Measurements of Data Plane Reliability and Performance

The southbound protocol of Software Defined Networking (SDN) enables the direct access into SDN switches which accelerates the innovation and deployment of network functions in the data plane. Correspondingly, SDN switches that support the new southbound protocol and provide high performance are developed continuously. Therefore, there is an increasing need for testing tools to test such equipment in terms of protocol correctness and performance. However, existing tools have deficiencies in flexibility for verifying the novel southbound protocol, time synchronization between the two planes, and supporting more testing functions with less resource consumption. In this paper, we present the concept of CPU & FPGA co-design Tester (CFT) for SDN switches, which provides flexible APIs for test cases of the control plane and high performance for testing functions in the data plane. We put forward an efficient scheduling algorithm to integrate the control plane and the data plane into a single pipeline which fundamentally solves the time asynchronization between these two planes. Due to the reconfigurable feature of our proposed pipeline, it becomes possible to perform different testing functions in one pipeline. Through a prototype implementation and evaluation, we reveal that the proposed CFT can verify the protocol correctness of SDN switches on the control plane while providing no-worse performance for tests on the data plane compared with commercial testers.

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A Software-Defined Architecture for Integrating Heterogeneous Space and Ground Networks

Frontiers in Communications and Networks ◽

10.3389/frcmn.2021.717476 ◽

2021 ◽

Vol 2 ◽

Author(s):

Jie Sun ◽

Feng Liu ◽

Yong Li ◽

Lianlian Zhang ◽

Dingyuan Shi

Keyword(s):

Heterogeneous Networks ◽

Physical Layer ◽

Collaborative Optimization ◽

Software Defined Network ◽

Multiple Networks ◽

Data Plane ◽

Efficient Control ◽

Integrated Architecture ◽

Multi Level ◽

And Performance

In recent years, various types of heterogeneous networks develop rapidly. The integration of multi-type networks have great values in the fields of military and civil applications. The challenges of integrating multiple networks covers the heterogeneity of multiple aspects, e.g., the architectures, protocols, and switching mechanisms. The existing interconnection technologies of heterogeneous networks mainly include traditional static protocol gateways, traditional software-defined network (SDN) gateways, and improved SDN gateways. However, traditional static protocol gateways need to be customed in advance according to specific scenarios, which leads to the lack of flexibility. Traditional SDN gateways are often used for connecting homogeneous networks. The existing improved SDN gateways often neglect the efficiency and cost of integrating heterogeneous networks. In our work, we propose a software-defined architecture for integrating heterogeneous space and ground networks (SD-SGN). First, we propose an integrated architecture that utilizes SDN gateways and southbound interfaces to shield subnets’ heterogeneity ranging from the physical layer to the network layer. Second, we use the multi-class multi-level flow tables to provide a flexible data plane. Third, we offer an efficient control plane based on the subnet abstraction and global collaborative optimization. Fourth, we give a further discussion on customizing a complete network service based on the proposed SDN architecture. Last, extensive simulations demonstrate that this SDN architecture is effective and performs well in terms of costs, efficiency, and performance.

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Linux Software Router: Data Plane Optimization and Performance Evaluation

Journal of Networks ◽

10.4304/jnw.2.3.6-17 ◽

2007 ◽

Vol 2 (3) ◽

Cited By ~ 31

Author(s):

Raffaele Bolla ◽

Roberto Bruschi

Keyword(s):

Performance Evaluation ◽

Data Plane ◽

And Performance ◽

Optimization And Performance

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Transmission Scanning Electron Microscopy and Energy Analysis with the Siemens ELMISKOP 101

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095509 ◽

1972 ◽

Vol 30 ◽

pp. 450-451

Author(s):

H. M. Thieringer

Keyword(s):

Objective Lens ◽

Transmission Microscopy ◽

Image Recording ◽

Mode Of Operation ◽

Scanning Transmission ◽

Electron Microscopes ◽

And Performance ◽

Convergent Beam ◽

Ray Path ◽

Beam Diffraction

It has repeatedly been show that with conventional electron microscopes very fine electron probes can be produced, therefore allowing various micro-techniques such as micro recording, X-ray microanalysis and convergent beam diffraction. In this paper the function and performance of an SIEMENS ELMISKOP 101 used as a scanning transmission microscope (STEM) is described. This mode of operation has some advantages over the conventional transmission microscopy (CTEM) especially for the observation of thick specimen, in spite of somewhat longer image recording times.Fig.1 shows schematically the ray path and the additional electronics of an ELMISKOP 101 working as a STEM. With a point-cathode, and using condensor I and the objective lens as a demagnifying system, an electron probe with a half-width ob about 25 Å and a typical current of 5.10-11 amp at 100 kV can be obtained in the back focal plane of the objective lens.

