Overlay Multicast Network Research Articles

BDS+: An Inter-Datacenter Data Replication System With Dynamic Bandwidth Separation

Many important cloud services require replicating massive data from one datacenter (DC) to multiple DCs. While the performance of pair-wise inter-DC data transfers has been much improved, prior solutions are insufficient to optimize bulk-data multicast, as they fail to explore the rich inter-DC overlay paths that exist in geo-distributed DCs, as well as the remaining bandwidth reserved for online traffic under fixed bandwidth separation scheme. To take advantage of these opportunities, we present BDS+, a near-optimal network system for large-scale inter-DC data replication. BDS+ is an application-level multicast overlay network with a fully centralized architecture, allowing a central controller to maintain an up-to-date global view of data delivery status of intermediate servers, in order to fully utilize the available overlay paths. Furthermore, in each overlay path, it leverages dynamic bandwidth separation to make use of the remaining available bandwidth reserved for online traffic. By constantly estimating online traffic demand and rescheduling bulk-data transfers accordingly, BDS+ can further speed up the massive data multicast. Through a pilot deployment in one of the largest online service providers and large-scale real-trace simulations, we show that BDS+ can achieve 3- 5× speedup over the provider's existing system and several well-known overlay routing baselines of static bandwidth separation. Moreover, dynamic bandwidth separation can further reduce the completion time of bulk data transfers by 1.2 to 1.3 times.

Modeling and optimization of maximum flow survivable overlay multicast with predefined routing trees

Overlay networks employ underlying network technologies in order to provide end-system related communication and over the years overlays have been getting more and more attention in research community and in business world as well. Since overlays tackle many drawbacks present in pure “link-router-network” engineering, they have become an excellent solution for multimedia-oriented applications. A good example comprises multicast communications, where an overlay system, in contrast to IP Multicast, eliminates many issues related to scalability or management control. This paper focuses on modeling and optimization of overlay multicast networks aimed at realizing maximum throughput with survivability constraints, where survivability defines the ability of a multicast system to limit potential throughput losses in case of a failure of single virtual link. We present linear formulation derived from fractional tree packing problems based on predefined topologies which may route multicast traffic. Linear model might be used for obtaining optimal multicast structures, however its applicability is limited by increasing sizes of networks. Hence, we also design and evaluate heuristic searches dedicated to optimization of maximum flow survivable overlay multicast networks.

A Distributed Method for Constructing a P2P Overlay Multicast Network using Computational Intelligence

In this paper, we propose a method that can construct efficiently a P2P overlay multicast network composed of many heterogeneous peers in communication bandwidth, processing power and a storage size by selecting a peer in a distributed fashion using an ant-colony theory that is one of the computational intelligence methods. The proposed method considers not only the capacity of a peer but also the number of children peers supported by the peer and the hop distance between a multicast source and the peer when selecting a parent peer of a newly joining node. Thus, an P2P multicast overlay network is constructed efficiently in that the distances between a multicast source and peers are maintained small. In addition, the proposed method works in a distributed fashion in that peers use their local information to find a parent node. Thus, compared to a centralized method where a centralized server maintains and controls the overlay construction process, the proposed method scales well. Through simulations, we show that, by making a few high capacity peers support a lot of low capacity peers, the proposed method can maintain the size of overlay network small even there are a few thousands of peers in the network.

A Distributed Method for Constructing a P2P Overlay Multicast Network using Computational Intelligence

In this paper, we propose a method that can construct efficiently a P2P overlay multicast network composed of many heterogeneous peers in communication bandwidth, processing power and a storage size by selecting a peer in a distributed fashion using an ant-colony theory that is one of the computational intelligence methods. The proposed method considers not only the capacity of a peer but also the number of children peers supported by the peer and the hop distance between a multicast source and the peer when selecting a parent peer of a newly joining node. Thus, an P2P multicast overlay network is constructed efficiently in that the distances between a multicast source and peers are maintained small. In addition, the proposed method works in a distributed fashion in that peers use their local information to find a parent node. Thus, compared to a centralized method where a centralized server maintains and controls the overlay construction process, the proposed method scales well. Through simulations, we show that, by making a few high capacity peers support a lot of low capacity peers, the proposed method can maintain the size of overlay network small even there are a few thousands of peers in the network.

