A Node Virtualization Scheme for Structured Overlay Networks Based on Multiple Different Time Intervals

Sensor data which relate to the specific geographical positions, areas, and time are strongly expected in IoT. The author has studied overlay networks to efficiently process interval queries which have specific time intervals and the actual users tend to request. However, unfairness and a concentration of the loads occur for the specific processing computer (node) in the previous method because the density of data or those generators/providers is different from those related values. In this paper, the author proposes the enhanced scheme for structured overlay networks based on multiple different time intervals. The proposed method uses node virtualization to equalize the loads of each real (physical) node. The simulation results showed that the proposed method can increase the fairness of the number of the assigned data among physical nodes.

Resilient Tree-Based Video Streaming with a Guaranteed Latency

In this paper, we propose a method to organize a tree-based Peer-to-Peer (P2P) overlay for video streaming which is resilient to the temporal reduction of the upload capacity of a node. The basic idea of the proposed method is: (1) to introduce the redundancy to a given tree-structured overlay, in such a way that a part of the upload capacity of each node is proactively used for connecting to a sibling node, and (2) to use those links connecting to the siblings to forward video stream to the siblings. More specifically, we prove that even if the maximum number of children of a node temporally reduces from m to m − k for some 1 ≤ k ≤ m − 1, the proposed method continues the forwarding of video stream to all of m children in at most 2x hops, where x is the smallest integer satisfying m − k ≥ m/2x. We also derive a sufficient condition to bound the increase of the latency by an additive constant. The derived sufficient condition indicates that if each node can have at least six children in the overlay, the proposed method increases the latency by at most one, provided that the number of nodes in the overlay is at most 9331; namely the proposed method guarantees the delivery of video stream with a nearly optimal latency.

Routing performance of structured overlay in Distributed Hash Tables (DHT) for P2P

This paper presents a routing performance analysis of structured P2P overlay network. Due to the rapid development and hectic life, sharing data wirelessly is essential. P2P allows participating peers move freely by joining and leaving the network at any convenience time. Therefore, it exists constraint when one measuring the network performance. Moreover, the design of structured overlay networks is fragmented and with various design. P2P networks need to have a reliable routing protocol. In order to analyse the routing performance, this work simulates three structured overlay protocols-Chord, Pastry and Kademlia using OMNeT++ with INET and OverSim module. The result shows that Pastry is the best among others with 100% routing efficiency. However, Kademlia leads with 12.76% and 18.78% better than Chord and Pastry in lookup hop count and lookup success latency respectively. Hence, Pastry and Kamelia architectures will have a better choice for implementing structured overlay P2P network.