Mobile agents aided multicast routing in mobile ad hoc networks

Due to its simplicity, efficiency, and robustness to mobility, the On-Demand Multicast Routing Protocol (ODMRP) becomes a standout amongst the most broadly utilized multicast routing protocols in mobile ad hoc networks (MANETs). However, the robustness of ODMRP comes at the expense of incurring a high control overhead to the network. The Enhanced ODMRP (EODMRP) proposed a dynamic refresh interval for the multicast mesh based on the network feedback on real disconnections experienced by the multicast network members. Veritably, EODMRP decreased the network control overhead at the cost of obtaining a low packet delivery ratio especially in high mobility conditions of the network. In this paper, two protocols, as improvements to both ODMRP and EODMRP, are proposed where the refresh interval is basically adapted based on the source moving speed and the number of disconnections reported by multicast members. Furthermore, we proposed an impressive local recovery to be employed in both protocols, which includes new setup and failure mechanisms that contribute effectively to boosting the performance of our proposed protocols. Since the majority of nodes in MANET rely on batteries, the main contribution of this research is to limit the amount of control information that is passed between nodes (i.e., reducing the control overhead over that in ODMRP) while maintaining a better packet delivery ratio than EODMRP.

Ad hoc wireless networks are self-organizing dynamic topology networks formed by a collection of mobile nodes through radio links. Minimal configuration absence of infrastructure and quick deployment make them convenient for emergency situations other than military applications. Multicasting plays a very crucial role in the application of Ad hoc networks. As the number of participants increases scalability of the multicast protocol becomes an important issue. Among the existing multicast protocols On Demand Multicast Routing Protocol (ODMRP) perfo exhibits a high packet delivery ratio even at high mobility. But ODMRP suffers from higher control overhead as the network size and the number of sources increase.In this paper we propose an efficient multicast routing protocol for Ad hoc wireless networks. This protocol reduces the control overhead by dynamically classifying the sources into Active and Passive categories. The control overhead is significantly reduced by about 30% compared to ODMRP which contributes to the scalability of the protocol. We study the effectiveness of the proposed multicast routing protocol by simulation studies and the results show that the multicast efficiency is increased by 10--15% and packet delivery ratio is also improved at high network load.

The multicast routing protocols used in wire network, such as distance vector multicast routing protocol(DVMRP), multicast open shortest path first(MOSPF), core based tree(CBT), do not run very well in ad hoc network because the dynamic net topology may destroy the distribution tree. Besides, distribution tree usually needs global routing structure. Which produces extra processing cost because the dynamic topology will introduce frequent exchange of routing vector or routing state between nodes. To deal with these problems multicast forwarding group routing protocol (MFGRP) which is based on route grid is designed on basis of dynamic source routing protocol (DSR). MFGRP ensures the multicast packets are sent to destination through dynamic topology network using multicast route grid.

Recently, the study of multicast routing attracts more attentions in MANET. Multicast Ad Hoc On-Demand Distance Vector (MAODV) protocol, which is multicast operation of the Ad hoc On-Demand Distance Vector (AODV) routing protocol, enables dynamic, self-starting, multihop routing between participating mobile nodes wishing to join or participate in a multicast group within an Ad Hoc network. Through analyzing its operation mechanism, we present a probability based multicast routing protocol with energy constrained (PBMR),in which a hybrid probability forwarding strategy is adopted. When a node wants to join a multicast tree, it floods a RREQ-Join message to its neighbors, when the neighbors receive this message, the neighbor with much energy left has a high probability to forward the message, and so on. By making correctness proof and complexity analysis of PBMR, this paper evaluates MAODV and PBMR with extensive simulations, the results show that PBMR has a better jitter than MAODV and a more balance in energy consumption. On the one hand, it saves the energy of the network system; on the other hand, it has a longer network lifetime and a more stable routing than MAODV and successfully solves the inconsistent problem of energy and scalability.

Multicast routing in mobile ad hoc networks by using a multiagent system

On demand multicast routing protocol (ODMRP) is a typical mesh-based multicast routing protocol for mobile ad hoc network, but its poor scalability limits its application in large scale network. This paper presents a timer forecasting zone based on demand multicast routing protocol (TFZMP) for mobile ad hoc network (MANET). In TFZMP, the network is divided into zones based on timer forecasting mechanism. Mesh structures inside each zone provide good adaptability to network topology changes. Zone division based on timer forecasting mechanism decreases the data overhead of multicast routing and enhances the scalability of the network. The proposed TFZMP protocol is simulated and compared with ODMRP on OPNET. Simulation results show that TFZMP performs better than ODMRP on the aspects of normalized overhead and packet forwarding efficiency at any mobility model.

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Efficient multicasting over Wireless Mesh Network (WMN) is challenging due to dynamic and multi-hop wireless communication among multicast group members. Multicast Ad hoc On-Demand Distance Vector (MAODV) protocol is a tree based multicast routing protocol that enables dynamic, self-starting, multi-hop routing between participating mobile nodes wishing to join or participate in a multicast group in Wireless Mesh Network (WMN). The mobility of mobile nodes often causes link breakage in the tree-based protocols which sometime results in tree partitioning and poor performance. In MAODV, when a broken link is detected between two nodes on the multicast tree, the node downstream to the break is responsible for initiating the repair of the broken link. After link repair, it is likely that the previous distance between the nodes (nodes downstream to the link breakage) and the group leader will not remain same. The shortest path from the group leader to the nodes downstream to the node which initiates link breakage is not ensured. Moreover, if the node attempting to repair a tree link break does not receive a response after certain attempts, it assumes that the multicast tree is not repairable currently and this leads to tree partitioning. In this paper, an improved link repair technique is proposed which ensures shortest path from any node to the group leader. Simulation results demonstrate significant improvement in performance metrics compared to standard MAODV.

