Multicast Operation Research Articles

Photonic integrated multicast switch-based optical wireless data center network

Optical wireless data center networks (OW-DCNs), which employ optical wireless technology and optical wired switching technology, are gaining interest as they promise to eliminate cable complexity, as well as to create high bandwidth interconnections and a low-cost and power-efficient system. In particular, the incorporation of optical tunable transmitters (T-TXs) and passive optical beam steering technologies is a promising way to build an OW-DCN benefitting from the potential of fast optical switching speed, low switch control complexity, and easy reconfiguration. However, the practical deployment of such an OW-DCN remains a challenge as fast (nanosecond) T-TX is required for fast optical switching operation. Implementation of fast T-TX can be realized by an array of lasers and optical gates, which are combined with photonic integration technology to achieve a compact, stable, and efficient nanosecond T-TX. In this paper, we propose an OW-DCN based on arrayed waveguide grating routers and fast T-TXs that exploit photonic integrated circuit multicast switches (PIC-MCSs). This PIC-MCS chip not only offers nanosecond-scale fast optical switching but also plays an essential role in enabling multicast operation, T-TX sharing, and dynamic bandwidth allocation between the intra- and inter-cluster networks. A 4×2 PIC-MCS has been designed, fabricated, and characterized in this proposed OW-DCN system. Experimental results validate that the proposed OW-DCN supports lossless, nanosecond, and multicast switching operation. Moreover, the dynamic bandwidth allocation and optical packet switching capability have been experimentally demonstrated. Finally, system performance with this fabricated PIC-MCS chip in a 4×4 rack OW-DCN is experimentally validated for different transmission scenarios and modulation formats. Wavelength division multiplexing multicast transmission with 50 Gb/s non-return-to-zero on–off-keying signals has been verified with less than 1.5 dB power penalty. 58 Gb/s four-level pulse-amplitude modulation transmission has also shown operation below the forward error correction threshold of 3.84×10−3 for all the different transmission scenarios.

Intelli-GATS: Dynamic Selection of the Wi-Fi Multicast Transmission Policy Using Interpretable-AI

COVID-19 has changed the way we use networks, as multimedia content now represents an even more significant portion of the traffic due to the rise in remote education and telecommuting. In this context, in which Wi-Fi is the predominant radio access technology (RAT), multicast transmissions have become a way to reduce overhead in the network when many users access the same content. However, Wi-Fi lacks a versatile multicast transmission method for ensuring efficiency, scalability, and reliability. Although the IEEE 802.11aa amendment defines different multicast operation modes, these perform well only in particular situations and do not adapt to different channel conditions. Moreover, methods for dynamically adapting them to the situation do not exist. In view of these shortcomings, artificial intelligence (AI) and machine learning (ML) have emerged as solutions to automating network management. However, the most accurate models usually operate as black boxes, triggering mistrust among human experts. Accordingly, research efforts have moved towards using Interpretable-AI models that humans can easily track. Thus, this work presents an Interpretable-AI solution designed to dynamically select the best multicast operation mode to improve the scalability and efficiency of this kind of transmission. The evaluation shows that our approach outperforms the standard by up to 38%.

Nanosecond photonic integrated multicast switch for low-latency optical wireless data center networks

Optical wireless data center networks (OW-DCNs), featuring no cable complexity, low latency, and high throughput, are highly attractive for the next generation of DCNs, while photonic integration provides a compact, low-power, and low-cost solution. In this Letter, we propose a novel, to the best of our knowledge, OW-DCN architecture using photonic integrated multicast switches (PIC-MCSs) to realize fast optical switching and multicast operation between top-of-the-rack switches (ToRs). By properly turning on/off the transmission channels of a semiconductor optical amplifier (SOA)-based PIC-MCS, the optical signals are directed to different target ToRs via arrayed waveguide grating routers (AWGRs) and free-space links. A 4×2 PIC-MCS with lossless multicast operation has been designed and fabricated. An OW-DCN of 4×4 interconnected racks has been experimentally demonstrated with the chip and a 4×4 AWGR. The results confirm the performance of low-latency switching, dynamic bandwidth reallocation, and WDM multicast transmission. Error-free operation at 10 Gb/s OOK with a power penalty of less than 1 dB is achieved, showing a negligible impact of cross talk on the PIC-MCS.

