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Abstract-As the service requirements of network applications shift from high throughput to high media quality, interactivity, and responsiveness, the definition of QoE (Quality of Experience) has become multidimensional. Although it may not be difficult to measure individual dimensions of the QoE, how to capture users' overall perceptions when they are using network applications remains an open question.In this paper, we propose a framework called OneClick to capture users' perceptions when they are using network applications. The framework only requires a subject to click a dedicated key whenever he/she feels dissatisfied with the quality of the application in use. OneClick is particularly effective because it is intuitive, lightweight, efficient, time-aware, and application-independent. We use two objective quality assessment methods, PESQ and VQM, to validate OneClick's ability to evaluate the quality of audio and video clips. To demonstrate the proposed framework's efficiency and effectiveness in assessing user experiences, we implement it on two applications, one for instant messaging applications, and the other for firstperson shooter games. A Flash implementation of the proposed framework is also presented.

The virtual switch is the cornerstone of the today's virtualized data center. As all traffic to and from virtual machines or containers must pass through a vSwitch, it is the ideal location for network configuration and policy enforcement. The bulk of Open vSwitch functionality is platform-agnostic and portable. However the datapath, which touches every packet, is unique to each supported platform. Maintaining each datapath requires duplicated effort and the result has been inconsistent support of features across platforms. Even on a single platform, the features supported by a particular kernel version can vary. Further, datapath functionality must be broadly useful which prevents having application-specific features in the fast path. eBPF, extended Berkeley Packet Filter, enables userspace applications to customize and extend the Linux kernel's functionality. It provides flexible platform abstractions for network functions, and is being ported to a variety of platforms. This paper describes the design, implementation, and evaluation of an eBPF-based extensible OVS datapath. The eBPF OVS datapath delivers the equivalent functionality of the existing OVS kernel datapath, while significantly reducing development pain points around maintainability and extensibility. We demonstrate that these benefits don't necessarily have a trade off in regards to performance, with the eBPFbased datapath showing negligible overhead compared to the existing kernel datapath.

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A distinguishing characteristic of a software-defined network is separation of the network's control plane from its data plane. Especially when the granularity of control is an individual network flow, such separation entails frequent communications between these two planes. This communication pattern demands the same level of resilience from the control plane as that from the data plane, and thus calls into question the conventional out-of-band control network design as used in many existing SDN systems. Peregrine is an Ethernet-based software-defined network that was originally designed as the internal network of a container computer, and unifies storage access, inter-server communication, and network control into a single network comprising only commodity off-the-shelf Ethernet switches. To fully utilize all available physical network links, Peregrine treats the physical network as an explicitly routed mesh and equalizes the loads of its links using a global load-balancing routing algorithm running on a centralized controller. The in-band control architecture of Peregrine leads to two issues: (1) how to evolve a Peregrine network from its initial bootstrapping mode to the explicit routing mode at run time, and (2) how to support fast fail-over for physical failures that break both the control and data plane. This paper describes how Peregrine addresses these two issues, and shows its effectiveness with performance measurements collected from a fully operational test-bed.