Scaling Group Communication Services with Self-adaptive and Utility-driven Message Routing

Group communication services typically generate large multicast data streams. Delivering such massive data streams to the end system nodes at the edge of the Internet has been a challenging problem in terms of high stress on the network links and high demand on network resources and routing node capacities. Most of existing research has been dedicated on geo-distance based routing with various optimizations to alleviate the performance impact on geo-distance based routing due to unpredictable network dynamics. Most representative techniques are targeted at reducing the delivery path length or optimizing routing path by utilizing network locality. In this paper, we identify the inefficiency of geo-distance based routing protocols in many existing multicast overlay networks in terms of both resource utilization and group communication efficiency. To address this issue, we develop a utility-based routing scheme (UDR) that can provide efficient group communication services in a decentralized geographical overlay network. Our approach makes three unique contributions. First, we introduce a utility function to refine the geo-distance based routing in such a way that the routing path selection can carefully incorporate both geo-distance based metric and the network latency. Second, we enhance our utility driven routing scheme with self-adaptive capability by considering the nodes' state and network density. Thus, nodes in the multicast network can dynamically accommodate the changes of network conditions based solely on their local knowledge about the network. Third, we devise a suite of optimization techniques to minimize the maintenance cost and computational complexity of our self-adaptive and utility-drive routing scheme. We evaluate our approach through extensive experiments based on a realistic network topology model and show that the UDR method is highly scalable and it effectively enhances the multicast delivery efficiency for large scale group communication services compared to existing geo-distance based routing protocols.

A Secure and Stable Multicast Overlay Network with Load Balancing for Scalable IPTV Services

The emerging multimedia Internet application IPTV over P2P network preserves significant advantages in scalability. IPTV media content delivered in P2P networks over public Internet still preserves the issues of privacy and intellectual property rights. In this paper, we use SIP protocol to construct a secure application-layer multicast overlay network for IPTV, called SIPTVMON. SIPTVMON can secure all the IPTV media delivery paths against eavesdroppers via elliptic-curve Diffie-Hellman (ECDH) key exchange on SIP signaling and AES encryption. Its load-balancing overlay tree is also optimized from peer heterogeneity and churn of peer joining and leaving to minimize both service degradation and latency. The performance results from large-scale simulations and experiments on different optimization criteria demonstrate SIPTVMON's cost effectiveness in quality of privacy protection, stability from user churn, and good perceptual quality of objective PSNR values for scalable IPTV services over Internet.

Strategic behavior modeling of multi-service overlay multicast networks based on auction mechanism design

Since the users of overlay multicast networks belong to different administrative domains, they are selfish in nature; resulting in degradation of performance. That is why strategic behavior modeling is a hot topic in the area of the overlay multicast networks. Mechanism design is the most versatile tool for strategic behavior modeling in microeconomics. In this paper, we model the strategic behavior of the selfish peers by leveraging the rich theory of mechanism design using the concept of economic auctions. By considering the bandwidth of services as the commodity, we design a revenue-maximizing auction mechanism. The sellers are either the origin servers or the peers who forward the digital multimedia content to their downstream peers. For each seller, the corresponding downstream peers play the role of buyers who are referred to as bidders. Each bidder submits a sealed bid to the corresponding seller. The highest bidder wins and pays its bid for the service. Also, we derive analytical closed-form expressions for upper bounds relevant to the performance metrics. The experimental validation proves the scalability and the efficiency of the proposed mechanism.

Towards strategic bandwidth sharing in overlay multicast networks based on mechanism design theory

Abstract The selfish behavior of the users in the overlay multicast networks can lead to degradation of the performance. In this paper, we target the mechanism design for the overlay networks based on the monopoly auction economies. In our proposed auction mechanism, the bandwidth of the service offered by the origin servers can be thought of as commodity. In this auction, the sellers are either the origin servers or the peers who forward the content to their downstream peers. Also, the corresponding downstream peers of each seller play the role of buyers who are referred to as bidders. Each bidder submits a sealed bid to its corresponding seller. The high bidder wins and pays its bid for the service. By theoretical and experimental analysis, we prove that the proposed auction mechanism achieves performance improvements in the overlay network.

