This paper analyzes performance differences between interrupt-based and polling-based asynchronous I/O interfaces in high CPU contention scenarios. It examines how the choice of I/O Interface can differ depending on the performance of NVMe SSDs, particularly when using PCIe 3.0 and PCIe 4.0-based SSDs.

In this paper, we propose two schemes that improve the delay and the current consumption for efficient polling communications in multi-hop networks based on the receiver-initiated media access control (MAC) protocol. Polling communications can offer reliable data collection by avoiding communication collisions, but the larger delay and current consumption for the round-trip operation should be improved. The first proposal is an enhanced source routing scheme for downlink communications. In the proposed scheme, multiple candidates of relay terminals can be loaded in the routing information, so the route is not specified uniquely. The improvement of the delay and the current consumption is achieved by shortening the waiting time for communication timings based on the flexible routing. The second proposal is a round-trip delay reduction scheme which focuses on the bi-directionality of polling communications. The proposed scheme reduces the round-trip delay by offering frequent communication timings for uplink communications. Also, this paper proposes the joint application of the enhanced source routing scheme and the round-trip delay reduction scheme in polling communications. Computer simulations that suppose a multi-hop network based on the feathery receiver-initiated transmission (F-RIT) protocol in stable channel conditions are carried out. The results show the effectiveness of the proposed schemes in improving the delay and the current consumption. When the polling interval is 900s, the combination of the two proposed schemes improves the round-trip delay by up to 44.1% and the current consumption by up to 38.7% in average.

Energy harvesting wireless sensor networks (EH-WSNs) are being actively studied in order to solve the problems faced by battery-operated WSNs, namely the cost for battery replacement and the negative impact on the environment. In EH-WSNs, each node harvests ambient energy, such as light, heat, vibration, and uses it for sensing, computations, and wireless communications, where the amount of harvested energy of each node varies depending on their environments. MAC protocols for EH-WSNs need to be designed to achieve high throughput and fairness, however, the conventional MAC protocols proposed for EH-WSNs do not adapt to the harvesting rate of each node, resulting in poor fairness. In this paper, we propose a fair MAC protocol based on polling scheme for EH-WSNs. The proposed scheme adjusts contention probability of each node according to its harvesting rate, thereby increasing the throughput of nodes with low harvesting rate. We evaluate throughput and fairness of the proposed fair polling scheme by theoretical analysis and computer simulations, and show that the proposed scheme can improve fairness with little degradation of the overall network throughput.

Virtualization is no longer an emerging research area since the virtual processor and memory operate as efficiently as the physical ones. However, I/O performance is still restricted by the virtualization overhead caused by the costly and complex I/O virtualization mechanism, in particular by massive exits occurring on the guest-host switch and redundant processing of the I/O stacks at both guest and host. A para-virtual device driver may reduce the number of exits to the hypervisor, whereas the network stacks in the guest OS are still duplicated. Previous work proposed a socket-outsourcing technique that bypasses the redundant guest network stack by delivering the network request directly to the host. However, even by bypassing the redundant network paths in the guest OS, the obtained performance was still below 60% of the native device, since notifications of completion still depended on the hypervisor. In this paper, we propose vCanal, a novel network virtualization framework, to improve the performance of network access in the virtual machine toward that of the native machine. Implementation of vCanal reached 96% of the native TCP throughput, increasing the UDP latency by only 4% compared to the native latency.

Combining scheduled channel polling with channel diversity is a promising way for a MAC protocol to achieve high energy efficiency and performance under both light and heavy traffic conditions. However, the deafness problem may cancel out the benefit of channel diversity. In this paper, we first investigate the deafness problem of scheduled multi-channel polling MACs with experiments. Then we propose and evaluate two schemes to handle the deafness problem. Our experiment shows that deafness is a significant reason for performance degradation in scheduled multi-channel polling MACs. A proper scheme should be chosen depending on the traffic pattern and the design objective.

This paper presents a method to monitor information of a large-sized multicast group that can follow the group's dynamics in real-time while avoiding feedback implosion by using probabilistic polling. In particular, this paper improves the probabilistic-polling-based approach by deriving a reference mean value as the reference control value for the number of expected feedback from the properties of a binomial estimation model. As a result, our method adaptively changes its estimation parameters depending on the feedback from receivers in order to achieve a fast estimate time with high accuracy, while preventing the possible occurrence of feedback implosion. Our experimental implementation and evaluation on PlanetLab showed that the proposed method effectively controls the number of feedback and accurately estimates the size of a dynamic multicast group.

