arXiv subjects

Mikhail Nesterenko

Publications and source records attributed to Mikhail Nesterenko.

23 records · Page 2Linked to original sources

arXiv2008

Universe Detectors for Sybil Defense in Ad Hoc Wireless Networks

The Sybil attack in unknown port networks such as wireless is not considered tractable. A wireless node is not capable of independently differentiating the universe of real nodes from the universe of arbitrary non-existent fictitious nodes created by the attacker. Similar to failure detectors, we propose to use universe detectors to help nodes determine which universe is real. In this paper, we (i) define several variants of the neighborhood discovery problem under Sybil attack (ii) propose a set of matching universe detectors (iii) demonstrate the necessity of additional topological constraints for the problems to be solvable: node density and communication range; (iv) present SAND -- an algorithm that solves these problems with the help of appropriate universe detectors, this solution demonstrates that the proposed universe detectors are the weakest detectors possible for each problem.

cs.DC↗

arXiv2008

Void Traversal for Guaranteed Delivery in Geometric Routing

Geometric routing algorithms like GFG (GPSR) are lightweight, scalable algorithms that can be used to route in resource-constrained ad hoc wireless networks. However, such algorithms run on planar graphs only. To efficiently construct a planar graph, they require a unit-disk graph. To make the topology unit-disk, the maximum link length in the network has to be selected conservatively. In practical setting this leads to the designs where the node density is rather high. Moreover, the network diameter of a planar subgraph is greater than the original graph, which leads to longer routes. To remedy this problem, we propose a void traversal algorithm that works on arbitrary geometric graphs. We describe how to use this algorithm for geometric routing with guaranteed delivery and compare its performance with GFG.

cs.OS↗

arXiv2008

Snap-Stabilization in Message-Passing Systems

In this paper, we tackle the open problem of snap-stabilization in message-passing systems. Snap-stabilization is a nice approach to design protocols that withstand transient faults. Compared to the well-known self-stabilizing approach, snap-stabilization guarantees that the effect of faults is contained immediately after faults cease to occur. Our contribution is twofold: we show that (1) snap-stabilization is impossible for a wide class of problems if we consider networks with finite yet unbounded channel capacity; (2) snap-stabilization becomes possible in the same setting if we assume bounded-capacity channels. We propose three snap-stabilizing protocols working in fully-connected networks. Our work opens exciting new research perspectives, as it enables the snap-stabilizing paradigm to be implemented in actual networks.

cs.DC↗

arXiv2006

2FACE: Bi-Directional Face Traversal for Efficient Geometric Routing

We propose bi-directional face traversal algorithm $2FACE$ to shorten the path the message takes to reach the destination in geometric routing. Our algorithm combines the practicality of the best single-direction traversal algorithms with the worst case message complexity of $O(|E|)$, where $E$ is the number of network edges. We apply $2FACE$ to a variety of geometric routing algorithms. Our simulation results indicate that bi-directional face traversal decreases the latency of message delivery two to three times compared to single direction face traversal. The thus selected path approaches the shortest possible route. This gain in speed comes with a similar message overhead increase. We describe an algorithm which compensates for this message overhead by recording the preferable face traversal direction. Thus, if a source has several messages to send to the destination, the subsequent messages follow the shortest route. Our simulation results show that with most geometric routing algorithms the message overhead of finding the short route by bi-directional face traversal is compensated within two to four repeat messages.

cs.DC↗

arXiv2006

Discovering Network Topology in the Presence of Byzantine Faults

We study the problem of Byzantine-robust topology discovery in an arbitrary asynchronous network. We formally state the weak and strong versions of the problem. The weak version requires that either each node discovers the topology of the network or at least one node detects the presence of a faulty node. The strong version requires that each node discovers the topology regardless of faults. We focus on non-cryptographic solutions to these problems. We explore their bounds. We prove that the weak topology discovery problem is solvable only if the connectivity of the network exceeds the number of faults in the system. Similarly, we show that the strong version of the problem is solvable only if the network connectivity is more than twice the number of faults. We present solutions to both versions of the problem. The presented algorithms match the established graph connectivity bounds. The algorithms do not require the individual nodes to know either the diameter or the size of the network. The message complexity of both programs is low polynomial with respect to the network size. We describe how our solutions can be extended to add the property of termination, handle topology changes and perform neighborhood discovery.

cs.DC↗