SoMR: A scalable distributed QoS multicast routing protocol

Many Internet multicast applications such as teleconferencing and remote diagnosis have Quality-of-Service (QoS) requirements. The requirements can be additive (end-to-end delay), multiplicative (loss rate), or of a bottleneck nature (bandwidth). Given such diverse requirements, it is a challenging task to build QoS-constrained multicast trees in a large network where no global network state is available. This paper proposes a scalable QoS multicast routing protocol (SoMR) that supports all three QoS requirement types. SoMR is scalable due to small communication overhead. It achieves favorable tradeoff between routing performance and routing overhead by carefully selecting the network sub-graph in which it searches for a path that can support the QoS requirements. The scope of search is automatically tuned based on the current network conditions. An early-warning mechanism helps detect and route around the long-delay paths in the network. The operations of SoMR are completely decentralized. They rely only on the local state stored at each router.     

移动分组无线网多播协议的设计与实现

提出了用于移动分组无线网的多播路由协议。在移动分组无线网环境中，多播路由协议起着非常重要的作用。传统的应用于有线网络的多播方法无法适应移动分组无线网具有的拓扑结构变化和带宽有限等特点。在协议中不需要维护全局的路由信息，而采用按需路由发现策略，动态建立路由信息及维持多播组成员关系。仿真实验显示协议在带宽较低、多播组成员数量变化较大的移动分组无线网环境中，具有较好的可靠性和工作效率。     

An Efficient and Secure Self-Healing Scheme for LKH

With the growing interest in converging fixed and mobile networks (FMC), mobile applications will require more and more resources from both the network and the mobile device. In such context, multicasting is essential because it lowers bandwidth consumption by simultaneously reaching a group of multiple recipients. Securing multicast flows has been extensively studied in the past, but none of the existing solutions were meant to handle the constraints imposed by mobile scenarios, in particular the high packet-loss rate. The need for a low overhead self-healing rekeying mechanism that is scalable, reliable and suitable for mobile environments has never been more urgent than with the arrival of FMC in 4G networks. This paper presents two self-healing recovery schemes based on the dual directional hash chains (DDHC) for the logical key hierarchy (LKH) rekeying protocol. This enables a member that has missed up to m consecutive key updates to recover the missing decryption keys without asking the group controller key server (GCKS) for retransmission. Conducted simulations show considerable improvements in the ratio of decrypted messages and in the rekey message overhead in high packet loss environments.     

Advanced multicast class-based bandwidth over-provisioning

Dynamic bandwidth aggregate over-provisioning has been proposed to provide differentiated services with scalable Quality of Service (QoS) control. Previous research showed that efficient over-reservation control allows minimizing QoS control overhead with reduced waste of bandwidth and blocking probability. However, existing over-reservation centric solutions are still inefficient in the face of network dynamics, as they are not able to accommodate the dynamic service demands, thus failing to optimize the bandwidth usage. This paper proposes a new Advanced Class-based resource Over-Reservation (ACOR) solution for multicast sessions, which seeks increased network resources utilization while minimizing QoS control overhead. More specifically, ACOR is able to dynamically update the share of bandwidth between different classes of service, providing improved results with less complexity than current solutions. Our analytical and simulation results prove the cost-effective and scalable QoS control capabilities of ACOR in decentralized networks with multiple distributed ingress routers coordinating the QoS control.     

Mesh-Mon: A multi-radio mesh monitoring and management system

Mesh networks are a potential solution for providing communication infrastructure in an emergency. They can be rapidly deployed by first responders in the wake of a major disaster to augment an existing wireless or wired network. We imagine a mesh node with multiple radios embedded in each emergency vehicle arriving at the site to form the backbone of a mobile wireless mesh. The ability of such a mesh network to monitor itself, diagnose faults and anticipate problems are essential features for its sustainable operation. Typical SNMP-based centralized solutions introduce a single point of failure and are unsuitable for managing such a network. Mesh-Mon is a decentralized monitoring and management system designed for such a mobile, rapidly deployed, unplanned mesh network and works independently of the underlying mesh routing protocol. Mesh-Mon nodes are designed to actively cooperate and use localized algorithms to predict, detect, diagnose and resolve network problems in a scalable manner. Mesh-Mon is independent of the underlying routing protocol and can operate even if the mesh routing protocol completely fails. One novel aspect of our approach is that we employ mobile users of the mesh, running software called Mesh-Mon-Ami, to ferry management packets between physically-disconnected partitions in a delay-tolerant-network manner. The main contributions of this paper are the design, implementation and evaluation of a comprehensive monitoring and management architecture that helps a network administrator proactively identify, diagnose and resolve a range of issues that can occur in a dynamic mesh network. In experiments on Dart-Mesh, our 16-node indoor mesh testbed, we found Mesh-Mon to be effective in quickly diagnosing and resolving a variety of problems with high accuracy, without adding significant management overhead.     

