Abstract-Software Defined Networks (SDN) decouple the forwarding and control planes from each other. The control plane is assumed to have a global knowledge of the underlying physical and/or logical network topology so that it can monitor, abstract and control the forwarding plane. In our paper, we present solutions that install an optimal or near-optimal (i.e., within 14% of the optimal) number of static forwarding rules on switches/routers so that any controller can verify the topology connectivity and detect/locate link failures at data plane speeds without relying on state updates from other controllers. Our upper bounds on performance indicate that sub-second link failure localization is possible even at data-center scale networks. For networks with hundreds or few thousand links, tens of milliseconds of latency is achievable.

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Due to copyright restrictions, the access to the full text of this article is only available via subscription.In current Internet, the most significant and the growing promotion rate of the network resources usage is due to the Peer to Peer(P2P) applications. These studies show us that the main traffic type, that Internet Service Providers (ISPs) should route, is P2P traffics. Since P2P overlay network model is networkoblivious, due to its nature, it causes inefficient network utilization, and low quality of experiences, from the perspective of the network providers and the end users respectively. Therefore, this unnecessary resource utilization increases inter-ISP traffic, and lead to serious disruption on ISPs economics. In this paper, we will implement a BitTorrent-Like simulator and Application Layer Traffic Optimization (ALTO) Server, in order to analyze and improve the performance of the overall system, by using a novel peer selection algorithms. Our results show that using this type of P2P overlay, reduces the Data Download Completion Time about and Inter-ISP Link Utilization about 50%.Türk Telekomünikasyon A. Ş

We present efficient solutions that install static rules on the forwarding elements such that network controllers use these rules to verify topology connectivity and locate link failures. For a forwarding plane with |E| links, we verify topology connectivity using ≤ 2|E| static rules and one control message. We guarantee locating at least one link failure using ≤ 6|E| static rules and Θ(log(|E|)) control messages. We can also detect multiple link failures in a probabilistic sense.