Raghuvel S. Bhuvaneswaran

Fundamental protocols for wireless sensor networks

The main contribution of this work is to present energyefficient protocols that compute the sum of n numbers over any commutative and associative binary operator stored in n wireless sensor nodes arranged in a two-dimensional grid of size √ n × √ n. We first present a protocol that computes the sum in O(r 2 +( n r2) 1 3) time slots with no sensor node being awake for more than O(1) time slots, where r is the transmission range of the sensor nodes. We then show a fault-tolerant protocol that computes the sum in the same number of time slots with no sensor node being awake for more than O(log r) time slots.

Dynamic Co-allocation Scheme for Parallel Data Transfer in Grid Environment

The large sized data sets are replicated in more than one site for the better availability to the nodes in a grid. Downloading the dataset from these replicated locations have practical difficulties, due to network traffic, congestion, frequent change-in performance of the servers, etc. In order to speed up the download, complex server selection techniques, network and server loads are used. However, consistent performance is not guaranteed due to the shared nature of network links of the load on them, which can vary unpredictably. Hence, we find interest in a co-allocated download model, which enables parallel download of replicated data from multiple servers. In this paper, we proposed a dynamic co-allocation scheme for parallel data transfer in grid environment, which copes up with highly inconsistent network performances of the servers. We have developed an algorithm using circular queue, with which, the data transfer tasks are allocated onto the servers in duplication. Our scheme is highly fault tolerant one, in other words, the process of data transfer will neither be interrupted nor paralyzed, even when the link to servers under consideration is broken or idleness of the servers, whereas, none of the existing mechanisms consider the situation. We used Globus toolkit for our framework and utilized the partial copy feature of GridFTP. We compared our scheme with the existing schemes and the preliminary results show notable improvement in overall completion time of data transfer.

A multipath on-demand routing with path selection probabilities for mobile ad hoc networks

This paper proposes a novel on-demand multipath routing protocol (AODVM-PSP) for a mobile ad hoc network. We devised a new multipath utilization method with probability selection, with which each node deliberately selects one of the multipath routes to utilize. We examined our protocol under various network loads. We evaluated our protocol with Omnet simulator and the performance is compared with conventional methods. When the network load is high, the number of the routing control packets is prodigious. The simulation results show that our proposed protocol has significant improvement over others in high load.

A Framework for an Integrated Co-allocator for Data Grid in Multi-Sender Environment

Data grid consists of scattered computing and storage resources located dispersedly in the grid network. These large sized data sets are replicated in more than one site for the better availability to the other nodes in a grid. Downloading the dataset from these replicated locations have practical difficulties and we find interest in a co-allocated download framework, which enables parallel download of replicated data from multiple servers. In this paper, we proposed a dynamic co-allocation scheme for parallel data transfer in grid environment, which copes up with highly inconsistent network and server performance. The model comprises of co-allocator, monitor and control mechanisms. The scheme initially obtains the bandwidth parameter from the monitor module to fix the partition size and the data transfer tasks are allocated onto the servers in duplication. In this way, the process of data transfer can neither be interrupted nor paralyzed, even when the network link is broken or server crash. We used Globus toolkit for our framework by making use of grid information and GridFTP services. We compared our scheme with the existing schemes and the results show notable improvement in overall completion time of data transfer.

On-demand multipath routing protocol with preferential path selection probabilities for MANET

We developed an ad hoc on-demand multipath distance vector protocol with path preferential selection probabilities (AODVM-PPSP) for a mobile ad hoc network (MANET). This protocol introduces a new method, in which each node deliberately selects one of the multipath routes to utilize. It adapts preference for the route with the least transmission delay time and node throughput. We examined our protocol under various network loads. We evaluated our protocol with Omnet simulator and the performance is compared with the conventional methods. We found that the multiple routes were efficiently selected and there by resulted in higher packet delivery ratio and lower routing packets. The simulation results show that our proposed protocol has the significant improvement over others.

