Overhead (computing)

About: Overhead (computing) is a research topic. Over the lifetime, 33792 publications have been published within this topic receiving 456227 citations.

PiggyData: reducing CSMA/CA collisions for multimedia and TCP connections

Abstract: This paper presents a scheme to improve the efficiency of radio MAC protocols in the case of bidirectional connections, like TCP connections and multimedia streams. First, the impact of directionality over the contention process is analysed. Then the PiggyData scheme is presented, which decreases the collision rate and overhead of bidirectional traffic over MAC protocols based on CSMA/CA. Finally, the new protocol is simulated in various scenarios to show how it performs.

Embedding Nonblocking Multicast Virtual Networks in Fat-Tree Data Centers

Abstract: Virtualization of servers and networks is a key technique to resolve the conflict between the increasing demands on computing power and the high cost of hardware in data centers. In order to map virtual networks to physical infrastructure efficiently, designers have to make careful decisions on the allocation of limited resources, which makes network embedding in data centers a very important problem. In this paper, we tackle the network embedding problem in fat-tree data centers. To meet the requirements of instant parallel data transfer between multiple computing units, we propose a model of multicast-capable virtual networks (Mons). We then design three virtual machine (VM) placement schemes with different features for embedding MVNs into fat-tree DCNs, named Most-Vacant-Fit (MVF), Most-Compact-First (MCF) and Mixed-Bidirectional-Fill (MBF). All these VM placement schemes guarantee the no blocking multicast capability of each MVN while simultaneously achieving significant saving on the cost of network hardware. In addition, each VM placement scheme also has its unique features. The MVF scheme has zero interference to existing computing tasks in data centers, the MCF scheme leads to the greatest cost saving, the MBF scheme simultaneously possesses the merits of MVF and MCF, and it provides an adjustable parameter allowing cloud providers to achieve preferred balance between the cost and the overhead. Finally, we compare the performance and overhead of these VM placement schemes, and present simulation results to validate our theoretical results.

Method and device for transmitting/receiving monitoring information and transfer system

Abstract: The invention discloses a method and a device for transmitting/receiving monitoring information and a transfer system. The method for transmitting the monitoring information comprises the following steps: a network element maps a received low-order optical path data unit (ODU) signal according to the GMP to acquire a specified high-order ODU signal, and the high-order ODU signal comprises idle bytes and an overhead part; the network element fills GCC bytes in the idle bytes, wherein the content in the GCC bytes is monitoring information to be transmitted; the network element fills Cn in the overhead part; and the network element maps the high-order ODU signal into an OTU signal and transmits the OTU signal. The invention can transfer the monitoring information under the premise of not occupying overhead, thereby solving the problem of large limitation in the transfer of the monitoring information and increasing the monitoring bandwidth. The invention has stronger practical value.

Overhead lines suspension state detecting and monitoring device and working method thereof

Abstract: The invention provides an overhead lines suspension state detecting and monitoring device and a working method thereof, wherein the overhead lines suspension state detecting and monitoring device comprises a positioning triggering device and a shooting device; the positioning triggering device is used for triggering the shooting device to snap-shot an front image of an overhead lines suspension system when detecting that the distance between a detection vehicle and the overhead lines suspension system in the driving direction reaches a first threshold, and triggering the shooting device to snap-shot a back image of the overhead lines suspension system when detecting that distance between the detection vehicle and the overhead lines suspension system reaches a second threshold after the detection vehicle passes the overhead lines suspension system; the shooting device is connected with the positioning triggering device, and is used for snap-shooting the front image and the back image of the overhead lines suspension system. The overhead lines suspension state detecting and monitoring device solves the technical problems of overcomplicated detection process, poor detection efficiency and low accuracy due to the manual detecting on the overhead lines suspension system, and achieves the technical effects of effectively improving the detection efficiency and the accuracy of detection results.