In the centralized polling mode in IEEE 802.16e, a base station (BS) polls mobile stations (MSs) for bandwidth reservation in one of three polling modes; unicast, multicast, or broadcast pollings. In unicast polling, the BS polls each individual MS to allow to transmit a bandwidth request packet. This paper presents an analytical model for the unicast polling of bandwidth request in IEEE 802.16e networks over Gilbert-Elliot error channel. We derive the probability distribution for the delay of bandwidth requests due to wireless transmission errors and find the loss probability of request packets due to finite retransmission attempts. By using the delay distribution and the loss probability, we optimize the number of polling slots within a frame and the maximum retransmission number while satisfying QoS on the total loss probability which combines two losses: packet loss due to the excess of maximum retransmission and delay outage loss due to the maximum tolerable delay bound. In addition, we obtain the utilization of polling slots, which is defined as the ratio of the number of polling slots used for the MS's successful transmission to the total number of polling slots used by the MS over a long run time. Analysis results are shown to well match with simulation results. Numerical results give examples of the optimal number of polling slots within a frame and the optimal maximum retransmission number depending on delay bounds, the number of MSs, and the channel conditions.

A microcellular network will be a good candidate for the future broadband mobile network. It is expected to support high-bit-rate connection for many fast mobile users if the handover is processed fast enough to lessen its impact on QoS requirements. One of the promising techniques is believed to use for the wireless interface in such a microcellular network is the WLAN (Wireless LAN) technique due to its very high wireless channel rate. However, the less capability of mobility support of this technique must be improved to be able to expand its utilization for the microcellular environment. The reason of its less support mobility is large handover latency delay caused by contention-based handover to the new BS (base station) and delay of re-forwarding data from the old to new BS. This paper presents a proposal of multi-polling and dynamic LMC (Logical Macro Cell) to reduce mentioned above delays. Polling frame for an MT (Mobile Terminal) is sent from every BS belonging to the same LMC -- a virtual single macro cell that is a multicast group of several adjacent micro-cells in which an MT is communicating. Instead of contending for the medium of a new BS during handover, the MT responds to the polling sent from that new BS to enable the transition. Because only one BS of the LMC receives the polling ACK (acknowledgement) directly from the MT, this ACK frame has to be multicast to all BSs of the same LMC through the terrestrial network to continue sending the next polling cycle at each BS. Moreover, when an MT hands over to a new cell, its current LMC is switched over to a newly corresponding LMC to prevent the future contending for a new LMC. By this way, an MT can do handover between micro-cells of an LMC smoothly because the redundant resource is reserved for it at neighboring cells, no need to contend with others. Our simulation results using the OMNeT++ simulator illustrate the performance achievements of the multi-polling and dynamic LMC scheme in eliminating handover latency, packet loss and keeping mobile users' throughput stable in the high traffic load condition though it causes somewhat overhead on the neighboring cells.

In this paper we propose a novel RFID anti-collision technique that intelligently combines polling and random access schemes. These two fundamentally different medium access control protocols are coherently integrated in our design while functionally complementing each other. The polling mode is designed to enable fast collision-free identification for the tags that exist within reader's coverage across the sessions. In contrast, the random access mode attempts to read the tags uncovered by the polling mode. Our proposed technique is particularly suited for a class of RFID applications in which a stationary reader periodically attempts to identify the tags with slow mobility. Numerical results show that our proposed technique yields much faster identification time against the existing approaches under various operating conditions.

Wide area ubiquitous wireless networks, which consist of access points (APs) connected to the fixed network and a great many wireless terminals (WTs), can offer a wide range of applications everywhere. In order to enhance network performance, we need to collect different kinds of data from as many WTs as possible; each AP must be capable of accommodating more than 103 WTs. This requirement can be achieved by employing DSA, a typical centralized media access control scheme, since it has high resource utilization efficiency. In this paper, we propose a novel DSA scheme that employs three new techniques to enhance throughput performance; (1) considering that most terminals tend to send data periodically, it employs both polling-based schemes, i.e. request-polling and data-polling, and a random access scheme. (2) In order to enhance bandwidth utilization effectiveness by polling, the polling timing is decided according to the data generation timing. (3) The AP decides the polled data size according to the latest distribution of data size and polls the WT for the data directly. If the data-polling size can not be determined with confidence, the AP uses request-polling instead of data-polling. Simulations verify that the proposed scheme offers better transmission performance than the existing schemes.

In this letter, a new segment-level speech/nonspeech classification method based on the Poisson polling technique is proposed. The proposed method makes two modifications from the baseline Poisson polling method to further improve the classification accuracy. One of them is to employ Poisson mixture models to more accurately represent various segmental patterns of the observed frequencies for frame-level input features. The other is the soft counting-based frequency estimation to improve the reliability of the observed frequencies. The effectiveness of the proposed method is confirmed by the experimental results showing the maximum error reduction of 39% compared to the segmentally accumulated log-likelihood ratio-based method.

In this paper, we present a polling scheme which allows for augmenting the support of voice communications in point co-ordination function (PCF) of IEEE 802.11 wireless networks. In this scheme, the Access Point (AP) of the Basic Service Set (BSS) maintains two polling lists, i.e. the talking list and the silence list. Based on the talking status of the stations identified via silence detection, two lists are dynamically adjusted by the AP. Temporary removal is applied to the stations in the silence list to further upgrade the performance. The conducted study based on simulation has shown that the proposed scheme can support more voice stations and has a lower packet loss rate than that obtained by four reference polling algorithms.

