Showing papers in "Network Protocols and Algorithms in 2011"

Wireless Sensor Networks for Industrial Process Monitoring and Control: A Survey

Abstract: Normal 0 7.8 磅 0 2 MicrosoftInternetExplorer4 This paper provides a survey on implementing wireless sensor network (WSN) technology on industrial process monitoring and control. First, the existing industrial applications are explored, following with a review of the advantages of adopting WSN technology for industrial control. Then, challenging factors influencing the design and acceptance of wireless sensor networks (WSNs) in the process control world are outlined, and the state-of-the-art research efforts and industrial solutions are provided corresponding to each factor. Further research issues for the realization and improvement of wireless sensor network technology on process industry are also discussed.

Impact of Security Attacks on a New Security Protocol for Mobile Ad Hoc Networks

Abstract: A mobile ad hoc network (MANET) is a self-organized wireless short-lived network consisting of mobile nodes. The mobile nodes communicate with one another by wireless radio links without the use of any pre-established fixed communication network infrastructure. The mobile nodes are vulnerable to different types of security attacks that allow interception, injection, and interference of communication among nodes. Possible damages include leaking secret information, message contamination and node impersonation. MANETs need secure routing protocols to prevent possible security attacks. In this paper, we evaluate the performance of a new security protocol against various known and unknown malicious node attacks. Simulation results have shown that the proposed security protocol resists against malicious nodes with low implementation complexity.

Modified WRR Scheduling Algorithm for WiMAX Networks

Abstract: Worldwide Interoperability for Microwave Access (WiMAX), which is also known as 802.16 standard, supports last-mile broadband access wireless networks. WiMAX has many advantages including wide coverage area and high bandwidth. These advantages enable WiMAX to support long transmission range and high data rate compared to cellular and WiFi network. WiMAX technology uses a number of scheduling techniques in the Medium Access Control (MAC) layer, which is responsible for the utilization of available resources in the networks and distribute them among users in order to ensure the desired quality of service. In this study, we propose a Modified Weighted Round Robin (MWRR) scheduler in order to decrease the average end-to-end delay and improve the average throughput. The proposed scheduling technique has been designed and simulated using the QualNet 5.0.2 network simulator. In order to evaluate the performance of our proposed approach, we compared our results to the results of well-known scheduling techniques (weighted Round Robin (WRR), Strict Priority (SP), and Weighted Fair Queuing (WFQ)). The average percentage of improvement was around 4%.

A Fuzzy Logic Approach for Reducing Handover Latency in Wireless Networks

Abstract: Existing wireless networks aim to provide information communication services between mobile nodes. When a mobile node moves between different radio networks, a handover process is needed to change its point of attachment to the predicted radio network. Since traditional (based on one metric Received Signal Strength Indicator) predictions of handover decisions do not perform well, it is imperative that we develop an intelligent approach to facilitate the handover prediction process, thus yielding seamless handovers. In this article, a Fuzzy logic-based Hand-off Decision (FHD) approach is proposed for wireless networks. The parameters include a Received Signal Strength Indicator and the relative direction of a Mobile Node toward an access point, which are considered as inputs to the fuzzy logic system in order to facilitate the handover decision process and a switch to the best preferable access point. To achieve a fair comparison with a standard handover procedure, we have implemented a fuzzy logic-based hand-off decision approach in Omnet++. Our simulation results show that the proposed approach is able to reduce the handover latency. More precisely, the results show that by using the proposed method, the performance improved significantly the wireless access media delay (link-layer).

Study and Performance of Interior Gateway IP Routing Protocols

Abstract: Large IP networks cannot be possible without routing protocols providing the appropriate paths between end sites. Many interior gateway routing protocols have been developed based on well known algorithms for IP networks in order to prevent routing loops. Some of these interior gateway routing protocols are RIP, OSPF and EIGRP. Each one of them has its benefits and drawbacks, and the best election depends on many parameters such as the network features, network hardware, few bandwidth wastage, scalability, costs, etc. In this paper we present a survey and a test performance of the main interior gateway IP routing protocols (although some of them can work with other non-IP protocols) that are used inside the Autonomous Systems. We will see which one provides the lowest delay path, the lowest number of hops, the lowest convergence time, and how the traffic sent through the network have different behavior depending on the routing protocol running in it, among others. Finally, we will conclude our paper providing some advises to the IP network designers and administrators. This work will help them to take the best election depending on their case.