Effective distributed service architecture for ubiquitous video surveillance

Video surveillance systems are playing an important role to protect lives and assets of individuals, enterprises and governments. Due to the prevalence of wired and wireless access to Internet, it would be a trend to integrate present isolated video surveillance systems by applying distributed computing environment and to further gestate diversified multimedia intelligent surveillance (MIS) applications in ubiquity. In this paper, we propose a distributed and secure architecture for ubiquitous video surveillance (UVS) services over Internet and error-prone wireless networks with scalability, ubiquity and privacy. As cloud computing, users consume UVS related resources as a service and do not need to own the physical infrastructure, platform, or software. To protect the service privacy, preserve the service scalability and provide reliable UVS video streaming for end users, we apply the AES security mechanism, multicast overlay network and forward error correction (FEC), respectively. Different value-added services can be created and added to this architecture without introducing much traffic load and degrading service quality. Besides, we construct an experimental test-bed for UVS system with three kinds of services to detect fire and fall-incident features and record the captured video at the same time. Experimental results showed that the proposed distributed service architecture is effective and numbers of services on different multicast islands were successfully connected without influencing the playback quality. The average sending rate and the receiving rates of these services are quite similar, and the surveillance video is smoothly played.

An efficient networking technique for synchronous e-learning platforms in corporate environments

A synchronous e-learning platform constitutes an effective tool to implement training programs for human resources in large corporations. These organizations are usually widely dispersed in multiple sites, so the delivery of multimedia data over the whole corporation during an e-learning activity is a true challenge. Multimedia data is usually delivered using the RTP protocol. Although an RTP session can involve multiple participants and has no restriction on the underlying network, it is usually restricted to IP multicast scopes. However, IP multicast is rarely available throughout corporate networks. In this paper, an efficient delivery technique based on an overlay multicast network is proposed. The overlay is made up of multiple servers that operate at the RTP level and combine unicast and native multicast transport whenever possible. This technique has proved to be more efficient than a technique based exclusively on unicast delivery.

Distributed max–min flow control for multi-rate overlay multicast

We present a distributed algorithm to compute bandwidth max-min fair rates in an overlay multicast network supporting multi-rate data delivery. The proposed algorithm is scalable in that it does not require each logical link to maintain the saturation status of all sessions and virtual sessions traveling through it, stable in that it converges asymptotically to the desired equilibrium satisfying the minimum plus max-min fairness even in the presence of heterogeneous round-trip delays, and has explicit link buffer control in that the buffer occupancy of every bottlenecked link in the network asymptotically converges to the pre-defined value. The algorithm is based on PI (proportional integral) control in the feedback control theory and by appealing to the Nyquist stability criterion, a usable stability condition is derived in the presence of sources with heterogeneous round-trip delays. In addition, we propose an efficient feedback consolidation algorithm which is computationally simpler than its hard-synchronization based counterpart and eliminates unnecessary consolidation delay by preventing it from awaiting backward control packets that do not directly contribute to the session rate. Through simulations we further verify the analytical results and the performance of the proposed multi-rate multicast flow control scheme based on these two algorithms.

A Self-organized Clustering-based Overlay Network for Application Level Multicast

Peer-to-Peer Overlay networks enabling an end-end application level-multicast service have drawn enormous attention. This paper proposes a self-organized -Multicast Overlay Network ( - MON) that enables an efficient end-end application level multicast. The -MON is organized into MON-Clusters, where δ is the maximum physical number of hops between any two end-nodes in each MON-Cluster. Thus, end-users accessing from different areas are able to broadcast data into each MON-Cluster within a constant δ physical number of hops. However in a dense-mode, increasing the size of MON-Clusters induces a long logical diameter that manifests high stress per physical links and high delay to disseminate data. Thus, this paper limits the expansion of each MON-Cluster within a specific logical diameter μ. Each MON-Cluster is constructed with at most μ logical hops over δ physical hops. Thus, end-users are able to efficiently disseminate data into each MON-Cluster within μ logical hops over δ physical hops with reasonable stress per physical links and bandwidth consumption.