移动Ad Hoc网络中一种多播路由协议算法实现

MANET是一个多跳,节点无中心、自组织、互相通信而不依赖于预先架设的固定基础设施无线移动网络。本文提出了采用按需路由发现策略的移动Ad Hoc多播路由算法。此算法不需要维护全局的路由信息,通过按需路由发现过程,动态更新路由信息和建立多播转发组。多播数据包在转发组成员间进行有限泛洪,能够降低带宽的占用及减少路由更新信息的传播。仿真实验显示多播算法在带宽较低、多播组成员数量变化较大的移动分组无线网环境中,具有较好的可靠性和工作效率。     

A Scalable Overlay Multicast Architecture for Large-Scale Applications

In this paper, we propose a two-tier overlay multicast architecture (TOMA) to provide scalable and efficient multicast support for various group communication applications. In TOMA, multicast service overlay network (MSON) is advocated as the backbone service domain, while end users in access domains form a number of small clusters, in which an application-layer multicast protocol is used for the communication between the clustered end users. TOMA is able to provide efficient resource utilization with less control overhead, especially for large-scale applications. It also alleviates the state scalability problem and simplifies multicast tree construction and maintenance when there are large numbers of groups in the network. To help MSON providers efficiently plan backbone service overlay, we suggest several provisioning algorithms to locate proxies, select overlay links, and allocate link bandwidth. Extensive simulation studies demonstrate the promising performance of TOMA     

Design of a Scalable Multicast Scheme With an Application-Network Cross-Layer Approach

This paper develops an efficient and scalable multicast scheme for high-quality multimedia distribution. The traditional IP multicast, a pure network-layer solution, is bandwidth efficient in data delivery but not scalable in managing the multicast tree. The more recent overlay multicast establishes the data-dissemination structure at the application layer; however, it induces redundant traffic at the network layer. We propose an application-oriented multicast (AOM) protocol, which exploits the application-network cross-layer design. With AOM, each packet carries explicit destinations information, instead of an implicit group address, to facilitate the multicast data delivery; each router leverages the unicast IP routing table to determine necessary multicast copies and next-hop interfaces. In our design, all the multicast membership and addressing information traversing the network is encoded with bloom filters for low storage and bandwidth overhead. We theoretically prove that the AOM service model is loop-free and incurs no redundant traffic. The false positive performance of the bloom filter implementation is also analyzed. Moreover, we show that the AOM protocol is a generic design, applicable for both intra-domain and inter-domain scenarios with either symmetric or asymmetric routing.     

A fast and scalable technique for constructing multicast routing trees with optimized quality of service using a firefly based genetic algorithm

We are seeing an explosive proliferation of multimedia content made available on the Internet. Multimedia applications have a multipartite nature where content has to be disseminated to multiple parties using group communication. Overheads involved in distributing the content through unicast can be overcome by using multicast mode of transmission. Many multimedia applications such as audio-video news streams, stock quotes, live conferences and online gaming require strict Quality-of-service (QoS) guarantees. Optimizing a multicast tree for multiple QoS constraints is a multi-objective NP-hard optimization problem. In this work we propose an optimization that uses modified Genetic Algorithm (GA), a branch of evolutionary computation, to determine near-optimal multicast trees to satisfy multiple QoS constraints such as bandwidth, delay and packet loss. Our modification uses the Firefly effect to reduce the convergence time as well the premature convergence of the GA. Our simulation results show that our proposed algorithm is capable of finding a set of near-optimal multicast trees in computationally feasible time within a few iterations and is much faster than other optimization techniques proposed in research literature. Moreover we show that the protocol is scalable and exhibits a linear increase in processing overhead with the increase in group size.     

A Multicast Protocol Utilizing On-demand Routing Strategy for MPRN

This paper proposes a multicast protocol utilizing ondemand routing strategy for mobile packet radio network. It does not maintain permanent route tables with full topological views. Instead, multicast senders apply on-demand procedures to dynamically discover routes and build forwarding group in this protocol. The data packets are propagated by each forwarding group member via scoped flooding, so the protocol can reduce network bandwidth overhead and avoid the propagation of potentially large routing updates throughout the network.     