Protocols and Algorithms for the Next Generation 5G Mobile Systems

Abstract: In this paper we propose new design framework for network architecture of future 5G mobile networks, including protocols and algorithms. The proposed design is based on user-centric mobile environment with many wireless and mobile technologies on the ground. In heterogeneous wireless environment changes in all existing wireless technologies is not possible, so each solution towards the next generation mobile and wireless networks should be implemented in the service stratum, while the radio access technologies belong to the transport stratum regarding the Next Generation Networks approach. In the proposed design the user terminal has possibility to change the Radio Access Technology - RAT based on certain criteria. For the purpose of transparent change of the RATs by the mobile terminal, we introduce so-called Policy-Router as node in the core network, which establishes IP tunnels to the mobile terminal via different available RATs to the terminal. The selection of the RAT is performed by the mobile terminal by using the proposed user agent for multi-criteria decision making based on the experience from the performance measurements performed by the mobile terminal. For the process of performance measurements we introduce the QoSPRO procedure for control information exchange between the mobile terminal and the Policy

A Novel Two-Class Localization Algorithm in Wireless Sensor Networks

Abstract: For most of the applications in wireless sensor networks, localization is fundamental and essential. The localization systems can be categorized into two types: range-based and range-free. In this paper, we propose a new range-free localization algorithm. We define two classes of nodes, according to the number of anchors in the neighborhood. The computation complexity of related algorithms has also been analyzed. The simulation results prove that our proposed two-class algorithm has acceptable complexity, and achieves better precision than the existing ones, such as Centroid, CPE and DV-hop.

Inter-domain Proxy Mobile IPv6 based Vehicular Network

Abstract: Proxy Mobile IPv6 (PMIPv6) was standardized by the Internet Engineering Task Force (IETF) NetLMM WG as a Network-based Mobility management protocol, this protocol allows the Mobile Node (MN) to maintain service connectivity while moving within the PMIPv6 domain. PMIPv6 mobility management is different from the Host-based Mobility management protocols; where the mobility signaling management is controlled by the serving network on behalf of the MN. PMIPv6 introduced new network entities to handle the signaling on behalf of the MN. However, PMIPv6 protocol can only manage the MN’s reachability within a local domain (intra-domain). If the MN moves beyond the perimeter of PMIPv6 domain, the mobility support will be lost. To provide MN continuous support across domains, PMIPv6 needs to be developed to support interconnect neighboring PMIPv6 domains. In this paper we propose an inter-domain handover scheme. The proposed scheme uses the Media Independent Information Service (MIIS) to help the vehicle store information about the network that it is attached with. In addition the Local Mobile Anchor (LMA) will use Fully Qualified Domain Name (FQDN).

MOBILE AGENT BASED ROUTING in MANETS –ATTACKS & DEFENCES

Abstract: A Mobile Adhoc Network (Manet) is a highly challenging environment due to its dynamic topology, limited processing capability, limited storage, band width constraints, high bit error rate and lack of central control. In this dynamic network, each node is considered as a mobile router. A malicious node can easily disrupt the proper functioning of the routing by refusing to forward routing message (misbehavior node), inject the wrong routing packets, modifying routing information, etc. Hence the design of secured routing algorithm is a major issue in Manets. Mobile Agent based algorithms also called Ant Routing algorithms are a class of swarm intelligence and try to map the solution capability of ant colonies for routing in Manets. In this paper we discuss prominent attacks and propose counter-measures in three Ant based routing protocols that are proactive, reactive and hybrid routing.