A Framework for Mitigating Attacks Against Measurement-Based Adaptation Mechanisms in Unstructured Multicast Overlay Networks

Many multicast overlay networks maintain application-specific performance goals by dynamically adapting the overlay structure when the monitored performance becomes inadequate. This adaptation results in an unstructured overlay where no neighbor selection constraints are imposed. Although such networks provide resilience to benign failures, they are susceptible to attacks conducted by adversaries that compromise overlay nodes. Previous defense solutions proposed to address attacks against overlay networks rely on strong organizational constraints and are not effective for unstructured overlays. In this work, we identify, demonstrate and mitigate insider attacks against measurement-based adaptation mechanisms in unstructured multicast overlay networks. We propose techniques to decrease the number of incorrect adaptations by using outlier detection and limit the impact of malicious nodes by aggregating local information to derive global reputation for each node. We demonstrate the attacks and mitigation techniques through real-life deployments of a mature overlay multicast system.

GMAC: An overlay multicast network for mobile agent platforms

The lack of proper support for multicast services in the Internet has hindered the widespread use of applications that rely on group communication services such as mobile software agents. Although they do not require high bandwidth or heavy traffic, these types of applications need to cooperate in a scalable, fair and decentralized way. This paper presents GMAC, an overlay network that implements all multicast related functionality–including membership management and packet forwarding–in the end systems. GMAC introduces a new approach for providing multicast services for mobile agent platforms in a decentralized way, where group members cooperate in a fair way, minimize the protocol overhead, thus achieving great scalability. Simulations comparing GMAC with other approaches, in aspects such as end-to-end group propagation delay, group latency, group bandwidth, protocol overhead, resource utilization and failure recovery, show that GMAC is a scalable and robust solution to provide multicast services in a decentralized way to mobile software agent platforms with requirements similar to MoviLog.

Message Dropping Attacks in Overlay Networks

Overlay multicast networks are used by service providers to distribute contents such as Web pages, static and streaming multimedia data, or security updates to a large number of users. However, such networks are extremely vulnerable to message-dropping attacks by malicious or selfish nodes that intentionally drop the packets they are required to forward to others. It is difficult to detect such attacks both efficiently and effectively and to further identify the attackers, especially when members in the overlay switch between online/offline statuses frequently. In this article, we consider various attacking strategies of an attacker and propose an optimal sampling-based scheme to detect such attacks in the overlay network. We analyze the detection problem from a game-theoretical viewpoint and show that our scheme outperforms a random sampling-based scheme in terms of detection rate. In addition, based on a reputation system, we propose a sampling-based path-resolving scheme to identify compromised or selfish nodes. Unlike other existing approaches, our schemes do not assume global knowledge of the overlay hierarchy and work for dynamic overlay networks as well. Extensive analysis and simulation results show that besides being band width efficient, our schemes have high detection and identification rates and low false-positive rates.

Characterizing Overlay Multicast Networks and Their Costs

Overlay networks among cooperating hosts have recently emerged as a viable solution to several challenging problems, including multicasting, routing, content distribution, and peer-to-peer services. Application-level overlays, however, incur a performance penalty over router-level solutions. This paper quantifies and explains this performance penalty for overlay multicast trees via: 1) Internet experimental data; 2) simulations; and 3) theoretical models. We compare a number of overlay multicast protocols with respect to overlay tree structure, and underlying network characteristics. Experimental data and simulations illustrate that the mean number of hops and mean per-hop delay between parent and child hosts in overlay trees generally decrease as the level of the host in the overlay tree increases. Overlay multicast routing strategies, overlay host distribution, and Internet topology characteristics are identified as three primary causes of the observed phenomenon. We show that this phenomenon yields overlay tree cost savings: Our results reveal that the normalized cost L(n)/U(n) is propn <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.9</sup> for small n, where L(n) is the total number of hops in all overlay links, U(n) is the average number of hops on the source to receiver unicast paths, and n is the number of members in the overlay multicast session. This can be compared to an IP multicast cost proportional to n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.6</sup> to n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.8</sup>

