Latency (engineering)

About: Latency (engineering) is a research topic. Over the lifetime, 3729 publications have been published within this topic receiving 39210 citations. The topic is also known as: lag.

A Covert Communication Model Based on Least Significant Bits Steganography in Voice over IP

Abstract: Steganography, as one of alternative techniques for secure communications, has drawn more and more attentions. This paper presents a covert communication model based on least significant bits (LSB) steganography in Voice over IP (VoIP). The model aims at providing nice security of secret messages and real-time performance that is vital for VoIP. Therefore, we employ a simple encryption of secret messages before embedding them. This encryption strikes a good balance between adequate short-term protection for secret messages and low latency for VoIP. Furthermore, we design a structure of embedded messages. It can provide flexible length and avoid effectually both extraction attack and deceptive attack. We evaluate the model with ITU-T G.729a as the codec of the cover speech in StegTalk, our platform for study on covert communications theory in VoIP. In this case, the proposed model can provide two optional covert transmission speeds, i.e. 0.8 kb/s and 2.6 kb/s, where the maximum payload ratio is 99.98%. The experimental results show that our method has negligible effects on speech quality and well meets the real-time requirement of VoIP.

Active Replication at (Almost) No Cost

Abstract: MapReduce has become a popular programming paradigm in the domain of batch processing systems. Its simplicity allows applications to be highly scalable and to be easily deployed on large clusters. More recently, the MapReduce approach has been also applied to Event Stream Processing (ESP) systems. This approach, which we call StreamMapReduce, enabled many novel applications that require both scalability and low latency. Another recent trend is to move distributed applications to public clouds such as Amazon EC2 rather than running and maintaining private data centers. Most cloud providers charge their customers on an hourly basis rather than on CPU cycles consumed. However, many applications, especially those that process online data, need to limit their CPU utilization to conservative levels (often as low as $50\%$) to be able to accommodate natural and sudden load variations without causing unacceptable deterioration in responsiveness. In this paper, we present a new fault tolerance approach based on active replication for StreamMapReduce systems. This approach is cost effective for cloud consumers as well as cloud providers. Cost effectiveness is achieved by fully utilizing the acquired computational resources without performance degradation and by reducing the need for additional nodes dedicated to fault tolerance.

Iris: A hybrid nanophotonic network design for high-performance and low-power on-chip communication

Abstract: On-chip communication, including short, often-multicast, latency-critical coherence and synchronization messages, and long, unicast, throughput-sensitive data transfers, limits the power efficiency and performance scalability of many-core chip-multiprocessor systems. This article analyzes on-chip communication challenges and studies the characteristics of existing electrical and emerging nanophotonic interconnect. Iris, a CMOS-compatible high-performance low-power nanophotonic on-chip network, is thus introduced. Iris's circuit-switched subnetwork supports throughput-sensitive data transfer. Iris's optical-antenna-array-based broadcast--multicast subnetwork optimizes latency-critical traffic and supports the path setup of circuit-switched communication. Overall, the proposed nanophotonic network design offers an on-chip communication backplane that is power efficient while demonstrating low latency and high throughput.

Reinforcement Learning Based Scheduling Algorithm for Optimizing Age of Information in Ultra Reliable Low Latency Networks

Abstract: Age of Information (AoI) measures the freshness of the information at a remote location. AoI reflects the time that is elapsed since the generation of the packet by a transmitter. In this paper, we consider a remote monitoring problem (e.g., remote factory) in which a number of sensor nodes are transmitting time sensitive measurements to a remote monitoring site. We consider minimizing a metric that maintains a trade-off between minimizing the sum of the expected AoI of all sensors and minimizing an Ultra Reliable Low Latency Communication (URLLC) term. The URLLC term is considered to ensure that the probability the AoI of each sensor exceeds a predefined threshold is minimized. Moreover, we assume that sensors tolerate different threshold values and generate packets at different sizes. Motivated by the success of machine learning in solving large networking problems at low complexity, we develop a low complexity reinforcement learning based algorithm to solve the proposed formulation. We trained our algorithm using the state-of-the-art actor-critic algorithm over a set of public bandwidth traces. Simulation results show that the proposed algorithm outperforms the considered baselines in terms of minimizing the expected AoI and the threshold violation of each sensor.

Data transfer, synchronising applications, and low latency networks

Abstract: Asynchronous network interface and method of synchronisation between two applications on different computers is provided. The network interface contains snooping hardware which can be programmed to contain triggering values comprising either addresses, address ranges or other data which are to be matched. These data are termed “trip wires”. Once programmed, the interface monitors the data stream, including address data, passing through the interface for addresses and data which match the trip wires which have been set. On a match, the snooping hardware can generate interrupts, increment event counters, or perform some other application-specified action. This snooping hardware is preferably based upon Content-Addressable Memory. The invention thus provides in-band synchronisation by using synchronisation primitives which are programmable by user level applications, while still delivering high bandwidth and low latency. The programming of the synchronisation primitives can be made by the sending and receiving applications independently of each other and no synchronisation information is required to traverse the network.