Area and Energy Opimized QCA Based Shuffle-Exchange Network with Multicast and Broadcast Configuration

In any wide-range processing system, rapid interconnecting networks are employed between the processing modules and embedded systems. This study deals with the optimized design and implementation of Switching Element (SE) which operates in four modes, accepting two inputs and delivering two outputs. The Shuffle-Exchange Network (SEN) can be used as a single-stage as well as a multi-stage network. SEN is used as an interconnection architecture which is implemented with exclusive input-output paths with simple design. The SE acts as a building block to the Multi-stage Shuffle-Exchange Network (M-SEN) with facilities to perform unicast and multicast operation on the inputs. An 8x8 M-SEN model is also implemented, which works in three modes of communication, termed as "One-to-One", "One-to-Many" and "One-to-All" M-SEN configuration. All the QCA circuits have been implemented and simulated using CAD tool QCADesigner. The proposed QCA-based M-SEN design is better in terms of area occupied by 14.63%, average energy dissipation by 22.75% and cell count with a reduction of 84 cells when compared to reference M-SEN architecture. The optimization of the design in terms of cell count and area results in lesser energy dissipation and hence can be used in future-generation complex networks and communication systems.

A 1024-Port Optical Uni- and Multicast Packet Switch Fabric

Novel Data Center (DC) architectures based on resource disaggregation hold the potential to increase the resource utilization at a reduced energy and cost envelope, imposing, however, significant challenges in the underlying DC network infrastructure that has to provide high-radix and high-bandwidth connectivity, while maintaining sub-μs latency. At the same time, the explosive growth of AI applications has transformed the traffic profiles on the majority of DC workloads calling for support of advanced network functionalities, such as multicasting. In this direction, we scale-up the Hipoλaos optical packet switch architecture to a thousand-port layout, at the same time upgrading its functionality to allow latency-free intra-tray multicasting. The feasibility of a 10.24-Tb/s capacity switch fabric with a 10-Gb/s line rate in a 1024-port configuration, with four-packet buffering capacity is experimentally demonstrated, revealing error-free performance with <3.4-dB power penalty. Optical multicasting to up-to five nodes is also experimentally validated at 10 Gb/s, with a power penalty variation of less than 1 dB between the different output ports, while multicast operation across the whole required spectral range of a 1024-port switch is investigated, utilizing pairs of wavelengths with different channel spacing. Network-level analysis of the 1024-port Hipoλaos switch revealed sub-μs p90-latency and ∼85% throughput, for the unicast case, when utilizing a two-packet-buffer design. Finally, the simulation model was extended to support the Hipoλaos multicast friendly layout, revealing up to 4250% throughput improvement, as compared to the conventional layout, while maintaining sub-μs latency.

Multicasting in a High-Port Sub-$\mu$ sec Latency Hipo$\lambda$ aos Optical Packet Switch

We demonstrate a Hipoλaos optical packet switch (OPS) configuration that can support optical data multicasting in a sub-μsec 256-port layout. The proposed multicast OPS relies on the low-latency and high-port Hipoλaos OPS architecture, extending its capabilities from unito multicast operation through simple modifications at its egress wavelength-routing stage. It exploits the WDM cyclic properties of the arrayed waveguide grating router stage in conjunction with multi-wavelength conversion (WC) in semiconductor optical amplifier-Mach-Zehnder interferometer (SOA-MZI) toward scaling from a unito a multicast OPS design, with the level of multi-wavelength WC defining the multicast degree. Optical multicasting up to five nodes is experimentally demonstrated at 10 Gb/s, revealing error-free operation at 10 -9 with less than 2-dB power penalty compared with the unicast operation. The broadband operational characteristics of the multicast operation have been also investigated at 10 Gb/s, utilizing pairs of wavelengths with different channel spacing and validating the multicast credentials of the switch across all the necessary wavelength channels for a 256-port configuration. Finally, a mixed traffic scenario involving both unicast and multicast optical traffic is demonstrated at 10 Gb/s, revealing error-free performance for all cases, with a <;0.2 dB excess power penalty of multicasted packets over the unicast data.