Mobile Ad Hoc 네트워크를 위한 계층적 오버레이 멀티캐스트 구조 연구

오버레이 네트워크는 하부계층의 네트워크에 변화가 있어도 응용계층의 트리에는 변화를 줄 필요가 없으며, 오버레이 네트워크가 멀티캐스트를 지원하지 않는 노드들이 존재하는 환경에서도 만들어질 수 있게 해준다. 오버레이 프로토콜은 동적인 그룹을 모니터링하는 반면, 하부계층의 유니캐스트 프로토콜은 동적인 네트워크를 책임짐으로써, 동적인 환경에서도 제어 오버헤드를 줄이고, 프로토콜의 오퍼레이션을 안정적으로 만든다. 그러나, 만약 오버레이 멀티캐스트 프로토콜이 구성원의 위치정보를 모른다면, 효율적인 멀티캐스트 트리를 만드는 것은 매우 어렵다. 그래서, 위치정보를 이용한 계층적 오버레이 멀티캐스트 구조(HOMA: Hierarchical Overlay Multicast Architecture)를 본 논문에서 제안한다. 제안된 구조는 멀티캐스트에 참여하는 호스트들만으로 정적인 지역을 기반으로 동적 그룹을 만들어서 상위 계층에서는 그룹을 대표하는 호스트들 간의 오버레이 멀티캐스트 망을 형성하근 하위 계층에서는 지역에 속한 멀티캐스트 호스트들 간의 멀티캐스트를 지원하는 응용 계층의 2-계층 오버레이 멀티캐스트이다. 이것은 GPS를 사용하고, 지리적 영역을 활용하며 노드의 이동에 크게 영향을 받지 않는 지역 기반의 상위 계층의 오버레이 멀티캐스트 트리를 보여준다. 시뮬레이션 결과는 멀티캐스트의 효율성의 문제를 효과적으로 해결하였음을 보여준다. Overlay network eliminates the need to change the application-layer tree when the underlying network changes and enables the overlay network to survive in environments where nonmember nodes do not support multicast functionality. An overlay protocol monitors group dynamics, while underlying unicast protocols track network dynamics, resulting in more stable protocol operation and low control overhead even in a highly dynamic environment. But, if overlay multicast protocols does not know the location information of node, this makes it very difficult to build an efficient multicasting tree. So, we propose a Hierarchical Overlay Multicast Architecture (HOMA) with the location information. Because proposed architecture makes static region-based dynamic group by multicast members, it is 2-tired overlay multicasts of application layer that higher layer forms overlay multicast network between members that represent group, and support multicast between multicast members belonging to region at lower layer. This use GPS, take advantage of geographical region, and realizes a region-sensitive higher layer overlay multicast tree which is impervious to the movements of nodes. The simulation results show that our approach solves the efficiency problem effectively.

Explicit routing in multicast overlay networks

Application Level Multicast is a promising approach to overcome the deployment problems of IP level multicast by establishing delivery trees using overlay links among end systems. This paper presents algorithms to support traffic engineering, to improve the reliability of multicast delivery, and to facilitate secure group communications. First, we introduce the so-called backup multicast tree algorithm to compute a set of n − 1 backup multicast delivery trees from the default multicast tree. Each backup multicast tree has exactly one link of the default multicast tree that is replaced by a backup link from the set of available links. The algorithm can calculate this set of trees with a complexity of O ( m log n), which is identical with the complexity of well known minimum spanning tree algorithms. The so-called reduced multicast tree algorithm is based on the backup multicast tree algorithm and can calculate a tree from the default multicast tree by removing a particular node and by replacing the links of the removed node. Using the algorithms trees can be calculated individually by each of the nodes but it requires global topology knowledge. We therefore discuss distributed versions of the algorithms.

Reliable overlay multicast trees for private Internet broadcasting with multiple sessions

With rapid advances of computing technologies and high speed networks, various high volume multimedia services have become popular in the Internet. Private Internet broadcasting is a typical way to support these services and overlay multicast technology is known to be a promising solution to support this method. In an overlay multicast network, members are dynamically joining or leaving their multicast group. To reduce frequent updates of multicast members and provide a reliable multicast route, overlay multicast trees are investigated. The problem is formulated as a binary integer programming which maximizes the minimum link reliability for all multicast sessions. Tabu search heuristic is developed with repeated intensification and diversification. Robust computational result is obtained that is comparable to the optimal solution and applicable in real time.

Placement of proxy-based multicast overlays

Proxy-based multicast is an approach to implementing the multicast function with proxy servers, which has many advantages compared to the IP multicast. When proxy locations are predetermined, many routing algorithms can be used to build a multicast overlay network. On the other hand, the problem of where to place proxies has not been extensively studied yet. A study on the placement problem for proxy-based multicast is presented in this paper. The objectives of proxy placement can be minimization of delay time, minimization of bandwidth consumption, or minimization of both. These performance metrics are studied in this paper and a number of algorithms are proposed for multicast proxy placement. Performance study is presented and practical issues of proxy placement are also discussed.