As an alternative solution to provide the quality of services (QoS) for broadband access over Ethernet Passive Optical Network (EPON), we present the usage of MAC control message for plural class queues and a traffic-class burst-polling based delta dynamic bandwidth allocation (DBA), referred to as TCBP-DDBA, scheme. For better QoS support, the TCBP-DDBA minimizes packet delays and delay variations for expedited forwarding packet and maximizes throughput for assured forwarding and best effort packets. The network resources are efficiently utilized and adaptively allocated to the three traffic classes for the given unbalanced traffic conditions by guaranteeing the requested QoS. Simulation results using OPNET show that the TCBP-DDBA scheme performs well in comparison to the conventional unit-based allocation scheme over the measurement parameters such as: packet delay, packet delay variation, and channel utilization.

In medium access control (MAC) protocols for wireless local area networks (WLANs), the Round-Robin scheme is the general polling scheme. A major drawback of this scheme is that it is inefficient when only a small number of stations have packets to transmit. This inefficiency is caused by polling stations that have no packets to transmit. This paper proposes an effective and simple polling scheme to reduce the number of polling times for a station with no packets to transmit. For example, the simulation result shows that the throughput increases by 35.8% when fifteen stations out of thirty stations in the polling list have packets to transmit at IEEE 802.11a 54 Mbps rate.

Polling I/O mechanisms on the Unix platform such as select() and poll() cause high processing overhead when they are used in a heavily-loaded network server with many concurrent open sockets. Large waste of processing power incurs not only service degradation but also various troubles such as high electronic power consumption and worsened MTBF of server hosts. It is thus a serious issue especially in large-scale service providers such as an Internet data center (iDC) where a great number of heavily-loaded network servers are operated. As a solution of this problem, we propose a technique of fine-grained control on the invocation intervals of the polling I/O function. The uniqueness of this study is the utilization of POSIX real-time scheduling to enable the fine-grained execution control. Although earlier solutions such as an explicit event delivery mechanism also addressed the problem, they require major modification in the OS kernel and transition from the traditional polling I/O model to the new explicit event-notification model. On the other hand, our technique can be implemented with low cost because it just inserts a few small blocks of codes into the server program and does not require any modification in the OS kernel.

The authors study the performance of a disk storing WWW data by using a broadcast polling model. The model has single message queues, an exponential server and asymmetric exponential arrivals. Numerical examples show that the analytical results are close to the simulation results.

Randomly addressed polling was proposed as a multiple access control protocol for wireless local area networks (LANs). However, the protocol has difficulties in supporting real-time services such as voice transmission. We propose a reservation scheme and make it possible to support real-time services. The scheme is described in detail. Efficiency and average access delay are analyzed.

In this paper, we propose a polling-based scheduling strategy for multiple access control in wireless ATM networks (POSTMAN). A pure centrally controlled polling scheme is adopted in our protocol, therefore no contention channel is needed. The POSTMAN protocol assumes a TDMA/TDD frame format, by which wireless bandwidth is allocated flexibly both among multiple mobile terminals and between downlink and uplink channels. When polling the uplink traffic, the POSTMAN needs no priori traffic model to predict the cell arrivals. Instead, a token queue and an ABR buffer status table are used in the base station. Simulation results show that the POSTMAN protocol is robust in most cases and can work steadily under very high network load conditions.

Network monitoring is one of the most significant functions in network management to understand the state of a network in real-time. In SNMP (Simple Network Management Protocol), polling is used for this purpose. If the time interval for two consecutive polling requests is too long, then we cannot understand the state of the network in real-time. Conversely, if it is too short, then the polling message traffic increases and imposes a heavy load on the network. Many dynamic polling algorithms have been proposed for controlling the increase in the polling message traffic. However, they cannot keep track of the time variations of management information values, since their main objectives are to check whether or not a network node is active and the next polling interval is determined being independent of the time variations of the values. The existing polling algorithms are thereby not applicable to the case where monitoring the time variation of management information values is critical. This paper proposes a new dynamic polling algorithm which, by making use of Discrete Fourier Transformation, enables not only to control the increase in the polling message traffic but also to keep track of the time variations of network management information values. We show the availability of the proposed algorithm by evaluating it through both simulations and experiments in actual network environment.

In this paper, we first prove that the Randomly Addressed Polling (RAP) protocol is unstable under the random access channel with heavy traffic. We also show that network stability can be ensured by controlling the arrival rate λ or by expanding the available addresses p on the assumption that there are M finite stations within the coverage of the controller (the base station). From analyses and results, we see the equilibrium of arrival rate is inversely proportional to the product of users (stations) and the exponent of stations. We also see that the maximum throughput can be derived at the point of λ1/M. This maximum performance can be easily obtained under the consideration of RAP protocol's stability. It also implies that the maximum throughput is independent of the available addresses of RAP protocol when pM.