Urmila Bhanja

FWM aware evolutionary programming algorithm for transparent optical networks

This paper proposes and evaluates a four-wave mixing (FWM) aware evolutionary programming algorithm for dynamically setting up lightpaths in an optical wavelength division multiplexed network (WDM network). The proposed algorithm also considers the effect of amplified spontaneous emission noise (ASE noise) on a lightpath during propagation of the optical signal from any source to the intended destination. As crosstalk due to FWM and ASE noise are two transmission impairments that degrade the quality of optical signal even at low to medium data rates, it is mandatory for an algorithm for dynamic routing and wavelength assignment in a WDM network to consider the effect of these two impairments on the lightpath to be established. The distinguishing feature of the proposed algorithm is that it is based on an initial population of a single individual and uses a fitness function that is expressed in terms of the number of hops, path cost, variance contributions due to FWM crosstalk, amplifier noise, and different beat noises at the receiver. The performance of a newly introduced FWM aware priority-based wavelength assignment technique is compared with few of the existing wavelength assignment techniques in the present work.

An evolutionary programming algorithm for survivable routing and wavelength assignment in transparent optical networks

The dynamic routing and wavelength assignment (DRWA) problem is a challenging optimisation problem in optical wavelength division multiplexed (WDM) networks. This paper proposes a novel evolutionary programming algorithm, namely, ERWA, to reduce the set-up time of lightpaths in a WDM network. It is shown that the proposed algorithm with simple extensions, referred to in this paper as ESRWA, is able to provide dedicated protection at the optical layer of the network, thereby addressing the survivable DRWA problem. In contrast to other bio-inspired algorithms available in the literature for the DRWA problem, ERWA facilitates the online discovery of a requested lightpath. The novelty of ERWA lies in the fact that it uses an initial population consisting of only one individual or chromosome and integrates a soft constraint with a set of hard constraints to accomplish proper load balancing. These features result in a lower mean blocking probability and a lower mean execution time compared to those exhibited by the existing bio-inspired algorithms for both the DRWA and the survivable DRWA problems.

An evolutionary programming algorithm for finding constrained optimal disjoint paths for multihop communication networks

We present an evolutionary programming algorithm (EP) for finding hop count and bandwidth constrained cost optimal disjoint paths in multihop communication networks. In general, multi-constrained path selection is an NP complete problem. Our proposed algorithm can be used for real-time online network applications, which can initiate and process a number of calls simultaneously on disjoint paths, without overloading the network. This algorithm also requires a small memory space and low execution time. The proposed algorithm, which maintains a balance between finding an optimal shortest path and CPU mean execution time, also generates parallel suboptimal paths during the process of generating the best path. One of these suboptimal paths can be used as a backup path if it is link disjoint with all the primary paths (best paths) of the concurrent requests. Thus, the proposed algorithm provides a limited degree of reliability for routing of packets as well.

A metaheuristic approach for optical network optimization problems

Two of the most complex optimization problems encountered in the design of third generation optical networks are the dynamic routing and wavelength assignment (DRWA) problem under the assumptions of ideal and non-ideal physical layers. Both these problems are NP-complete in nature. These are challenging due to the presence of multiple local optima in the search space. Even heuristics-based algorithms fail to solve these problems efficiently as the search space is non-convex. This paper reports the performance of a metaheuristic, that is, an evolutionary programming algorithm in solving different optical network optimization problems. The primary motivation behind adopting this approach is to reduce the algorithm execution time. It is demonstrated that the same basic approach can be used to solve different optimization problems by designing problem-specific fitness functions. Also, it is shown how the algorithm performance can be improved by integrating suitable soft constraints with the original constraints. Exhaustive simulation studies are carried out assuming the presence of different levels of linear impairments such as switch and demultiplexer crosstalk and non-linear impairments like four wave mixing to illustrate the superiority of the proposed algorithms.

SecNRCC: a loss-tolerant secure network reprogramming with confidentiality consideration for wireless sensor networks

Network reprogramming faces lots of threats from both external attackers and potentially compromised nodes. Security thus becomes a critical requirement for network reprogramming protocols. This paper describes a secure network reprogramming system called SecNRCC for dynamically reprogramable wireless sensor network. In SecNRCC, a light weight authentication method is firstly introduced for the reboot control command. Secondly, a program image preprocess method with security and loss‐tolerance consideration is proposed. Furthermore, a novel immediate packet authentication algorithm with confidentiality consideration is also presented to resist the denial of service attacks exploiting the authentication delay, and finally, a weak authentication operation is performed before the digital signature verification to mitigate denial of service attacks against signature packets. The experimental results show that SecNRCC can securely disseminate the program image to all of node in the wireless sensor networks with acceptable latency and message cost. Copyright

LDSCD: A loss and DoS resistant secure code dissemination algorithm supporting multiple authorized tenants

Abstract Code dissemination protocol faces lots of threats from both the external and potentially internal attackers. Security thus becomes a critical requirement for code dissemination protocols in the wireless sensor networks (WSNs). This paper proposes a loss and denial of service (DoS) resistant secure code dissemination algorithm that supports multiple authorized tenants, referred in this work as a loss and DoS resistant secure code dissemination (LDSCD) for WSNs. In LDSCD, a social role-based distributed online code dissemination framework is proposed. In the proposed framework, the owner of WSNs is not directly involved in the code dissemination and a conditional proxy re-signature technique is utilized to authorize different tenants. The algorithm also proposes a detailed conditional proxy re-signature scheme for the online code dissemination with a security proof. Furthermore, a novel immediate packet authentication algorithm with loss-resilient consideration is also presented in this work to resist the DoS attacks exploiting the authentication delay. The experimental results show that the proposed LDSCD securely disseminates the Program Image to all nodes in the WSNs with acceptable latency and message cost. Furthermore, the experimental results also demonstrate that the proposed LDSCD outperforms the existing code dissemination algorithms in terms of dissemination cost and latency.

