BGP-like TE Capabilities for SHIM6

In this paper we present a comprehensive set of mechanisms that restore to the site administrator the capacity of enforcing traffic engineering (TE) policies in a multiaddressed IPv6 scenario. The mechanisms rely on the ability of SHIM6 to securely perform locator changes in a transparent fashion to transport and application layers. Once an outgoing path has been selected for a communication by proper routing configuration in the site, the source prefix of SHIM6 data packets is rewritten by the site routers to avoid packet discarding due to ingress filtering. The SHIM6 locator preferences exchanged in the context establishment phase are modified by the site routers to influence in the path used for receiving traffic. Scalable deployment is ensured by the stateless nature of these mechanisms.Publicad

Practical effects in the preparation of cluster states using weak non-linearities

We discuss experimental effects in the implementation of a recent scheme for performing bus mediated entangling operations between qubits. Here a bus mode, a strong coherent state, successively undergoes weak Kerr-type non-linear interactions with qubits. A quadrature measurement on the bus then projects the qubits into an entangled state. This approach has the benefit that entangling gates are non-destructive, may be performed non-locally, and there is no need for efficient single photon detection. In this paper we examine practical issues affecting its experimental implementation. In particular, we analyze the effects of post-selection errors, qubit loss, bus loss, mismatched coupling rates and mode-mismatch. We derive error models for these effects and relate them to realistic fault-tolerant thresholds, providing insight into realistic experimental requirements.Comment: 8 pages, 5 figure

Randomized benchmarking of single and multi-qubit control in liquid-state NMR quantum information processing

Being able to quantify the level of coherent control in a proposed device implementing a quantum information processor (QIP) is an important task for both comparing different devices and assessing a device's prospects with regards to achieving fault-tolerant quantum control. We implement in a liquid-state nuclear magnetic resonance QIP the randomized benchmarking protocol presented by Knill et al (PRA 77: 012307 (2008)). We report an error per randomized $\frac{\pi}{2}$ pulse of $1.3 \pm 0.1 \times 10^{-4}$ with a single qubit QIP and show an experimentally relevant error model where the randomized benchmarking gives a signature fidelity decay which is not possible to interpret as a single error per gate. We explore and experimentally investigate multi-qubit extensions of this protocol and report an average error rate for one and two qubit gates of $4.7 \pm 0.3 \times 10^{-3}$ for a three qubit QIP. We estimate that these error rates are still not decoherence limited and thus can be improved with modifications to the control hardware and software.Comment: 10 pages, 6 figures, submitted versio

IPv6 Multihoming Support in the Mobile Internet

Fourth-generation mobile devices incorporate multiple interfaces with diverse access technologies. The current Mobile IPv6 protocol fails to support the enhanced fault tolerance capabilities that are enabled by the availability of multiple interfaces. In particular, established MIPv6 communications cannot be preserved through outages affecting the home address. In this article, we describe an architecture for IPv6 mobile host multihoming that enables transport layer survivability through multiple failure modes. The proposed approach relies on the cooperation between the MIPv6 and the SHIM6 protocols.Publicad

Fault Tolerant Scalable Support for Network Portability and Traffic Engineering

The P-SHIM6 architecture provides ISP independence to IPv6 sites without compromising scalability. This architecture is based on a middle-box, the P-SHIM6, which manages the SHIM6 protocol exchange on behalf of the nodes of a site, which are configured with provider independent addresses. Incoming and outgoing packets are processed by the P-SHIM6 box, which can assign different locators to a given communication, either when it is started, or dynamically after the communication has been established. As a consequence, changes required for provider portability are minimized, and fine-grained Traffic Engineering can be enforced at the P-SHIM6 box, in addition to the fault tolerance support provided by SHIM6.This project has been supported by the RiNG project IST-2005-035167 and by the IMPROVISA project TSI2005-07384-C03-02.Publicad

Identifying Design Requirements for Wireless Routing Link Metrics

In this paper, we identify and analyze the requirements to design a new routing link metric for wireless multihop networks. Considering these requirements, when a link metric is proposed, then both the design and implementation of the link metric with a routing protocol become easy. Secondly, the underlying network issues can easily be tackled. Thirdly, an appreciable performance of the network is guaranteed. Along with the existing implementation of three link metrics Expected Transmission Count (ETX), Minimum Delay (MD), and Minimum Loss (ML), we implement inverse ETX; invETX with Optimized Link State Routing (OLSR) using NS-2.34. The simulation results show that how the computational burden of a metric degrades the performance of the respective protocol and how a metric has to trade-off between different performance parameters

Oscillation-Based Test Structure and Method for OTA-C Filters

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”This paper describes a design for testability technique for operational transconductance amplifier and capacitor filters using an oscillation-based test topology. The oscillation-based test structure is a vectorless output test strategy easily extendable to built-in self-test. The proposed methodology converts filter under test into a quadrature oscillator using very simple techniques and measures the output frequency. The oscillation frequency may be considered as a digital signal and it can be evaluated using digital circuitry therefore the test time is very small. These characteristics imply that the proposed method is very suitable for catastrophic and parametric faults testing and also effective in detecting single and multiple faults. The validity of the proposed method has been verified using comparison between faulty and fault-free simulation results of two integrator loop and Tow-Thomas filters. Simulation results in 0.25 mum CMOS technology show that the proposed oscillation-based test strategy for OTA-C filters has 87% fault coverage and with a minimum number of extra components, requires a negligible area overhead