Implementation of packet filter configurations anomaly detection system with SIERRA

Packet filtering in a firewall is one of the useful tools for network security. Packet filtering examines network packet and decides whether to accept, or deny it and this decision is determined by a packet filtering configuration developed by the network administrator. An administrator may find hard to understand and maintain a configuration, and this burden will furthermore be increased to find anomalies between two configurations, especially when the size of filters in a configuration increased. This difficulty may leave the administrator with less confidence that the configurations are correctly and completely implemented. This paper presents a system with SIERRA (A systolic filter sieve array) which can detect the anomalies between two configurations. It provides three functions, side-effects analysis function, equality judgment function, and composition analysis function. Experimental results show that the proposed system is suitable for small network and configurations with large number of filters.

Analysis Methods of Firewall Policies by using Spatial Relationships between Filters

Network security can be increased by filtering packets at a firewall. Packet filtering examines network packets and decides whether to accept or deny them, and these decisions are made according to policies that are established by the network administrator and implemented by specific filters. An administrator who finds it hard to understand and maintain a policy, will not easily find problems that occur when the filters are changed (added, deleted, or replaced) or when hierarchical firewalls are used and will therefore not be certain that the intended policies are implemented correctly and completely. In this paper, we consider the relations of filters as spatial relations, and propose three analysis methods (impact inferring, equality judgment, and composition analysis) to determine anomalies of firewall policies by using spatial relations between filters

Inferring the Impact of Firewall Policy Changes by Analyzing Spatial Relations between Packet Filters

Network security can be increased filtering packets at a firewall. Packet filtering examines network packets and decides whether to accept or deny them, and these decisions are made according to policies that are established by the network administrator and implemented by specific filters. An administrator who finds it hard to understand and maintain a policy, will not easily find problems that occur when the filters are changed (added, deleted, or replaced) and will therefore not be certain that the intended policies are implemented correctly and completely. In this paper, we consider the relations between filters as spatial relations, and show how the impact of firewall policy changes can be determined by analyzing spatial relations between filters. Using these relations reduces the amount of computation required for impact analysis because it eliminates the need to compare all the predicates involved in the filters. Experimental results show that the proposed impact analysis method is suitable for small networks and can be used for policies with large numbers of filters.

Dynamic Route Selection Policy Protocol in MANET

Multipath route selection policy has been studied in the context of mobile ad hoc networks (MANET). According to the utilization of multiple routes these selection policies have been categorized into two parts: best routing policy and load balancing policy. Many ad hoc routing protocols are based on best routing policy, such as the fastest or the shortest routing policy with local traffic optimization. However, the lack of global perspective might increase congestion resulting in damage of the local traffic. On the other hand, load balancing policy protocols try to avoid traffic congestion by equalizing traffic load of the multipath. But these load balancing policy protocols lost many traffic chances and cause low traffic performance on special condition. In this paper, we illustrate the adverse impact of these two types of route selection policy protocols on mobile ad hoc network and propose a new routing protocol, which switches the route selection policy with consideration of the dynamic network condition. Our protocol is evaluated with Omnet simulator. The simulation results show that the proposed scheme offers a high packet delivery ratio and low packet overhead ratio than other protocols.

AODV-based multipath routing protocol with preferential path selection probabilities

We develop an AODV (Ad hoc On-demand Distance Vector)-based Multipath routing protocol with Preferential Path Selection Probabilities (AODVM-PPSP) for a Mobile Ad hoc Network (MANET). This protocol introduces a new method, in which an appropriate policy is decided deliberately between the best selection policy and the moderate load balancing policy, providing corresponding preferential path selection probabilities (P i) to each node for selecting a route among the multipath. The best selection policy uses one route and saves backup routes information for fault tolerance. The moderate load balancing policy uses route diversity to balance network load. So the path selection policy is adapted with consideration of the global dynamic network performance. We evaluate our protocol with Omnet simulator and compare the performance with some conventional methods under various network loads. The simulation results show that our proposed protocol has a significant improvement over the others.