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Abstract-In this paper, we introduce a routing solution called "Landmark Overlays for Urban Vehicular Routing Environments" (LOUVRE), an approach that efficiently builds a landmark overlay network on top of an urban topology. We define urban junctions as overlay nodes and create an overlay link if and only if the traffic density of the underlying network guarantees the multi-hop vehicular routing between the two overlay nodes. LOUVRE contains a distributed traffic density estimation scheme which is used to evaluate the existence of an overlay link. Then, efficient routing is performed on the overlay network, guaranteeing a correct delivery of each packet. We evaluate LOUVRE against the benchmark routing protocols of GPSR and GPCR and show that LOUVRE performs higher in packet delivery and achieves lower hop count.

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Abstract-Device driverf ailures have been shown to be a major cause of system failures. Network services stress NIC device drivers, increasing the probability of NIC driverb ugs being manifested as serverf ailures. System virtualization is increasingly used for serverconsolidation and management. The isolated driverdomain (IDD) architectureused by several virtual machine monitors, such as Xen, forms a natural foundation for making systems resilient to NIC driverf ailures. In order to realize this potential, recovery must be fast enough to maintain QoS for network services across NIC driverf ailures. Wes how that the standard Xen configuration, enhanced with simple detection and recovery mechanisms, cannot provide such QoS. However, with NIC drivers isolated in twov irtual machines, in a primary/warm-sparec onfiguration, the system can recoverf rom an overwhelming majority of NIC driverfailures in under 10ms.