Scalable solutions for secure group communications

With the advent of digital technologies and widening Internet bandwidth in recent years there has been a marked rise in new multimedia services, including teleconferencing, pay-per-view TV, interactive simulations, software updates and real-time delivery of stock market information. Multicast data distribution has been used in controlled environments to deliver such services. However, the lack of secure, accountable multicast data distribution has prevented its use in general Internet environments. Proposals for multicast security solutions so far are complex and often require trust in intermediate components or are inefficient. A secure multicast protocol suite must provide data confidentiality and multicast packet source authentication. In this paper we present a robust, simple and efficient multicast key management protocol based on proxy encryption and a multicast data source authentication mechanism based on symmetric message authentication codes. The solutions are analyzed and compared to previously published schemes. The results show that the proposed schemes are efficient and scalable relative to existing schemes.     

Bandwidth guaranteed multicast scheduling for virtual output queued packet switches

Multicast enables efficient data transmission from one source to multiple destinations, and has been playing an important role in Internet multimedia applications. Although several multicast scheduling schemes for packet switches have been proposed in the literature, they usually aim to achieve only short multicast latency and high throughput without considering bandwidth guarantees. However, fair bandwidth allocation is critical for the quality of service (QoS) of the network, and is necessary to support multicast applications requiring guaranteed performance services, such as online audio and video streaming. This paper addresses the issue of bandwidth guaranteed multicast scheduling on virtual output queued (VOQ) switches. We propose the Credit based Multicast Fair scheduling (CMF) algorithm, which aims at achieving not only short multicast latency but also fair bandwidth allocation. CMF uses a credit based strategy to guarantee the reserved bandwidth of an input port on each output port of the switch. It keeps track of the difference between the reserved bandwidth and actually received bandwidth, and minimizes the difference to ensure fairness. Moreover, in order to fully utilize the multicast capability provided by the switch, CMF lets a multicast packet simultaneously send transmission requests to multiple output ports. In this way, a multicast packet has more chances to be delivered to multiple destination output ports in the same time slot and thus to achieve short multicast latency. Extensive simulations are conducted to evaluate the performance of CMF, and the results demonstrate that CMF achieves the two design goals: fair bandwidth allocation and short multicast latency.     

Performance evaluation of a mesh-evolving quality-of-service-aware multicast routing protocol for mobile ad hoc networks

The tremendous amount of multimedia applications running across the wireless communication medium makes quality of service (QoS) a fundamental requirement for mobile ad hoc networks. However, it is not easy to incorporate QoS into these networks. Moreover, the growing number of group-oriented applications also necessitates the efficient utilisation of network resources. The multicast model is a promising technique which can achieve this efficiency by facilitating the inherent broadcast capability of the wireless medium. The mesh-evolving ad hoc QoS multicast (MAQM) routing protocol is developed to address the resource efficiency and QoS problems with one, integrated solution. MAQM achieves multicast efficiency by tracking the availability of resources for each node within its neighbourhood. The QoS status is monitored continuously and announced periodically to the extent of QoS provision. Using these features, MAQM nodes can make their decisions on joining a new multicast session based on the sustainability of their perceived QoS. MAQM also evolves the initial multicast tree into a mesh during the course of an ongoing session to achieve a more robust network topology. Thus, MAQM integrates the concept of QoS-awareness into multicast routing in mobile ad hoc networks. Since ad hoc networks require the protocol control overhead to be as small as possible, we analyse the multicast session establishment process of MAQM to see its impact on the protocol performance in terms of system control overhead. We also evaluate the performance of MAQM through computer simulations using various qualitative and quantitative criteria. The simulation results validate our mathematical analysis of the control overhead and show that MAQM significantly improves multicast efficiency through its QoS-aware admission and routing decisions with an acceptably small overhead. Thus, MAQM shows that QoS is not only essential for, but also applicable to mobile ad hoc networks.     

Performance analysis of multicast algorithms for mobile satellite communication networks

With the rise of mobile computing and an increasing need for ubiquitous high-speed data connections, Internet-in-the-sky solutions are becoming increasingly viable. To reduce the network overhead of one-to-many transmissions, the multicast protocol has been devised. The implementation of multicast in these low earth orbit (LEO) constellations is a critical component to achieving an omnipresent network environment. This paper examines the system performance associated with two terrestrial-based multicast mobility solutions, distance vector multicast routing protocol (DVMRP) with mobile IP and on demand multicast routing protocol (ODMRP). These protocols are implemented and simulated in a satellite LEO constellation. Results from the simulation trials show the ODMRP protocol provided greater than 99% reliability in packet deliverability, at the cost of more than 8 bits of overhead for every 1 bit of data for multicast groups with multiple sources. In contrast, DVMRP proved robust and scalable, with data-to-overhead ratios increasing logarithmically with membership levels. DVMRP also had less than 70 ms of average end-to-end delay, providing stable transmissions at high loading and membership levels.     

