Publications (2)0.51 Total impact
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ABSTRACT: In this paper we address the problem of establishing a cost efficient multicast tree among a group of stationary nodes in a multi-hop wireless network. The flooding of broadcast discovery messages is a major limitation to the scalability of most ad hoc protocols. To avoid massive flooding, we limit the reach of broadcast discovery messages, and consider the case were joining nodes can only learn limited information about the multicast group topology from neighbors within a fixed number of hops. We propose two algorithms that satisfy this constraint. We analyze the worst case cost of the established trees and prove that the first algorithm builds a minimal cost spanning tree, while the second builds a sub-optimal tree with a worst-case approximation ratio of O(log n/loglog n). The advantage of the second algorithm is that the communication requirement for a node to join the multicast tree is smaller. We simulate and compare the proposed algorithms. Finally, we discuss the implementation issues and scenarios for using each one of them. We also describe our secure multicast application that builds on top of the proposed protocols.
Conference Paper: Secure multicast groups on ad hoc networks[Show abstract] [Hide abstract]
ABSTRACT: In this paper we address the problem of secure multicast of data streams over a multihop wireless ad hoc network. We propose a dynamic multicast group management protocol that aims at solving problems that are specific to ad hoc networks such as mobility, unreliable links, and cost of multihop communication. The main idea is to have group members actively participate to the security of the multicast group, therefore reducing the communication and computation load on the source. Since the group security is distributed among the group members, we propose a service right certificate, to verify that a node is authorized to join the group, and also a corresponding revocation mechanism. We simulated our protocol within the ns-2 environment under various mobility, group size, and group dynamic scenarios. Our simulation results indicate that the communication cost and join delay of the protocol scale well when the group dynamic and nodes mobility increase. We have implemented the basic protocol in our ad hoc network testbed. We also proposed an extension to the basic secure multicast tree using multi-link capability combined with a k-out-of-N coding approach.
Boston, Massachusetts, United States
- College of Computer and Information Science