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In this paper, we present an energy conservation scheme for wireless ad hoc and sensor networks using gossiping to place nodes in an energy saving sleep state. The technique is termed the Gossip-based Sleep Protocol (GSP). With GSP, each node randomly goes to sleep for some time with gossip sleep probability p. GSP is based on the observation that in a well connected network there are usually many paths between a source and destination, so a percentage of nodes can be in an energy conserving sleep mode without losing network connectivity. GSP needs few operations, scales to large networks and does not require a wireless node to maintain the states of other nodes. We propose two versions of GSP, one for synchronous networks and one for asynchronous networks, and afterward extend GSP to adapt to network traffic conditions. We show the advantages of the GSP approach through both simulations and analysis.

This paper presents the transient performancestudy on the adaptability of an application layer multicastprotocol, namely Adaptive Overlay Multicast (AOM). The studyfocuses on how the application layer multicast tree structure adapts to network dynamics and faults by using efficient tree management and adaptation algorithms, thus reducing the adverse effects of network faults on the application performance. We present extensive simulation studies as well as studies using real Internet data The results show that AOM is highly adaptive to network dynamics while incurring low overhead.

Recently, we have proposed an energy saving Gossip-based Sleep Protocol (GSP) [1] for energy conservation in mobile ad hoc networks. A gossiping node employs a random variable (p) to decide whether or not to enter a sleep mode. Our observation is that in a well connected ad hoc network there are usually many paths existing between a source and a destination, so a percentage (p) of the nodes may be in an energy conserving sleep mode without losing network connectivity. However, putting nodes into a sleep mode may interrupt the ongoing traffic. This can result in a long packet delay and a large packet loss rate. In this paper, we extend GSP to consider the ongoing traffic before changing the radio mode of a node. We term it Traffic-aware GSP (T-GSP) and show its advantages through simulation studies.

In reliable multicast applications, packet loss needs to be reported by having group members send feedback messages. This results in the well-known feedback implosion problem. The available feedback control mechanisms can be classified as timer-based, hierarchy-based and router-assisted, among which the timer-based approach is more preferable due to its simplicity and flexibility. This paper compares the performance of a set of multicast protocols that use either the traditional timer-based feedback control or a combination of the traditional timers and some representatives in the feedback control. We investigate how the use of representatives and deterministic timers improves feedback control performance.

Recently, we have proposed to employ gossiping to place nodes in an ad hoc network in an energy saving sleep state via a gossip-based sleep protocol (GSP). A gossiping node employs a random variable (p) to decide whether or not to enter a sleep mode. Our observation is that in a well connected ad hoc network there are usually many paths existing between a source and a destination, so a percentage (1 - p) of the nodes may be in an energy conserving sleep mode without losing network connectivity. In this paper, we extend the GSP to a non-uniform deployed network, where the node density is not a network-wide constant. The value of p for every node is determined by its local information without incurring much overhead.

This paper proposes a novel energy saving scheme, termed the Gossip-based sleep protocol (GSP). With GSP, each node randomly goes to sleep for some time with gossip sleep probability p. When the value of p is small enough, the network stays connected. GSP does not require a wireless node to maintain the states of other nodes. It requires few operations and scales to large networks. Two versions of GSP, one for synchronous networks and one for asynchronous networks are proposed, and the advantages of the GSP approach through both simulations and analysis is showed in this paper.

In this paper, the adaptive overlay multicast (AOM) protocol is presented, which is specially beneficial to long-lasting, large data distribution applications with large receiver sets. AOM distinguishes itself from the previous research with the following characteristics: (1) scalable overlay multicast tree construction method and a scoping technique to decrease overhead, (2) active adaptation to dynamic network conditions, and (3) efficient loss measurement and adaptation algorithms. We present extensive simulations of AOM including real Internet data and compare it with a HMTP-like protocol. The results show that AOM builds high-quality trees and adapts well to the network conditions while incurring low overhead.