Multicast Latency Research Articles

A lightweight and distributed geographic multicast routing protocol for IoT applications

In many Internet of Things (IoT) applications, messages may need to be disseminated to some specific objects or nodes using multicast transmissions. In the literature, the multicast routing protocol can be divided into non-geographic-based and geographic-based. Since devices’ locations can be roughly derived by localization schemes or by GPS devices, geographic-based multicast routing protocols are preferred since they can induce less control packet overheads. However, we observe that existing geographic-based multicast routing schemes have the following two drawbacks. First, network nodes need a lot of computations to decide directions of sending multicast packets. Second, when a network has some holes or voids, the constructed multicast paths will be long, and in some cases, the paths may contain loops. In this work, we proposed a lightweight and distributed geographic multicast routing protocol to solve the above problems. Our scheme contains three phases. First, the first phase selects intermediate nodes to reach multicast destinations. Then, the second phase removes loops and trims routes constructed in the first phase. Finally, the last phase checks if the selected multicast links can further be merged. The simulation results indicate that the proposed scheme can effectively reduce transmission links and shorten path lengths in the constructed multicast paths. To demonstrate the proposed scheme can be applied to IoT applications, we also implement the designed scheme in ZigBee-compliant platforms. The experiment results show that the proposed scheme can also help to reduce multicast latency.

Efficient round‐robin multicast scheduling for input‐queued switches

The input-queued (IQ) switch architecture is favoured for designing multicast high-speed switches because of its scalability and low implementation complexity. However, using the first-in-first-out (FIFO) queueing discipline at each input of the switch may cause the head-of-line (HOL) blocking problem. Using a separate queue for each output port at an input to reduce the HOL blocking, that is, the virtual output queuing discipline, increases the implementation complexity, which limits the scalability. Given the increasing link speed and network capacity, a low-complexity yet efficient multicast scheduling algorithm is required for next generation high-speed networks. This study proposes the novel efficient round-robin multicast scheduling algorithm for IQ architectures and demonstrates how this algorithm can be implemented as a hardware solution, which alleviates the multicast HOL blocking issue by means of queue look-ahead. Simulation results demonstrate that this FIFO-based IQ multicast architecture is able to achieve significant improvements in terms of multicast latency requirements by searching through a small number of cells beyond the HOL cells in the input queues. Furthermore, hardware synthesis results show that the proposed algorithm can be very efficiently implemented in hardware to perform multicast scheduling at very high speeds with only modest resource requirements.

Analysis of tree‐based multicast routing in wireless sensor networks with varying network metrics

SUMMARYWireless ad hoc and sensor networks are emerging with advances in electronic device technology, wireless communications and mobile computing with flexible and adaptable features. Routing protocols act as an interface between the lower and higher layers of the network protocol stack. Depending on the size of target nodes, routing techniques are classified into unicast, multicast and broadcast protocols. In this article, we give analysis and performance evaluation of tree‐based multicast routing in wireless sensor networks with varying network metrics. Geographic multicast routing (GMR) and its variations are used extensively in sensor networks. Multicast routing protocols considered in the analytical model are GMR, distributed GMR, demand scalable GMR, hierarchical GMR, destination clustering GMR and sink‐initiated GMR. Simulations are given with comparative analysis based on varying network metrics such as multicast group size, number of sink nodes, average multicast latency, number of clusters, packet delivery ratio, energy cost ratio and link failure rate. Analytical results indicate that wireless sensor network multicast routing protocols operate on the node structure (such as hierarchical, clustered, distributed, dense and sparse networks) and application specific parameters. Simulations indicate that hierarchical GMR is used for generic multicast applications and that destination clustering GMR and demand scalable GMR are used for distributed multicast applications. Copyright © 2012 John Wiley & Sons, Ltd.

Support Efficient and Fault-Tolerant Multicast in Bufferless Network-on-Chip

In this paper, we propose three Deflection-Routing-based Multicast (DRM) schemes for a bufferless NoC. The DRM scheme without packets replication (DRM_noPR) sends multicast packet through a non-deterministic path. The DRM schemes with adaptive packets replication (DRM_PR_src and DRM_PR_all) replicate multicast packets at the source or intermediate node according to the destination position and the state of output ports to reduce the average multicast latency. We also provide fault-tolerant supporting in these schemes through a reinforcement-learning-based method to reconfigure the routing table to tolerate permanent faulty links in the network. Simulation results illustrate that the DRM_PR_all scheme achieves 41%, 43% and 37% less latency on average than that of the DRM_noPR scheme and 27%, 29% and 25% less latency on average than that of the DRM_PR_src scheme under three synthetic traffic patterns respectively. In addition, all three fault-tolerant DRM schemes achieve acceptable performance degradation at various link fault rates without any packet lost.