Software-Defined Silicon-Photonics-Based Metro Node for Spatial and Wavelength Superchannel Switching

Due to the growing popularity of optical superchannels and software-defined networking, reconfigurable optical add-drop multiplexer (ROADM) architectures for superchannel switching have recently attracted significant attention. ROADMs based on micro-electro-mechanical system (MEMS) and liquid crystal-on-silicon (LCoS) technologies are predominantly used. Motivated by requirements for low power, high-speed, small area footprint, and compact switching solutions, we propose and demonstrate spatial and wavelength flexible superchannel switching using monolithically integrated silicon photonics (SiP) micro-ring resonators (MRRs). We demonstrate the MRRs’ capabilities and potential to be used as a fundamental building block in ROADMs. Unicast and multicast switching operation of an entire superchannel is demonstrated after transmission over 50 km of standard single mode fiber. The performance of each sub-channel from the 120 Gb∕s QPSK Nyquist superchannel is analyzed, and degradation in error vector magnitude performance was observed for outer sub-channels due to the 3 dB bandwidth of the MRRs, which is comparable with the superchannel bandwidth. However, all sub-channels for all switching cases (unicast, multicast, and bi-directional operation) exhibit performance far below the 7%FEClimit. The switching time of the SiPMRRchip is such that high-capacity superchannel interconnects between users can be set up and reconfigured on the microsecond time scale.

Dynamic Resource Allocation Framework for MooD (MBMS Operation On-Demand)

The demand for mobile video is increasing every year. To address the strain on long term evolution (LTE) networks 3GPP introduced multimedia broadcast multicast operation (MBMS). As of LTE release 12, support for MBMS operation on-demand (MooD) was also added (MooD enables dynamic resource configuration of multicast flows). While multicast algorithms assuage the demands on the network, quality-of-service performance metrics no longer are considered an accurate measure of a user’s satisfaction with the network; recent multimedia studies show that quality-of-experience (QoE) is more accurate. In order to maximize the QoE of all users in a LTE MooD system, we propose two resource allocation algorithms, both of which efficiently allocate resource blocks (RBs) based on both the demand for each live video stream and the channel conditions of the users within each group. We also compare our resource allocation algorithms against four other commonly used resource allocation algorithms. Both of our algorithms achieve a higher QoE and video quality, when compared to other commonly used resource allocation algorithms. Furthermore, our algorithms demonstrate efficient resource allocation regardless of whether or not the RBs are sufficient.

Performance analysis of hybrid WDM-OTDM optical multicast overlay system employing 120 Gbps polarization and subcarrier multiplexed unicast signal with 40 Gbps multicast signal

In this paper, we have propose and investigated the performance of hybrid WDM-OTDM optical multicast overlay system which employs 120Gbps unicast and 40Gbps multicast data operating over SMF+DCF and amplifier link in C-band. The polarization and subcarrier multiplexed modulation formats are used to obtain 120Gbps unicast data and DPSK (differential phase shift keying) modulation format for 40Gbps multicast data transmission. In multicast operation, DPSK data is superimposed on to multiplexed unicast data channels. The impact of extinction ratio, input power and transmission distance on the performance of proposed system in terms of output optical power, BER and Q-factor has been investigated for both unicast and multicast data. We have also concluded that polarization and subcarrier multiplexed modulation formats are promising option to increase per channel capacity and less vulnerable to CD and PMD. In addition, the proposed system using hybrid modulation techniques offers higher bandwidth utilization efficiency at higher per channel data rate than conventional modulation formats.

Self-Organized Hash Based Secure Multicast Routing Over Ad Hoc Networks

Multicast group communication over mobile ad hoc networks has various challenges related to secure data transmission. In order to achieve this goal, there is a need to authenticate the group member as well as it is essential to protect the application data, routing information, and other network resources etc. Multicast-AODV (MAODV) is the extension of an AODV protocol, and there are several issues related to each multicast network operation. In the case of dynamic group behavior, it becomes more challenging to protect the resources of a particular group. Researchers have developed different solutions to secure multicast group communication, and their proposed solutions can be used for resource protection at different layers i.e. application layer, physical layer, network layer, etc. Each security solution can guard against a particular security threat. This research paper introduced a self-organized hash based secure routing scheme for multicast ad hoc networks. It uses group Diffie-Hellman method for key distribution. Route authentication and integrity, both are ensured by generating local flag codes and global hash values. In the case of any violation, route log is monitored to identify the malicious activities.

BTL - An Efficient Deadlock-Free Multicast Wormhole Algorithm to Optimize Traffic in 2D Torus Multicomputers

Multicast communication, in which the same message is sending from a source node to a set of destination nodes, is being increasingly demanded in multicomputer systems. It can be used to support several other collective communication operations. 2D torus network has many features. So, it has become increasingly important to multicomputer design. This paper presents an efficient multicast wormhole deadlock-free algorithm that Balance Traffic Load on 2D torus network; hence the name BTL algorithm. BTL algorithm handles multicast operation with a fixed number of message-passing steps irrespective of the network size. Also, it is designed such that can send messages to any number of destinations within two communication phases. Results from extensive comparative analysis show that BTL algorithm exhibit superior performance advantages over a well-known algorithm. General Terms Network, Multicomputer, and Algorithms.