IMPROVING QoS IN DELAY TOLERANT MOBILE AD HOC NETWORK USING MULTIPLE MESSAGE FERRIES

Abstract: Most ad hoc network routing algorithms are designed primarily for networks that are always connected. While it is certainly desirable to maintain a connected network, various conditions may cause a mobile ad hoc network to become partitioned. If the partitions last for a long duration of time, then it is not possible to deliver a packet from source to destination. To deliver messages in a partitioned network, new routing approaches were proposed for delivering data using message ferries and/or gateways. This paper analyzes various parameters of the routing scheme called Routing with Multiple Message Ferries and Gateways (MMFGW) which eliminates online collaboration between all the communication entities in the network. This paper also investigates the results of simulations, by comparing the performance of our protocols which uses message ferries proposed previously with epidemic routing protocol. The simulation analysis shows that, delivery ratio of MMFGW improves from 35% to 50% with optimal latency and overhead ratio.

Energy-aware Virtual Ring Routing in Wireless Sensor Networks

Abstract: Virtual Ring Routing (VRR) is an ad-hoc routing protocol that avoids flooding the network. It uses location independent identifiers for packet routing. However, VRR does not take into consideration the amount of energy in nodes, leading to the failure of several nodes in the network. To resolve this problem, we have adopted a hierarchical Distributed Hash Table in the VRR architecture. In the resulting architecture, the energy powerful sensors are responsible for most message traffic. Weak sensors are then utilized less frequently than powerful sensors. The experimental results show that Coral-based VRR consumes less energy than VRR and extends the network lifetime.

Anomaly Base Network Intrusion Detection by Using Random Decision Tree and Random Projection: A Fast Network Intrusion Detection Technique

Abstract: Network Intrusion Detection Systems (NIDSs) have become an important component in network security infrastructure. Currently, many NIDSs are rule-based systems whose performances highly depend on their rule sets. Unfortunately, due to the huge volume of network traffic, coding the rules by security experts becomes difficult and time-consuming. Since data mining techniques can build network intrusion detection models adaptively, data mining-based NIDSs have significant advantages over rule-based NIDSs. Network and system security is of paramount importance in the present data communication environment. Hackers and intruders can create many successful attempts to cause the crash of the networks and web services by unauthorized intrusion. New threats and associated solutions to prevent these threats are emerging together with the secured system evolution. Network Intrusion Detection Systems are one of these solutions. The main function of NIDSs is to protect the resources from threats. It analyzes and predicts the behaviors of users, and then these behaviors will be considered an attack or a normal behavior. We use Random projection and Random Tree to detect network intrusions.

Full Geo-localized Mobile Video in Android Mobile Telephones

Abstract: The evolution of mobile telephones have produced smart devices that not only allows the mobile user to talk but also to use a lot of telematic services. High quality photos and videos are produced by smart mobile telephones. The Global Positioning System available in the Mobile telephones allows the user to tag their photos and videos. There are several photo and integral video tagging mobile software but there is not a mobile application that allows the mobile users to tag the full video frames. This full tagging process allows the mobile user to tag independent video frames in order to explode the photo-video properties of the integral video. In this paper we present a mobile application and a Server application that allow the mobile user to full tag the mobile videos and share them with other users (registered in the Server). We present some tradeoffs present in the design of the tagging process.

A Unicast Stable Path Routing Protocol for Mobile Ad hoc Networks based on the Inverse of Link Expiration Time

Abstract: The high-level contribution of this paper is the design and development of a unicast stable path routing protocol (referred to as SILET) that determines long-living routes based on the Inverse of the Link Expiration Times (LET) for Mobile Ad hoc Networks (MANETs). From a graph theoretical perspective, we model SILET as a minimization problem to discover stable routes with the lowest value for the sum of the link weights; the weight of a link defined as 1 plus the inverse of the LETs. The inclusion of ‘1’ in the link weights helps to reduce the number of constituent links of the paths (i.e. the hop count). Performance comparison of SILET with FORP, DSR and ABR routing protocols in ns-2 illustrate that SILET discovers routes whose lifetimes are significantly longer compared to that of DSR and ABR and at most 20-40% lower than that of FORP; the hop counts of SILET routes are at most 4% larger than the minimum hop count; and the end-to-end delay per data packet for SILET routes is the lowest among all the routing protocols simulated – an indication that SILET effectively minimizes the stability-hop count tradeoff observed with the currently available MANET unicast routing protocols.

