Large scale networking has always embraced distributed solutions. Centralized systems elicit knee-jerk reactions, typically pointing to a single-point of failure, difficulty maintaining global state, and operational latency. Nonetheless, centralized solutions have gradually begun to make headway in mainstream networks, such as enterprise networks. In this work, we take this trend one step farther, exploring centralized solutions to two extreme networking environments: Lossy and Low-Power Wireless Networks, and Large-Scale Datacenters.

Low-Power Wireless Networks can be characterized as dynamic high-churn environments with low-bandwidth radios. We present HYDRO, a hybrid routing protocol for low-power wireless networks. At its core, HYDRO forms a directed acyclic graph (DAG) that is locally maintained to support many-to-one collection based routing. In addition, topology reports from individual nodes are gathered to create a "sufficient" global topology view, which subsequently allows for centrally installed state in the network to optimize point-to-point communication.

Within the datacenter context, we focus on the difficulties of incorporating middlebox traversal requirements into the existing architecture. We begin by presenting PLayer, a policy-aware switching layer for datacenters that enables network administrators to explicitly dictate the middlebox traversal sequence of classes of traffic in their network. Given PLayer's predominantly distributed nature, we subsequently present a centralized PLayer design, discussing its ability to handle the demanding scalability requirements of datacenters and provide a comparison of the two designs.




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