Performance Evaluation of Multicast Overlay Routing Protocols

Abstract For almost three decades the multicast communication has been a subject of a dynamic research. It came to the world of the packet switching networks rather late and still has not become a fist class citizen of the Internet, yet the demand for such services is growing and thus the relevant technologies evolve persistently providing increasing quality and availability of the means of the group communication. The overlay approach to the multicast is an application layer realization which came to life due to certain deficiencies at the lower layers. In general the gain from using multicast for group communication instead of duplicated unicast links is that we avoid sending the same data many times through a single link. Such gain may be achieved wit the use of the router level mulitcast solution. The overlay solutions tend to approach his level of efficiency with a different degree of success. Therefore one of the main characteristics that is interesting when evaluating a particular overlay protocol is how well does it achieve the aforementioned gain. There are several metrics that allow for objective comparison of protocols in this regard. However this is not the only point of view to provide a valuable evaluation of the multicast overlay solutions. One of the important aspects of the modern group communication such as the IPTV or teleconferencing is the dynamic nature of the users’ participation. A particular group may be joined and left by multiple users at a very frequent rate which is critical to the resources management as well as to maintaining the integrity of the abstract communication structure, e.g. a tree spanning all the participants. In such case two major classes of the evaluation criteria emerge: the statical and the dynamical ones. They’re both very important and interdependent, however the means to measure them may differ significantly. In this article a wide variety of the multicast overlay protocols have been analysed and two of them have been chosen to be compared. The stress of the evaluation has been put on the dynamic aspects of the multicast overlay protocols operation.

Fuzzy-controlled Power-aware Multicast Routing (FPMR) for Mobile Ad Hoc Networks

Ad hoc networks are highly dynamic networks where the nodes are battery-powered. Routing in such networks is an issue of upcoming concern due to the possibility of frequent link breakage as a result of node mobility and/or high rate of energy depletion of nodes. Also to fulfill certain quality parameters, presence of multiple node disjoint paths become essential. Such paths aid in the optimal traffic distribution and reliability in case of path breakages. In this paper we propose a fuzzy controlled power aware multicast routing (FPMR) protocol that takes into account estimated network evolution in terms of residual energy of nodes w.r.t. approximated energy required to complete the multicast operation, link stability, geographical positions of multicast receivers etc. Extensive simulation experiments have been conducted to compare the performance of FPMR with other state-of-the –art multicast protocols. The results w.r.t. a wide range of parameters show that FPMR attains significantly high packet delivery ratio at much lesser cost than its competitors, thereby improving the lifetime of nodes.

ODMT: On-demand Inter-domain Multicast Tunneling

The tussle in IP multicast, where different enablers have interests that are adverse to each other, has led to a halt in inter-provider multicast deployment and created a situation in which enabling inter-domain multicast routing is considered a deterrent for network providers. This paper presents ODMT (On-demand Inter-domain Multicast Tun- neling), an on-demand inter-provider multicast tunneling that is autonomous in operation and manageable through its definable policy control. In the architectural design, we propose a new approach of enabling inter-provider multicast by decoupling the control-plane and forwarding-plane. Focusing on the control-plane without changing the forwarding- plane, our solution changes the traditional open multicast service model into a more manageable service model in inter-domain multicast operation, hence it eases the Internet-wide multicast deployment.

Performance evaluation for single‐ and semi‐layer multistage interconnection networks servicing multicast traffic by full multicast operation

AbstractHere a novel analytical method for performance prediction estimation of single‐ and multi‐layer multistage interconnection networks (MINs) under multicast environments is presented. The ‘Cell Replication While Routing’ is used as a packet routing technique and the ‘full multicast’ mode as transmission policy is employed in all the MINs under study. This model is developed for single‐layer MINs and is extended and applied to special types of multi‐layer MINs, called semi‐layer MINs, which support mixed traffic patterns such as unicast and multicast in uniform traffic conditions. The results confirm the significant performance saturation of single‐layer MINs and the improvement of corresponding performance indicators by semi‐layer MINs. The proposed analytical framework is anticipated to be a very useful tool in evaluating the performance of semi‐layer MINs in designing more efficient QoS networks. Copyright © 2010 John Wiley &amp; Sons, Ltd.