QoS Traffic Mapping between WiMAX and DiffServ Networks

Abstract: Even when data communications are made inside an all-IP domain, in a hybrid network different mechanisms and policies for the management of Quality of Service (QoS) could coexist in the different access networks and nodes involved. Specifically, in the scenario considered along this work, a WiMAX segment is included inside an IP network using the DiffServ protocol for QoS management. The conflict arises due to the different ways to handle and label traffic flows provided by the DiffServ protocol and the native Medium Access Control (MAC) layer QoS mechanism implemented, and the lack of a one-to-one correspondence between the different classes of traffic defined in both domains. Along this work, a solution to this problem in the form of a traffic mapping system for QoS purposes is presented.

User-Level Quality Assessment of a Delay-Aware Packet Dropping Scheme for VoIP

Abstract: To deal with congestion control in internet protocol (IP) networks, different active queue management schemes have been successfully proposed. However, many of these schemes do not take into consideration the particular Voice over Internet Protocol (VoIP) requirements, thereby potentially penalizing this traffic. In this paper, we propose and evaluate a dropping packet selection algorithm for queue management schemes. This algorithm, called Drop-SwD , protects VoIP traffic without affecting other User Datagram Protocol (UDP) and Transmission Control Protocol (TCP) traffic. Additionally, to preserve the quality of the VoIP service, the proposed algorithm selects the lowest quality packets (with less impact on the subjective quality) to be dropped. The application of the algorithm in different active queue management schemes is evaluated using objective and subjective quality metrics and intelligibility metrics as well. As a result, we show that Drop-SwD improves the final quality of the voice packets’ flow, without degrading the performance of other traffic class, with respect to the packet dropping schemes of reference.

Integration of protocols FHAMIPv6/AODV in Ad hoc networks

Abstract: This paper presents the integration of protocol Fast Hierarchical Ad-Hoc Mobile IPv6 (FHAMIPv6) and the Ad hoc On Demand Distance Vector (AODV). The paper shows the

A Novel Energy Efficient Routing Protocols for Wireless Sensor Networks Using Spatial Correlation Based Collaborative Medium Access Control Combined with Hybrid MAC

Abstract: Wireless Sensor Networks (WSNs) are wireless networks consisting of a group of small, inexpensive nodes, which collect and disseminate significant data. Nodes in a wireless Sensor Networks have various energy and computational constraints due to their inexpensive, random method of deployment. Wireless sensor networks are utilized in a wide range of applications including battlefield surveillance, smart home environments, habitat exploration of animals and vehicle tracking. Energy Efficiency is one critical issue for wireless sensor networks because many sensors are equipped with batteries that have limited life time. This paper introduces the concept of combining two Medium Access Control (MAC) Protocols such as spatial correlation based collaborative medium access control (CCMAC) and Hybrid Medium Access Control (HMAC) which will increase the energy efficiency of the Network. The four various routing protocols explored in this work are AOMDV,AODV, DSR,DSDV. In this paper, comparison of energy efficient routing protocols for Wireless Sensor Networks using spatial correlation based collaborative medium access control (CCMAC) combined with Hybrid Medium Access Control (HMAC) is proposed. Simulation results have been obtained by using Ns2. From the results, the performance of AOMDV is better compared to the other three protocols such as AODV,DSR and DSDV.

Handover latency measurement using variant of capwap protocol

Abstract: The wireless LAN has become increasingly more popular over the past few years. Applications such as audio, video and voice have become important to users in a network environment. As the need for these real-time applications has increased, the handover latency during the movement of the mobile node (MN) has become crucial. A large number of wireless access points require a centralized architecture to manage, control and troubleshoot. The Control and Provision of Wireless Access Points (CAPWAP) Protocol designed by IETF allows Wireless Termination Points (WTP) to be managed centrally by an access controller (AC). This paper briefly describes the CAPWAP architecture and proposes a network setup in which the handover latency is reduced during the movement of mobile node. In particular, it shows if a Generic Routing Encapsulation (GRE) tunnel is produced between the access controllers, the Layer 3 handover latency is reduced. Results are obtained by implementing the Protocol in a test bed for Layer 2 and Layer 3 roaming for data and real-time video streaming.