一种基于广播和P2P技术的移动Ad Hoc网络文件传输协议

设计可靠高效的移动Ad Hoc网络文件传输协议具有广泛的应用价值。本文综合利用了基于共享树的广播技术与P2P文件传输技术,以可靠的数据重传机制取代复杂的拥塞控制机制,提出了一种新型的文件传输协议,并对协议时延与网络开销进行了性能分析。分析表明,此协议在文件较大、请求节点较多的情况下能很好地减少协议时延,有效地降低网络开销。     

Scalable datacenter multicast using in-packet bitmaps

Scalability is a key issue in datacenter multicast as it needs to support a large number of groups in commodity switches with limited fast memory. Previous in-packet Bloom filter-based datacenter multicast schemes have been proposed to address the scalability issue. They encode a multicast tree in a Bloom filter carried in each packet. However, these schemes induce high bandwidth overhead due to the false positives inherent in Bloom filters, and cannot scale well to the increasing variety of group sizes. In this paper, we propose an in-packet bitmap-based approach towards scalable datacenter multicast, improving the bandwidth efficiency. We use a bitmap to encode switch ports of a multicast tree in the packet header, eliminating false positive forwarding. In addition, we use a clustered Golomb coding method to compress in-packet bitmaps for further reducing the bandwidth overhead. Experimental results on simulations and a Click-based switch prototype demonstrate that our scheme achieves up to several orders of magnitude reductions in bandwidth overhead compared to previous schemes.     

A taxonomy of multicast protocols for Internet applications

The continuous growth in applications that require communications among a group of hosts or simultaneous dissemination of data to multiple sites on the Internet has led to considerable interest in multicast communication. These applications have different quality of service requirements such as deadlines to response time and tolerance to data loss. Internet multicast protocols provide a spectrum of services to cater for the needs of a wide array of multicast applications. The design alternatives of a multicast protocol for a particular application may lead to different performance characteristics, for example higher utilization of network bandwidth vs lower protocol processing requirements. Therefore a framework is required to various design choices available to design multicast protocols and evaluate the performance tradeoffs associated with these alternatives. Motivated by such a need and by the evolution of multicast applications over the Internet, this article presents a taxonomy of multicast protocols and a common framework to evaluate their performance.     

Multicast routing in mobile ad hoc networks by using a multiagent system

Multicast routing in mobile ad hoc networks (MANETs) poses several challenges due to inherent characteristics of the network such as node mobility, reliability, scarce resources, etc. This paper proposes an Agent Based Multicast Routing Scheme (ABMRS) in MANETs, which uses a set of static and mobile agents. Five types of agents are used in the scheme: Route manager static agent, Network initiation mobile agent, Network management static agent, Multicast initiation mobile agent and Multicast management static agent. The scheme operates in the following steps: (1) to identify reliable nodes; (2) to connect reliable nodes through intermediate nodes; (3) to construct a backbone for multicasting using reliable nodes and intermediate nodes; (4) to join multicast group members to the backbone; (5) to perform backbone and group members management in case of mobility. The scheme has been simulated in various network scenarios to test operation effectiveness in terms of performance parameters such as packet delivery ratio, control overheads and group reliability. Also, a comparison of proposed scheme with MAODV (Multicast Ad hoc on-demand Distance Vector) protocol is presented. ABMRS performs better than MAODV as observed from the simulation. ABMRS offers flexible and adaptable multicast services and also supports component based software development.     

一种基于MANET的多播协议的设计与实现

传统的应用于有线网络的多播方法很难适应MANET所具有的拓扑结构变化和带宽有限等特点，无法有效地应用于MANET。提出了采用按需路由发现策略的MANET多播路由协议MFGRP。在MFGRP协议中不需要维护全局的路由信息，通过按需路由发现过程，动态更新路由信息和建立网格。多播数据包在转发组成员间进行有限泛洪，使协议能够降低带宽的占用及减少路由更新信息的传播。模拟实验显示协议在带宽较低、多播组成员数量变化较大的移动分组无线网环境中，具有较好的可靠性和工作效率。