3,806 research outputs found
Challenges Using the Linux Network Stack for Real-Time Communication
Starting in the early 2000s, human-in-the-loop (HITL) simulation groups at NASA and the Air Force Research Lab began using the Linux network stack for some real-time communication. More recently, SpaceX has adopted Ethernet as the primary bus technology for its Falcon launch vehicles and Dragon capsules. As the Linux network stack makes its way from ground facilities to flight critical systems, it is necessary to recognize that the network stack is optimized for communication over the open Internet, which cannot provide latency guarantees. The Internet protocols and their implementation in the Linux network stack contain numerous design decisions that favor throughput over determinism and latency. These decisions often require workarounds in the application or customization of the stack to maintain a high probability of low latency on closed networks, especially if the network must be fault tolerant to single event upsets
CloudJet4BigData: Streamlining Big Data via an Accelerated Socket Interface
Big data needs to feed users with fresh processing results and cloud platforms can be used to speed up big data applications. This paper describes a new data communication protocol (CloudJet) for long distance and large volume big data accessing operations to alleviate the large latencies encountered in sharing big data resources in the clouds. It encapsulates a dynamic multi-stream/multi-path engine at the socket level, which conforms to Portable Operating System Interface (POSIX) and thereby can accelerate any POSIX-compatible applications across IP based networks. It was demonstrated that CloudJet accelerates typical big data applications such as very large database (VLDB), data mining, media streaming and office applications by up to tenfold in real-world tests
Teleoperation of passivity-based model reference robust control over the internet
This dissertation offers a survey of a known theoretical approach and novel experimental results in establishing a live communication medium through the internet to host a virtual communication environment for use in Passivity-Based Model Reference Robust Control systems with delays. The controller which is used as a carrier to support a robust communication between input-to-state stability is designed as a control strategy that passively compensates for position errors that arise during contact tasks and strives to achieve delay-independent stability for controlling of aircrafts or other mobile objects. Furthermore the controller is used for nonlinear systems, coordination of multiple agents, bilateral teleoperation, and collision avoidance thus maintaining a communication link with an upper bound of constant delay is crucial for robustness and stability of the overall system. For utilizing such framework an elucidation can be formulated by preparing site survey for analyzing not only the geographical distances separating the nodes in which the teleoperation will occur but also the communication parameters that define the virtual topography that the data will travel through. This survey will first define the feasibility of the overall operation since the teleoperation will be used to sustain a delay based controller over the internet thus obtaining a hypothetical upper bound for the delay via site survey is crucial not only for the communication system but also the delay is required for the design of the passivity-based model reference robust control. Following delay calculation and measurement via site survey, bandwidth tests for unidirectional and bidirectional communication is inspected to ensure that the speed is viable to maintain a real-time connection. Furthermore from obtaining the results it becomes crucial to measure the consistency of the delay throughout a sampled period to guarantee that the upper bound is not breached at any point within the communication to jeopardize the robustness of the controller. Following delay analysis a geographical and topological overview of the communication is also briefly examined via a trace-route to understand the underlying nodes and their contribution to the delay and round-trip consistency. To accommodate the communication channel for the controller the input and output data from both nodes need to be encapsulated within a transmission control protocol via a multithreaded design of a robust program within the C language. The program will construct a multithreaded client-server relationship in which the control data is transmitted. For added stability and higher level of security the channel is then encapsulated via an internet protocol security by utilizing a protocol suite for protecting the communication by authentication and encrypting each packet of the session using negotiation of cryptographic keys during each session
Design of a Hybrid Modular Switch
Network Function Virtualization (NFV) shed new light for the design,
deployment, and management of cloud networks. Many network functions such as
firewalls, load balancers, and intrusion detection systems can be virtualized
by servers. However, network operators often have to sacrifice programmability
in order to achieve high throughput, especially at networks' edge where complex
network functions are required.
Here, we design, implement, and evaluate Hybrid Modular Switch (HyMoS). The
hybrid hardware/software switch is designed to meet requirements for modern-day
NFV applications in providing high-throughput, with a high degree of
programmability. HyMoS utilizes P4-compatible Network Interface Cards (NICs),
PCI Express interface and CPU to act as line cards, switch fabric, and fabric
controller respectively. In our implementation of HyMos, PCI Express interface
is turned into a non-blocking switch fabric with a throughput of hundreds of
Gigabits per second.
