol RCCMP (reliable congestion controlled multicast protocol) that has been designed to be simple, scalable, reliable and TCP-friendly. The congestion control is a central part of the protocol, where the feedback of the worst receiver is used to control a transmission window in a TCP-like fashion. The scalability issue is addressed with an exponential timers scheme, that is also used to estimate the number of receivers involved in the communication. The protocol neither needs support from network elements nor maintains state information dependent of the number of receivers. The paper presents a number of simulation results on its performance. Besides, some design choices are evaluated.

New real-time applications frequently involve timing constraints related to accurate services from communication protocols. Concretely, real-time communication protocols utilize timers to implement these constraints between system event occurrences. In this context, the study of congestion control for Internet reliable multicast is at present an active research field related to real-time protocols. In this paper, the authors present an innovative real-time transport protocol named Scalable Reliable Multicast Stair Hybrid (SRMSH) as new hybrid multiple layer mechanism for multicast congestion control providing detection and recovery loss. This work is focused on formal specification of SRMSH approach using Communicating Real-Time State Machines as a formal method. Besides, SRMSH validation is presented within a formal proof framework in order to check the functional safety and liveness properties. As a result, authors outline a dynamical system framework in order to model behavior of their presented solution.

The study of congestion control for Internet reliable multicast is at present an active research field. In this paper we present scalable reliable multicast stair hybrid (SRMSH) as a multiple layer mechanism for multicast congestion control providing detection and recovery loss. We simulated SRMSH with different traffic sources to measure heterogeneity, scalability and fairness. Our work focus on bandwidth analysis and results clearly conclude that SRMSH exhibits reasonable throughput using these metrics and a good performance competing with typical traffic flow from Internet like TCP.