In this paper, we investigate two new hybrid protocols obtained by combination of proactive and reactive behaviors of other two well-known multicast routing protocols, namely the ODMRP and the MAODY. Hybrid routing protocols are known to perfonn better then either pure reactive or proactive protocols in the sense that they 1Iy to strike a balance between improved delay perfonnance and lower ovemead activities. In this work we combine the zone routing proactive behavior of the ZRP protocol with the reactive behavior of the ODMRP and MAODV protocols. The new protocols are named ZMAODV and WDMRP. Using Glomosim simulation we evaluate the perfonnance of these protocols and compare them to their original counte1parts as well as to the Multicast Zone Routing Protocol (MZR). The results reveal that the ZODMRP perfonns the best while the MZR exhibits the worst perfonnance.

The high-level contribution of this paper is the design and development of routing protocols to discover stable paths and trees for unicast and multicast communication based on the predicted link expiration times LETs of links in mobile ad hoc networks MANETs. Both of the stability-based unicast SILET and multicast MILET routing protocols discover routes through an on-demand request-reply cycle with a link weight being 1 plus the inverse of the LET of the link. The destination nodes and the multicast receiver nodes connect to the source node through paths that have the lowest sum of the link weights. The inclusion of a '1' in the link weight helps to minimise the hop count of the paths from the source node to each of the targeted end nodes of the communication session; the inclusion of the inverse of the LET in the path/tree optimisation function helps to maximise the path/tree lifetime. The proposed protocols effectively neutralise the stability-hop count tradeoff and are able to simultaneously maximise the path/tree lifetime and minimise the hop count per source-destination/source-receiver path. The performance of SILET and MILET has been extensively studied in the ns-2 simulator along with contemporary unicast and multicast routing protocols.

In this paper, an intellectual energy efficient multicast routing protocol is proposed. It achieves enhanced performance over On-Demand Multicast Routing Protocol (ODMRP). The proposed protocol finds energy efficient multicast routes from source node to a group of receivers. Multicast mesh creation involves two phases: a Join Query (J-Q) phase and a Join Reply (J-R) phase. The J-Q phase initiates a route discovery process to find routes of the multicast group. In J-R phase, different routes of the multicast groups are set up. In the proposed protocol, we modify ODMRP and introduce fuzzy inference system to deal with imprecise and partial information during the route discovery phase. The decision maker uses two fuzzy variables such as energy and distance for evaluating reward as an output parameter of each multicast route. This output parameter helps to distinguish different multicast route and it also helps to reduce the effect of mutual interference between routes. The proposed protocol is simulated using the NS-2 simulator. The performance of the proposed protocol is compared with existing multicast routing protocols, and results outperform existing protocols in terms of several network metrics.

In MANETs, there are many critical issues such as energy consumption, QoS, exposure to attacks, link stability etc. that need to be addressed for improved communication. `Link Stability' is important because radio links are likely to be unreliable due to node mobility. This instability leads to increased rerouting which further escalates routing overhead. One way of reducing routing overhead is use of multicasting instead of unicast routing. Multicast Routing Protocol transmits data simultaneously to a group of destination nodes to achieve better resource utilization. In this paper, we present a multicasting routing protocol that uses received signal strength as a metric to estimate link stability. Estimated SINR (Signal to Interference plus Noise Ratio) at every node in respect of different senders is used to determine a reliable path that is likely to mitigate link failures and reduce end-to-end delay. For any two nodes, we aim at finding best link with high probability of longer lifetime. We have simulated our experiment on Exata/Cyber Simulator and compared the result of the proposed routing protocol with ODMRP (On-Demand Multicast Routing Protocol) based on minimum hop count. Analysis of our simulation results show improvement of various routing performance metrics such as PDR, Routing Overhead and packet drop ratio.

Performance evaluation of a mesh-evolving quality-of-service-aware multicast routing protocol for mobile ad hoc networks

On-Demand Multicast Routing Protocol (ODMRP) is a well-known protocol for ad hoc networks. This protocol is mesh based and exhibits a high packet delivery ratio even at high mobility. In ODMRP the robustness is achieved by using the number of multiple routes which is a solution for the high speed mobility and the subsequent route breaking. The ODMRP is such designed that the number of multiple routes only depends on the number of senders and receivers, irrespective of the node speed and the traffic load. In this paper we proposed a Reduced Data Transmission ODMRP (RDTODMRP) routing algorithm that considers the network conditions e.g. mobility speed and traffic load to determine the multiple routs. This cuts down the unnecessary redundant routes and their data transmissions. Furthermore in ODMRP and RDTODMRP, flooding of Join-Request packets causes excessive control overhead, In order to solve the problem, we Limit some nodes to Flood Join-Request packets and forbid it to be a forwarding node (LF-RDTODMRP). It is shown by simulation that the RDTODMRP and LF-RDTODMRP reduce the number of data transmission, control overhead, end to end delay and improve the data packet delivery ratio.

Ad Hoc Routing with Distributed Ordered Sequences