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Network Virtualization Overlays (NVO3) provides multi-tenancy services in cloud data centers with existing networking equipment. IP tunneling is an essential technology to logically separate each virtual traffic, in particular, Stateless Transport Tunneling (STT) is considered to achieve better performance using TCP Segmentation Offload (TSO) feature. Currently, there is no openly available implementation...
Virtualization provides the function of saving the whole execution environment status of the running virtual machine (VM), which makes check pointing flexible and practical for HPC servers or data center servers. However, the system-level check pointing needs to save a large number of data to the disk. Moreover, the overhead grows linearly with the increasing size of virtual machine memory, which...
Virtual Machine Cluster (VMC) is now widely used to host network applications due to its well scalability and high availability compared to physical cluster. To provide fault tolerance, VMC snapshot is one well known technique, it saves the entire VMC state into stable storage and rollbacks the VM from the latest saved state upon failures. However, due to the large snapshot size as well as numerous...
In Infrastructure-as-a-Service (IaaS) clouds, users remotely manage the systems in virtual machines (VMs) called user VMs, e.g., Through VNC. To allow users to manage their VMs even on failures inside the VMs, IaaS usually provides out-of-band remote management. This VM management is performed indirectly via a VNC server in a privileged VM called the management VM. However, it is discontinued when...
While many cloud providers today offer powerful computing infrastructure as a service, and enterprises are already making routine use of it, the adoption of cloud computing for engineering and scientific applications is lagging behind. Despite the many benefits cloud resources provide, reasons for this slow adoption are many: complex access to clouds, inflexible software licensing, time-consuming...
Hypervisors are becoming increasingly ubiquitous with the growing proliferation of virtualized data centers. As a result, attackers are exploring vectors to attack hypervisors, against which an attack may be executed via several attack vectors such as device drivers, virtual machine exit events, or hyper calls. Hyper calls enable intrusions in hypervisors through their hyper call interfaces. Despite...
To reduce CPU, memory and bandwidth usage as cloud platform security consumption, and to prevent vulnerabilities that brought in by VM based antivirus software, we propose an agentless processes monitoring architecture for cloud platform. To demonstrate this architecture, we modified KVM kernel, programed OpenStack plugins, added security module on both management and compute node in a cloud platform...
Nowadays, cloud providers of "Infrastructure as a service" require datacenter networks to support virtualization and multi-tenancy at large scale, while it brings a grand challenge to datacenters. Traditional network technologies of datacenters and common commodity devices of network can not meet these new needs. In this paper, we present NVLAN, a novel VLAN technology for scalable multi-tenant...
In many scientific and computational domains, graphs are used to represent and analyze data. Such graphs often exhibit the characteristics of small-world networks: few high-degree vertexes connect many low-degree vertexes. Despite the randomness in a graph search, it is possible to capitalize on this characteristic and cache relevant information in high-degree vertexes. We applied this idea by caching...
With the emergence of multi-core and multi-socket non-uniform memory access (NUMA) platforms in recent years, new software challenges have arisen to use them efficiently. In the field of high performance computing (HPC), parallel programming has always been the key factor to improve applications performance. However, the implications of parallel architectures in the system software has been overlooked...
Energy consumption and total cost of ownership are daunting challenges for Datacenters, because they scale disproportionately with performance. Datacenters running financial analytics may incur extremely high operational costs in order to meet performance and latency requirements of their hosted applications. Recently, ARM-based microservers have emerged as a viable alternative to high-end servers,...
Almost all DNS queries that traverse Internet are transported via UDP in self-contained small packages. Therefore, with no restriction of packet ordering, the intuition would say that adding thread-based parallelism to the servers will increase their performance, but it does not. This paper studies the problem of serialized access to UDP sockets, and states the problem in the way the packets are enqueued...
The purpose of this article is to describe characteristics of obfuscated network buffer overflow attacks in contrast with characteristics of directly simulated attacks. The obfuscation was performed by tunneling of malicious traffic in HTTP and HTTPS protocols. These protocols wrap a malicious communication between an attacker situated outside of an intranet and a callback located inside of an intranet...
Much attention has been given to the efficient execution of the scale-out applications that dominate in datacenter computing. However, the effects of the hardware support in the Memory Management Unit (MMU) in combination with the distinct characteristics of the scale-out applications have been largely ignored until recently. In this paper, we comprehensively quantify the MMU overhead on a real machine...
The growth in datacenter computing has increased the importance of energy-efficiency in servers. Techniques to reduce power have brought server designs close to achieving energy-proportional computing. However, they stress the inherent tradeoff between aggressive power management and quality of service (QoS) — the dominant metric of performance in datacenters. In this paper, we characterize this tradeoff...
TCP Cubic is designed to better utilize high bandwidth-delay product paths in IP networks. It is currently the default TCP version in the Linux kernel. Our objective in this work is to better understand the performance of TCP Cubic in scenarios with a large number of competing long-lived TCP flows, as can be observed, e.g., in cloud environments. In such situations, Cubic connections tend to synchronize...
For any network connection, the data throughput of the end device is related to its TCP (Transmission Control Protocol) buffer size, network latency and network bandwidth. In regions where open market devices are popular like European and Asian markets, the devices come with a static value of buffer sizes that are independent of operator's network conditions consequently resulting in either low throughput...
When a software system starts behaving abnormally during normal operations, system administrators resort to the use of logs, execution traces, and system scanners (e.g., anti-malwares, intrusion detectors, etc.) to diagnose the cause of the anomaly. However, the unpredictable context in which the system runs and daily emergence of new software threats makes it extremely challenging to diagnose anomalies...
Given the current situation on the Internet, it is important to determine the trust of the communication routes between a client and server. Such determination can only be established by end terminals such as clients and servers, not by intermediate routers or network providers so far. The revelations regarding PRISM and other programs highlight the importance of this issue. In this paper, a method...
In order to leverage the full potential of video playback capabilities in modern connected devices new protocols for content delivery are emerging. Sat>IP protocol is gaining popularity as a new IP-based architecture for reception and distribution of satellite signal. In this paper we present implementation of Sat>IP server on Linux embedded platform and propose programming techniques which...
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