Probabilistically Reliable On-Demand Multicast in Wireless Mesh Networks

This paper studies probabilistically reliable multicast in wireless mesh networks (WMNs), utilizing MAC layer retransmission and wireless broadcast advantage to improve both the multicast throughput and the delivery rate. We first present a new multicast routing metric which we call the expected multicast transmissions (EMT). EMT captures the effect of link packet delivery ratio, MAC layer retransmission and wireless broadcast advantage at the same time. The EMT of a MAC layer multicast transmission is the expected number of data transmissions (including retransmissions) required for a packet to reach all the recipients. The EMT of a multicast tree is the sum over the EMT of each forwarding node. Then, we propose a probabilistically reliable on-demand (PROD) multicast protocol with the objective of minimizing the EMT of the multicast tree. Simulation results show that, in comparison with existing approaches, PROD reduces the end-to-end packet loss ratio by up to 30 % and improves the multicast throughput by up to 25%. In addition, it reduces the number of transmissions per packet by up to 40 % and thus significantly reduces the network overhead of the multicast session.

A receiver-initiated soft-state probabilistic multicasting protocol in wireless ad hoc networks

A novel Receiver-Initiated Soft-State Probabilistic multicasting protocol (RISP) for mobile ad hoc network is proposed in this paper. RISP introduces probabilistic forwarding and soft-state for making relay decisions. Multicast members periodically initiate control packets, through which intermediate nodes adjust the forwarding probability. With a probability decay function (soft-state), routes traversed by more control packets are reinforced, while the less utilized paths are gradually relinquished. In this way, RISP can adapt to node mobility: at low mobility, RISP performs similar to a tree-based protocol; at high mobility, it produces a multicast mesh in the network. Simulation results show RISP has lower delivery redundancy than meshbased protocols, while achieving higher delivery ratio. Further, the control overhead is lower than other compared protocols. © 2005 IEEE.published_or_final_versio

A receiver-initiated soft-state probabilistic multicasting protocol in wireless ad hoc networks

A novel Receiver-Initiated Soft-State Probabilistic multicasting protocol (RISP) for mobile ad hoc network is proposed in this paper. RISP introduces probabilistic forwarding and soft-state for making relay decisions. Multicast members periodically initiate control packets, through which intermediate nodes adjust the forwarding probability. With a probability decay function (soft-state), routes traversed by more control packets are reinforced, while the less utilized paths are gradually relinquished. In this way, RISP can adapt to node mobility: at low mobility, RISP performs similar to a tree-based protocol; at high mobility, it produces a multicast mesh in the network. Simulation results show RISP has lower delivery redundancy than meshbased protocols, while achieving higher delivery ratio. Further, the control overhead is lower than other compared protocols. © 2005 IEEE.published_or_final_versio

RODMRP - resilient on demand multicast routing protocol

ODMRP (On-Demand Multicast Routing Protocol) [6] [8] [2] is a popular multicast protocol for wireless ad hoc networks. The strengths of ODMRP are simplicity, high packet delivery ratio, and non-dependency on a specific unicast protocol. ODMRP floods a route request over the entire network to select a set of forwarding nodes for packet delivery. However, a single forwarding path is vulnerable to node failures, which are common due to the dynamic nature of mobile ad hoc networks. Furthermore, a set of misbehaving or malicious nodes can create network partitions and mount Denial-of-Service (DoS) attacks. This thesis proposes a ODMRP-based wireless multicast protocol named RODMRP that offers more reliable forwarding paths in face of node and network failures. A subset of the nodes that are not on forwarding paths rebroadcast received packets to nodes in their neighborhoods to overcome perceived node failures. This rebroadcasting creates redundant forwarding paths to circumvent failed areas in the network. Each node makes this forwarding decision probabilistically. Our simulation results indicate that RODMRP improves packet delivery ratio with minimal overheads, while retaining the original strengths of ODMRP

Reliable Multicast in Mobile Ad Hoc Wireless Networks

A mobile wireless ad hoc network (MANET) consists of a group of mobile nodes communicating wirelessly with no fixed infrastructure. Each node acts as source or receiver, and all play a role in path discovery and packet routing. MANETs are growing in popularity due to multiple usage models, ease of deployment and recent advances in hardware with which to implement them. MANETs are a natural environment for multicasting, or group communication, where one source transmits data packets through the network to multiple receivers. Proposed applications for MANET group communication ranges from personal network apps, impromptu small scale business meetings and gatherings, to conference, academic or sports complex presentations for large crowds reflect the wide range of conditions such a protocol must handle. Other applications such as covert military operations, search and rescue, disaster recovery and emergency response operations reflect the mission critical nature of many ad hoc applications. Reliable data delivery is important for all categories, but vital for this last one. It is a feature that a MANET group communication protocol must provide. Routing protocols for MANETs are challenged with establishing and maintaining data routes through the network in the face of mobility, bandwidth constraints and power limitations. Multicast communication presents additional challenges to protocols. In this dissertation we study reliability in multicast MANET routing protocols. Several on-demand multicast protocols are discussed and their performance compared. Then a new reliability protocol, R-ODMRP is presented that runs on top of ODMRP, a well documented best effort protocol with high reliability. This protocol is evaluated against ODMRP in a standard network simulator, ns-2. Next, reliable multicast MANET protocols are discussed and compared. We then present a second new protocol, Reyes, also a reliable on-demand multicast communication protocol. Reyes is implemented in the ns-2 simulator and compared against the current standards for reliability, flooding and ODMRP. R-ODMRP is used as a comparison point as well. Performance results are comprehensively described for latency, bandwidth and reliable data delivery. The simulations show Reyes to greatly outperform the other protocols in terms of reliability, while also outperforming R-ODMRP in terms of latency and bandwidth overhead

On-Demand Key Distribution for Mobile Ad-Hoc Networks

Mobile ad-hoc networks offer dynamic portable communication with little or no infrastructure. While this has many benefits, there are additional shortcomings specific to wireless communication that must be addressed. This research proposes gossip-based on-demand key distribution as a means to provide data encryption for mobile ad-hoc networks. This technique uses message keys to avoid encrypting and decrypting a message at every node. Other optimizations used include secure channel caching and joint rekey messages. The use of gossip makes the scheme robust to node failure. Experimental results show only a 15% increase in end-to-end delay with a node failure rate of 10%. The percentage of messages successfully delivered to nodes stays between 91-98% under the same 10% node failure rate. The network load is distributed to all nodes in the group preventing overload and single points of failure