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Angular Resolved Electron Spectroscopy with Parallel Recording

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100135459 ◽

1990 ◽

Vol 48 (2) ◽

pp. 370-371

Author(s):

Huang Min ◽

P.S. Flora ◽

C.J. Harland ◽

J.A. Venables

Keyword(s):

Electron Spectroscopy ◽

Low Voltage ◽

Solid Angle ◽

Detection System ◽

Voltage Electron ◽

Cylindrical Mirror ◽

Inner Radius ◽

Channel Plate ◽

And Performance ◽

Type Detector

A cylindrical mirror analyser (CMA) has been built with a parallel recording detection system. It is being used for angular resolved electron spectroscopy (ARES) within a SEM. The CMA has been optimised for imaging applications; the inner cylinder contains a magnetically focused and scanned, 30kV, SEM electron-optical column. The CMA has a large inner radius (50.8mm) and a large collection solid angle (Ω > 1sterad). An energy resolution (ΔE/E) of 1-2% has been achieved. The design and performance of the combination SEM/CMA instrument has been described previously and the CMA and detector system has been used for low voltage electron spectroscopy. Here we discuss the use of the CMA for ARES and present some preliminary results.The CMA has been designed for an axis-to-ring focus and uses an annular type detector. This detector consists of a channel-plate/YAG/mirror assembly which is optically coupled to either a photomultiplier for spectroscopy or a TV camera for parallel detection.

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Novel epoxy/anhydride alternatives for biological electron microscopy: Physical and performance characteristis of embed 812 and LX 112 in combination with NSA/NMA/DMAE

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100156985 ◽

1989 ◽

Vol 47 ◽

pp. 1000-1001

Author(s):

Joe A. Mascorro ◽

Gerald S. Kirby

Keyword(s):

Electron Microscopy ◽

Flow Rate ◽

Succinic Anhydride ◽

Volume Flow Rate ◽

Mass Density ◽

Uranyl Acetate ◽

Volume Flow ◽

Base Resin ◽

And Performance ◽

Acid Anhydrides

Embedding media based upon an epoxy resin of choice and the acid anhydrides dodecenyl succinic anhydride (DDSA), nadic methyl anhydride (NMA), and catalyzed by the tertiary amine 2,4,6-Tri(dimethylaminomethyl) phenol (DMP-30) are widely used in biological electron microscopy. These media possess a viscosity character that can impair tissue infiltration, particularly if original Epon 812 is utilized as the base resin. Other resins that are considerably less viscous than Epon 812 now are available as replacements. Likewise, nonenyl succinic anhydride (NSA) and dimethylaminoethanol (DMAE) are more fluid than their counterparts DDSA and DMP- 30 commonly used in earlier formulations. This work utilizes novel epoxy and anhydride combinations in order to produce embedding media with desirable flow rate and viscosity parameters that, in turn, would allow the medium to optimally infiltrate tissues. Specifically, embeding media based on EmBed 812 or LX 112 with NSA (in place of DDSA) and DMAE (replacing DMP-30), with NMA remaining constant, are formulated and offered as alternatives for routine biological work.Individual epoxy resins (Table I) or complete embedding media (Tables II-III) were tested for flow rate and viscosity. The novel media were further examined for their ability to infilftrate tissues, polymerize, sectioning and staining character, as well as strength and stability to the electron beam and column vacuum. For physical comparisons, a volume (9 ml) of either resin or media was aspirated into a capillary viscocimeter oriented vertically. The material was then allowed to flow out freely under the influence of gravity and the flow time necessary for the volume to exit was recored (Col B,C; Tables). In addition, the volume flow rate (ml flowing/second; Col D, Tables) was measured. Viscosity (n) could then be determined by using the Hagen-Poiseville relation for laminar flow, n = c.p/Q, where c = a geometric constant from an instrument calibration with water, p = mass density, and Q = volume flow rate. Mass weight and density of the materials were determined as well (Col F,G; Tables). Infiltration schedules utilized were short (1/2 hr 1:1, 3 hrs full resin), intermediate (1/2 hr 1:1, 6 hrs full resin) , or long (1/2 hr 1:1, 6 hrs full resin) in total time. Polymerization schedules ranging from 15 hrs (overnight) through 24, 36, or 48 hrs were tested. Sections demonstrating gold interference colors were collected on unsupported 200- 300 mesh grids and stained sequentially with uranyl acetate and lead citrate.

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Trace nanoanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100172437 ◽

1994 ◽

Vol 52 ◽

pp. 940-941

Author(s):

D. E. Newbury ◽

R. D. Leapman

Keyword(s):

High Performance ◽

Secondary Ion Mass Spectrometry ◽

Detection Efficiency ◽

Volume Element ◽

And Performance ◽

Trace Constituents ◽

Secondary Ion ◽

Concentration Levels ◽

Structure Properties

Trace constituents, which can be very loosely defined as those present at concentration levels below 1 percent, often exert influence on structure, properties, and performance far greater than what might be estimated from their proportion alone. Defining the role of trace constituents in the microstructure, or indeed even determining their location, makes great demands on the available array of microanalytical tools. These demands become increasingly more challenging as the dimensions of the volume element to be probed become smaller. For example, a cubic volume element of silicon with an edge dimension of 1 micrometer contains approximately 5×1010 atoms. High performance secondary ion mass spectrometry (SIMS) can be used to measure trace constituents to levels of hundreds of parts per billion from such a volume element (e. g., detection of at least 100 atoms to give 10% reproducibility with an overall detection efficiency of 1%, considering ionization, transmission, and counting).

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