Conference Papers
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506
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Item Path restoration in source routed software defined networks(IEEE Computer Society help@computer.org, 2017) Hegde, S.; Koolagudi, S.G.; Bhattacharya, S.Software defined networks have a central controller and central view of the network, allowing for source routing to be used as a scalable routing technique instead of the traditional destination based forwarding. However, with source routing the switches are reduced to simple forwarding devices, incapable of finding alternate paths in the event of link failures. In this paper we look at techniques to provide resiliency when packets are in transit and a network link failure occurs. Path restoration is one such mechanism wherein we use a bypass path for the failed link. Such bypass paths are stored locally on each of the switches, for all of its outgoing links. This mechanism ensures that the recovery mechanism is scalable since it avoids contacting the controller and takes local corrective measures. We have proposed two approaches for storing the bypass paths. In the first method we store the bypass path between all pairs of nodes. In the second method we store the bypass paths between few selected nodes. These node are the two hop neighbors, chosen using either the two colorable graph approach or the vertex cover approach. Our analysis shows that the second method, using the vertex cover approach reduces the total number of bypass paths stored, without compromising the resiliency. Also our solutions are topology dependent and not path dependent, allowing for most of the computations to be done proactively. © 2017 IEEE.Item Dynamic controller placement in edge-core software defined networks(Institute of Electrical and Electronics Engineers Inc., 2017) Hegde, S.; Ajayghosh, R.; Koolagudi, S.G.; Bhattacharya, S.Software Defined Networking (SDN) is fast gaining acceptance as a networking architecture, which simplifies network management, by separating the control plane from the data plane. Edge-Core SDN is an extended SDN architecture which divides the underlying network into edge and core components. This decouples the edge switch requirements from the network core switch behaviour. When the number of networking elements and traffic flows increase, a single centralized controller can not efficiently manage, the large network nor the diverse requirements of the core and edge switches. We therefore need multiple controllers for wide area SDN deployments. Distributed controller architectures are already recommended to resolve scalability issues. The drawback of these approaches is that they use static mapping of switches to controllers. When the traffic conditions changes this static allotment may lead to unbalanced partitioning of load among the controllers. In this paper, we present controller placement algorithms for SDN, where the edge and core of the network are separated. The algorithm uses a different set of metrics for the edge and core algorithms. Also, in order to establish the Edge-Core model, we use source routing, which embeds the path information into the packet header itself. We also discusses the switch migration procedure for transfer of switch from one controller to another, such that, on going connections are not disrupted. We build a prototype of the above architecture, evaluate it and present our results here. © 2017 IEEE.