Enhanced first-in-first-out-based round-robin multicast scheduling algorithm for input-queued switches

This study focuses on the multicast scheduling for M×N input-queued switches. An enhanced first-in-first-out -based round-robin multicast scheduling algorithm is proposed with a function of searching deeper into queues to reduce the head-of-line (HOL) blocking problem and thereby the multicast latency. Fan-out information of each input cell composes a traffic matrix and the scheduler executes a round-robin algorithm on each column independently. Scheduling decisions result in a decision matrix for the scheduler to release multicast cells accordingly. A matrix operation called sync is carried out on the decision matrix to reduce the number of transmission for each cell. To reduce the HOL blocking problem, a complement matrix is constructed based on the traffic matrix and the decision matrix, and a process of searching deeper into the queues is carried out to find cells that can be sent to the idle outputs. Simulation results show that the proposed function of searching deeper into the queues can alleviate the HOL blocking and as a result reduce the multicast latency significantly. Under both balanced and unbalanced multicast traffic, the proposed algorithm is able to maintain a stable throughput.

Trade-Offs between Latency, Complexity, and Load Balancing with Multicast Algorithms

The increasing number of collective communication-based services with a mass interest and the parallel increasing demand for service quality are paving the way toward end-to-end QoS guarantees. Although many multicast algorithms in interconnection networks have been widely reported in the literature, most of them handle the multicast communication within limited performance metrics, i.e., either delay/latency or throughput. In contrast, this study investigates the multicast communication within a group of QoS constrains, namely latency, jitter, throughput, and additional traffic caused. In this paper, we present the Qualified Groups (QGs) as a novel path-based multicast algorithm for interconnection networks. To the best of our knowledge, the QG is the first multicast algorithm that considers the multicast latency at both the network and node levels across different traffic scenarios in interconnection networks. Our analysis shows that the proposed multicast algorithm exhibits superior performance characteristics over other well-known path-based multicast algorithms under different operating conditions. In addition, our results show that the QG can significantly improve the parallelism of the multicast communication.

Reducing Multicast Redundancy and Latency in Multi-Interface Multi-Channel Wireless Mesh Networks

In wireless mesh networks, each node can be equipped with multiple network interface cards tuned to different channels. In this paper, we study the problem of collision-free multicast in multi-interface multi-channel wireless mesh networks. The concept of interface redundancy is proposed as a new criterion for the multicast/broadcast redundancy in wireless mesh networks, and we prove that building a multicast/broadcast tree with the minimum interface redundancy is NP-hard. We also prove that the minimum-latency multicasting problem in multi-channel wireless mesh networks is NP-hard. We present two heuristic-based algorithms which jointly reduce the interface redundancy and the multicast latency. Since broadcast can be considered as a special case of multicast, an approximate algorithm for low-redundancy broadcast tree construction is also proposed, which has a constant approximation ratio. Finally, the simulation results prove the effectiveness of our approach.

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.

Multicast communication in wormhole-routed 2D torus networks with hamiltonian cycle model

In this paper, we propose an efficient multipath multicast routing algorithm in wormhole-routed 2D torus networks. We first introduce a hamiltonian cycle model for exploiting the feature of torus networks. Based on this model, we find a hamiltonian cycle in torus networks. Then, an efficient multipath multicast routing algorithm with hamiltonian cycle model (mulitpath-HCM) is presented. The proposed multipath multicast routing algorithm utilizes communication channels more uniformly in order to reduce the path length of the routing messages, making the multicasting more efficient. Simulation results show that the multicast latency of the proposed multipath-HCM routing algorithm is superior to that of fixed and dual-path routing algorithms.

Performance analyses of serial-mode multicasting scheme in optical packet switched networks

The serial-mode multicasting scheme (SM), which can achieve duplication, buffering, and serial export of optical multicast packets in Optical Packet Switched (OPS) networks, is experimentally studied in this paper. Based on the experimental results, several limitations of this scheme, such as the multicast latency and signal impairment, are discussed. In addition, its performance in OPS networks is investigated by computer simulations. From the simulation results, a conclusion can be drawn that compared with the parallel-mode multicasting scheme (PM) producing multiple simultaneous copies of the optical packets by an optical power splitter or other devices, the SM scheme can increase the multicast success ratio and reduce the multicast retransmission times at the costs of some signal impairments and some extra transmission latency.