A hardware supported multicast scheme based on XY routing for 2-D mesh InfiniBand networks

The multicast operation is a useful operation in parallel applications. It is therefore important to ensure that for a given architecture, the parallel application runs efficiently. With the hardware-supported multicast of the InfiniBand Architecture (IBA), we propose a multicast scheme for m×n mesh InfiniBand networks based on XY routing. The basic concept of the proposed multicast scheme is to find the union sets of the output ports of switches, which are in the paths between the source node and each destination node in a multicast group. Furthermore, in the proposed scheme, we consider the usage of virtual lanes and evaluate their performance. We implement the proposed multicast scheme on a 2-D mesh InfiniBand network simulator. Several multicast configurations consisting of different message size, different traffic workload and different number of virtual lanes are simulated. The simulation results show that the proposed multicast scheme outperforms its corresponding unicast scheme for all simulation cases. The larger the message size, the larger the number of multicast source nodes, and the larger the size of the multicast group, the better the speedup that can be expected from the proposed multicast scheme. The usage of virtual lanes is also shown to improve the speed of the multicast operations.

Analytical model for performance evaluation of Multilayer Multistage Interconnection Networks servicing unicast and multicast traffic by partial multicast operation

Nowadays, since the proportion of multicast traffic has increased compared to that of unicast traffic, the need for Multilayer Multistage Interconnection Layers Networks (MLNINs) has become more intense. In this paper a thorough evaluation of the performance of MLMINs using an analytical model is presented, as such an evaluation has not previously been developed. The multicasting policy that is used by MLMIN queues is the “partial multicast” and all the MLMINs studied use the “Cell Replication While Routing” (CRWR) technique. The performance model was applied under different offered loads to various network size MLMINs supporting various proportions of unicast and multicast traffic. The results have been confirmed in some marginal cases by existing work and the study reveals quantitatively the improvement in the performance metrics of MLMINs compared to the corresponding single-layer MINs. The findings of this paper are important as they could be useful in building optimum networks regarding their performance.

Implementation of coarse wavelength division multiplexing multi-wavelength routing switch core for storage area networks

With an increasing demand on storage devices in network enterprises, storage area networks (SANs) have attracted significant attention and are currently considered as one of the most important network elements in the next generation optical Internet. An optical switch fabric capable of multicast transmission and multiple wavelength operation corresponding to a SAN's growth is critical, since SANs will soon suffer from data bottlenecks and cost inflation because of limited switching capabilities within pure electronics. The authors present and demonstrate a reconfigurable shutter-based free-space optical switching core capable of multicast transmission using multiple wavelengths per-fibre for use in optical SANs. The switch architecture, operation mechanism and the design of key components are described. New optical materials are utilised to raise the switching speed, and ferroelectric liquid crystals (FLCs) or transparent lanthanum-modified lead zirconate titanate (PLZT) have been compared. The optical performance of an implemented crossbar switch prototype is evaluated through a proposed node architecture constructed with a transceiver-based test-bed.

Communication modeling of multicast in all-port wormhole-routed NoCs

Multicast is one of the most frequently used collective communication operations in multi-core SoC platforms. Bus as the traditional interconnect architecture for SoC development has been highly efficient in delivering multicast messages. Since the bus is non-scalable, it can not address the bandwidth requirements of the large SoCs. The networks on-chip (NoCs) emerged as a scalable alternative to address the increasing communication demands of such systems. However, due to its hop-to-hop communication, the NoCs may not be able to deliver multicast operations as efficiently as buses do. Adopting multi-port routers has been an approach to improve the performance of the multicast operations in interconnection networks. This paper presents a novel analytical model to compute communication latency of the multicast operation in wormhole-routed interconnection networks employing asynchronous multi-port routers scheme. The model is applied to the Quarc NoC and its validity is verified by comparing the model predictions against the results obtained from a discrete-event simulator developed using OMNET++.

Experimental demonstration of layer-1 multicast for WDM networks using reconfigurable OADM

The feasibility of multicast-capable-reconfigurable optical add/drop multiplexer (MC-ROADM) based on broadcast-and-select switch is experimentally demonstrated. The MC-ROADM can support unicast connection as well as multicast connection, and can provide directionless switching and low insertion loss in path-through channel. We implement fully-reconfigurable multi-degree MC-ROADM based on wavelength selective switch, and evaluate multicasting performances by fully loading 40 × 10 Gbit/s wavelength division multiplexed (WDM) signals. For unicast and multicast operation, measured spectrum and bit-error-rate (BER) show good uniformity and no power penalty. After 1040 km transmission with 25 dB span loss, the measured BER is higher than forward-error-correction (FEC) limit for BER of 10 −15.