A Novel Solution to the Dynamic Routing and Wavelength Assignment Problem in Transparent Optical Networks

We present an evolutionary programming algorithm for solving the dynamic routing and wavelength assignment (DRWA) problem in optical wavelength-division multiplexing (WDM) networks under wavelength continuity constraint. We assume an ideal physical channel and therefore neglect the blocking of connection requests due to the physical impairments. The problem formulation includes suitable constraints that enable the algorithm to balance the load among the individuals and thus results in a lower blocking probability and lower mean execution time than the existing bio-inspired algorithms available in the literature for the DRWA problems. Three types of wavelength assignment techniques, such as First fit, Random, and Round Robin wavelength assignment techniques have been investigated here. The ability to guarantee both low blocking probability without any wavelength converters and small delay makes the improved algorithm very attractive for current optical switching networks.

Comparison of novel coding techniques for a fixed wavelength hopping SAC-OCDMA

The optical code division multiple access (OCDMA), the most advanced multiple access technology in optical communication has become significant and gaining popularity because of its asynchronous access capability, faster speed, efficiency, security and unlimited bandwidth. Many codes are developed in spectral amplitude coding optical code division multiple access (SAC-OCDMA) with zero or minimum cross-correlation properties to reduce the multiple access interference (MAI) and Phase Induced Intensity Noise (PIIN). This paper compares two novel SAC-OCDMA codes in terms of their performances such as bit error rate (BER), number of active users that is accommodated with minimum cross-correlation property, high data rate that is achievable and the minimum power that the OCDMA system supports to achieve a minimum BER value. One of the proposed novel codes referred in this work as modified random diagonal code (MRDC) possesses cross-correlation between zero to one and the second novel code referred in this work as modified new zero cross-correlation code (MNZCC) possesses cross-correlation zero to further minimize the multiple access interference, which are found to be more scalable compared to the other existing SAC-OCDMA codes. In this work, the proposed MRDC and MNZCC codes are implemented in an optical system using the optisystem version-12 software for the SAC-OCDMA scheme. Simulation results depict that the OCDMA system based on the proposed novel MNZCC code exhibits better performance compared to the MRDC code and former existing SAC-OCDMA codes. The proposed MNZCC code accommodates maximum number of simultaneous users with higher data rate transmission, lower BER and longer traveling distance without any signal quality degradation as compared to the former existing SAC-OCDMA codes.

Social role-based secure large data objects dissemination in mobile sensing environment

Social role based distributed Large Data Object dissemination framework is proposed.XOR network coding method is introduced in the proposed algorithm.XOR network coding and security framework are seamlessly integrated into PRXeluge.PRXeluge does not bring any additional load to the subscriber nodes. At present, in mobile sensing environment, almost all the existing secure large data objects dissemination algorithms are centralized. The centralized servers publicize the sensing tasks and are also the authorized parties to initiate sensed data dissemination. This paper proposes a novel social role and network coding based security distributed data dissemination algorithm referred as PRXeluge to overcome the shortcomings of existing centralized data dissemination algorithms. Unlike the existing participatory sensing applications, in PRXeluge, service provider just publicizes the sensing tasks and utilizes a conditional proxy re-signature technique to authorize different social roles such as authorized smartphone users to be utilized as a contracted picture reporters, which sense the data and directly disseminate the sensed large data. Furthermore, PRXeluge proposes the XOR (Exclusive-OR) network coding scheme on the basis of Seluge security framework. To maximize the number of successfully decoded packets, PRXeluge introduces a neighbor node table to determine the optimal coding scheme. Experimental results reveal that the proposed PRXeluge shows better performance in terms of lower data packet transmission and dissemination delay compared to that of Seluge. Furthermore, it is observed from the experiment that the proposed algorithm is stronger as compared to that of centralized scheme and performs the fine grain access control without giving any additional load to subscriber nodes.

Comparison of metaheuristic approaches for impairment aware transparent optical networks

In this paper two metaheuristic approaches are compared while solving the dynamic routing and wavelength assignment (DRWA) problem in wavelength division multiplexing (WDM) optical network. In this problem, the effect of Four Wave Mixing (FWM) and amplifier spontaneous emission (ASE) noise are incorporated while solving the problem. The two metaheuristic approaches used in this work are evolutionary programming algorithm (EP) and simulated annealing (SA). These metaheuristic techniques use a common objective function that is designed to reduce the effect of FWM noise and ASE noise on a requested lightpath. The FWM crosstalk products and the static FWM noise power per link are pre computed in order to reduce the set up time of a requested lightpath, and stored in an offline database. These are retrieved during the setting up of a lightpath and evaluated online taking the dynamic parameters like cost of the links into consideration.