Resource Allocation Using Multiple Edge-Sharing Multicast Trees

A typical multicast network consists of a single tree, in which only a few internal nodes contribute most resources and are involved in performing the multicast functionality. This leads to an uneven and inefficient utilization of network resources. The problem is more pronounced in mobile ad hoc networks (MANETs), where network resources are limited. One solution is to split the multicast content over a number of trees. This provides several paths for the multicast content and would involve more nodes in implementing multicast functionality. Although this approach improves network utilization, overall multicast latency increases. This paper presents a distributed algorithm to construct multiple edge-sharing trees (MESTs) for small group multicast. MESTs balance the resource allocation and delay constraints by choosing to overlap certain edges that have low weight. Simulation results show that MESTs can generate multicast networks that have low delays and fair resource utilization. MESTs are designed to work with any form of multicast in both wired and wireless networks.

Scheduling and performance analysis of multicast interconnects

Multicast is an important operation in various emerging computing/networking applications. In particular, many multicast applications require not only multicast capability but also predictable communication performance, such as guaranteed multicast latency and bandwidth, called quality-of-service (QoS). In this paper, we consider scheduling in multicast interconnects, which aims to minimize the multicast latency for a set of multicast requests. Unfortunately, such a problem has been proved to be NP-Complete, which means that it is unlikely to find a fast exact algorithm for the multicast scheduling problem. We then turn to propose a simple, fast greedy multicast scheduling algorithm and derive a lower bound and an upper bound on the performance of the algorithm. As can be seen, while a lower bound is fairly straightforward, the upper bound is much more difficult to obtain. By translating the multicast scheduling problem into a graph theory problem and employing a random graph approach, we are able to obtain a probabilistic upper bound on the performance of the multicast scheduling algorithm. Our analytical and simulation results show that the performance of the proposed multicast scheduling algorithm is quite close to the lower bound and is statistically guaranteed by the probabilistic upper bound.

Fast Handover Mechanism for Seamless Multicasting Services in Mobile IPv6 Wireless Networks

This paper proposes a fast handover mechanism to provide a seamless multicast service for Mobile IPv6 hosts. With the proposed Fast handover based on a Mobile IP-Multi casting (FMIP-M) protocol, the selection of a new multicast service method, service preparation, and initialization procedures are all performed during the fast handover period, thereby enabling a reliable and efficient multicast service. When mobile hosts move to other networks, they can encounter data loss, out-of-synch problems for multicast data, and multicast service exchange latency. Therefore, the proposed FMIP-M allows the new access router to select a suitable multicast service method according to the multicast service-related network conditions and supports a reliable multicast transmission by compensating for data losses from the previous access router. An analysis is conducted of the overheads associated with a fast multicast handover, including the signaling cost and multicast packet-forwarding cost, where the costs are formulated based on timing diagrams, and compared with a fast handover using Mobile IPv6. The performance analysis and numerical results confirm that the proposed FMIP-M provides a fast multicast handover and reliable service with a relatively small signaling cost and packet-delivery cost.

FIFO-Based Multicast Scheduling Algorithm for Virtual Output Queued Packet Switches

Many networking/computing applications require high speed switching for multicast traffic at the switch/router level to save network bandwidth. However, existing queuing-based packet switches and scheduling algorithms cannot perform well under multicast traffic. While the speedup requirement makes the output queued switch difficult to scale, the single input queued switch suffers from head of line (HOL) blocking, which severely limits the network throughput. An efficient yet simple buffering strategy to remove the HOL blocking is to use the virtual output queued (VOQ) switch structure, which has been shown to perform well under unicast traffic. However, the traditional VOQ switch is impractical for multicast traffic because a VOQ switch for multicast traffic has to maintain an exponential number of queues in each input port (i.e., 2/sup N/-1 queues for a switch with N output ports). In this paper, we give a novel queue structure for the input buffers of a multicast VOQ switch by separately storing the address information and data information of a packet so that an input port only needs to manage a linear number (N) of queues. In conjunction with the multicast VOQ switch, we present a first-in-first-out based multicast scheduling algorithm, FIFO multicast scheduling (FIFOMS), and conduct extensive simulations to compare FIFOMS with other popular scheduling algorithms. Our results fully demonstrate the superiority of FIFOMS in both multicast latency and queue space requirement.