Compared to existing NFV infrastructure, HyMoS offers modularity in hardware
and software as well as a higher degree of programmability by supporting a
superset of P4 language
GPUs as Storage System Accelerators
Massively multicore processors, such as Graphics Processing Units (GPUs),
provide, at a comparable price, a one order of magnitude higher peak
performance than traditional CPUs. This drop in the cost of computation, as any
order-of-magnitude drop in the cost per unit of performance for a class of
system components, triggers the opportunity to redesign systems and to explore
new ways to engineer them to recalibrate the cost-to-performance relation. This
project explores the feasibility of harnessing GPUs' computational power to
improve the performance, reliability, or security of distributed storage
systems. In this context, we present the design of a storage system prototype
that uses GPU offloading to accelerate a number of computationally intensive
primitives based on hashing, and introduce techniques to efficiently leverage
the processing power of GPUs. We evaluate the performance of this prototype
under two configurations: as a content addressable storage system that
facilitates online similarity detection between successive versions of the same
file and as a traditional system that uses hashing to preserve data integrity.
Further, we evaluate the impact of offloading to the GPU on competing
applications' performance. Our results show that this technique can bring
tangible performance gains without negatively impacting the performance of
concurrently running applications.Comment: IEEE Transactions on Parallel and Distributed Systems, 201
APEnet+: a 3D toroidal network enabling Petaflops scale Lattice QCD simulations on commodity clusters
Many scientific computations need multi-node parallelism for matching up both
space (memory) and time (speed) ever-increasing requirements. The use of GPUs
as accelerators introduces yet another level of complexity for the programmer
and may potentially result in large overheads due to the complex memory
hierarchy. Additionally, top-notch problems may easily employ more than a
Petaflops of sustained computing power, requiring thousands of GPUs
orchestrated with some parallel programming model. Here we describe APEnet+,
the new generation of our interconnect, which scales up to tens of thousands of
nodes with linear cost, thus improving the price/performance ratio on large
clusters. The project target is the development of the Apelink+ host adapter
featuring a low latency, high bandwidth direct network, state-of-the-art wire
speeds on the links and a PCIe X8 gen2 host interface. It features hardware
support for the RDMA programming model and experimental acceleration of GPU
networking. A Linux kernel driver, a set of low-level RDMA APIs and an OpenMPI
library driver are available, allowing for painless porting of standard
applications. Finally, we give an insight of future work and intended
developments
KuberneTSN: a Deterministic Overlay Network for Time-Sensitive Containerized Environments
The emerging paradigm of resource disaggregation enables the deployment of
cloud-like services across a pool of physical and virtualized resources,
interconnected using a network fabric. This design embodies several benefits in
terms of resource efficiency and cost-effectiveness, service elasticity and
adaptability, etc. Application domains benefiting from such a trend include
cyber-physical systems (CPS), tactile internet, 5G networks and beyond, or
mixed reality applications, all generally embodying heterogeneous Quality of
Service (QoS) requirements. In this context, a key enabling factor to fully
support those mixed-criticality scenarios will be the network and the
system-level support for time-sensitive communication. Although a lot of work
has been conducted on devising efficient orchestration and CPU scheduling
strategies, the networking aspects of performance-critical components remain
largely unstudied. Bridging this gap, we propose KuberneTSN, an original
solution built on the Kubernetes platform, providing support for time-sensitive
traffic to unmodified application binaries. We define an architecture for an
accelerated and deterministic overlay network, which includes kernel-bypassing
networking features as well as a novel userspace packet scheduler compliant
with the Time-Sensitive Networking (TSN) standard. The solution is implemented
as tsn-cni, a Kubernetes network plugin that can coexist alongside popular
alternatives. To assess the validity of the approach, we conduct an
experimental analysis on a real distributed testbed, demonstrating that
KuberneTSN enables applications to easily meet deterministic deadlines,
provides the same guarantees of bare-metal deployments, and outperforms overlay
networks built using the Flannel plugin.Comment: 6 page
- …