An Efficient Tree-Based Multicasting Algorithm on Wormhole-Routed Star Graph Interconnection Networks Embedded with Hamiltonian Path

Multicasting is an important issue for numerous applications in parallel and distributed computing. In multicasting, the same message is delivered from a source node to an arbitrary number of destination nodes. The star graph interconnection network has been recognized as an attractive alternative to the popular hypercube network. In this paper, we propose an efficient and deadlock-free tree-based multi-cast routing scheme for wormhole-routed star graph networks with hamiltonian path. In our proposed routing scheme, the router is with the input-buffer-based asynchronous replication mechanism that requires extra hardware cost. Meanwhile, the router simultaneously sends incoming flits on more than one outgoing channel. We perform simulation experiments with the network latency and the network traffic. Experimental results show that the proposed scheme reduces multicast latency more efficiently than other schemes.

Scheduled shared-tree multicasting for Bluetooth networks

Bluetooth is a newly developed technology designed as low-power, short-range, low-cost radios fitted for wireless connectivity among mobile devices. This paper addresses multicast routing for Bluetooth scatternets. Multicast is the technique of delivering fountainhead data to multiple destinations, which is widely used on wireless applications such as military command transmittal, video conference, mobile commerce, mobile learning, etc. As far as I know, there is no literature discussing multicast routing for Bluetooth scatternets. This paper proposes a proactive, source-routing multicast algorithm based on a pre-constructed scheduled shared core tree on scatternets, called scheduled shared-tree multicast (SSTM) algorithm. Before applying the SSTM algorithm, one should construct a shared core-based tree with simple scatternet-wide time-slot scheduling so that packet transmission is not affected by masters' polling delay and bridges' switching delay to reduce the multicast latency.

Multipath-Based Multicasting Strategies for Wormhole-Routed Star Graph Interconnection Networks

The star graph interconnection network has been recognized as an attractive alternative to the popular hypercube network. In this paper, we present a multipath-based multicast routing model for wormholerouted star graph networks, propose two efficient multipath routing schemes, and contrast the performance of the proposed schemes with the performance of the scheme presented in our previous work. Both of the two proposed schemes have been proven to be deadlock-free. The first scheme, simple multipath routing, uses multiple independent paths for concurrent multicasting. The second scheme, two-phase multipath routing, includes two phases: source-to-relay and relay-to-destination. For each phase, multicasting is carried out using simple multipath routing. Experimental results show that, for short and medium messages with small message startup latencies, the proposed schemes reduce multicast latency more efficiently than other schemes.

Nonblocking k-fold multicast networks

Multicast communication involves transmitting information from a single source to multiple destinations and is a requirement in high-performance networks. Current trends in networking applications indicate an increasing demand in future networks for multicast capability. Many multicast applications require not only multicast capability, but also predictable communication performance such as guaranteed multicast latency and bandwidth. In this paper, we present a design for a nonblocking k-fold multicast network, in which any destination node can be involved in up to k simultaneous multicast connections in a nonblocking manner. We also develop an efficient routing algorithm for the network. As can be seen, a k-fold multicast network has significantly lower network cost than that of k copies of ordinary 1-fold multicast networks and is a cost effective choice for supporting arbitrary multicast communication.

A new locality-based IP multicasting scheme for mobile hosts

Internet protocol multicasting is a mechanism widely used in the Internet to disseminate information. Multicast delivery paths may need to be frequently restructured along with host migrations, at the expense of nontrivial overhead or multicast latency. This paper presents a scheme with short multicast latency, while retaining acceptable overhead in adapting the delivery paths to mobile host locations. We exploit the locality in host movements and keep active the networks that mobile hosts have most recently visited. As long as hosts migrate within these active networks, multicast delivery paths can remain unchanged upon host movements. Performance results show that, compared with the best known proposal, our scheme is promising.

An efficient implementation of tree-based multicast routing for distributed shared-memory multiprocessors

This paper presents an efficient routing and flow control mechanism to implement multidestination message passing in wormhole networks. The mechanism is a variation of tree-based multicast with pruning to recover from deadlocks and it is well suited for distributed shared-memory multiprocessors (DSMs) with hardware cache coherence. It does not require any preprocessing of multicast messages reducing notably the software overhead required to send a multicast message. Also, it allows messages to use any deadlock-free routing function. The new scheme has been evaluated by simulation using synthetic loads. It achieves multicast latency reductions of 30% on average. Also it was compared with other multicast mechanisms proving its benefits. Finally, it can be easily implemented in hardware with minimal changes to existing unicast wormhole routers.