The Dynamics of Salsa: A Robust Structured P2P System

Abstract: Salsa is a structured peer-to-peer system that is designed to perform robust and reliable lookups. It uses a distributed hash table based on hashes of the nodes’ IP addresses to organize the nodes into groups. With a virtual tree structure, limited knowledge of other nodes is enough to route lookups throughout the system. We use redundancy and bounds checking when performing lookups to prevent malicious nodes from returning false information without detection. We show that our scheme prevents attackers from biasing lookups, while incurring moderate overheads, as long as the fraction of malicious nodes is less than 20%. The number of groups can be used as a tunable parameter to trade-off performance versus security. Salsa is resilient to nodes joining and leaving the system while node lookups are ongoing. The message overhead for system operations in a dynamic network is minimal, with the highest measured message overhead of 0.04 messages per node per minute in simulation time.

Model-based Tracking for Mobile Ad Hoc Networks

Abstract: We consider the problem of tracking of a mobile target node in a mobile ad hoc network (MANET) set-up. We propose a lightweight probabilisticmodel-based tracking protocol (PMBT) that achieves a short catching path with a high success rate. PMBT is a probabilistic online tracking algorithm that computes information utilities at each step, and then chooses the next step toward the target based on the maximum expected utility. Our algorithm avoids the need to maintain a tracking data structure (such as a hierarchical directory look-up structure) and the need to send periodic update messages about the target’s location. Simulation results show, by taking a hybrid approach that integrates a gradient model and a Markov model, our algorithm significantly outperforms both gradient-based and Markov approaches alone.

Controlling P2P File-Sharing Networks' Traffic

Abstract: Since the appearance of Peer-To-Peer file-sharing networks some time ago, many Internet users have chosen this technology to share and search programs, videos, music, documents, etc. The total number of Peer-To-Peer file-sharing users has been increasing and decreasing in the last decade depending on the creation or end of some well known P2P file-sharing systems. P2P file-sharing networks traffic is currently overloading some data networks and it is a major headache for network administrators because it is difficult to control this kind of traffic (mainly because some P2P file-sharing networks encrypt their messages). This article deals with the analysis, taxonomy and characterization of eight Public P2P file-sharing networks: Gnutella, Freeenet, FastTrack, BitTorrent, Opennap, Edonkey, MP2P and Soulseek. These eight most popular networks have been selected due to their different type of working architecture. Then, we will show the amount of users, files and the size of files inside these file-sharing networks. Finally, several network configurations are presented in order to control Peer-to-Peer file-sharing traffic in the network.

A Multifactor Hash Digest Challenge-Response Authentication Scheme for Session Initiation Protocol

Abstract: Authentication is a process by which the sender and the receiver identify the legal communicating partners prior to commencement of message transactions Authentication is a kind of security which is ascertained at the time of initiation of the communication between the two communicating entities like client and server Network communications are found to be vulnerable due to the increase of number of threats from unknown intruders Session Initiation Protocol (SIP) is used for initializing the session between two communicating devices or entities This protocol is widely used in multimedia communications SIP is a powerful signaling protocol which initializes, establishes, maintains, and terminates the session between the communicating devices Many authentication schemes were proposed for SIP from time to time Here we propose a new authentication scheme for SIP based on Multifactor Hash Digest Challenge-Response Sequence Count method This method enhances the SIP authentication and overcomes vulnerability attacks like Password guessing, Server spoofing, Replay, Bucket Brigade and Modification Attacks This method ensures the Confidentiality and Integrity in SIP Authentication process

Quality of Service and security negotiation for autonomous management of Next Generation Networks

Abstract: Based on the IP technology, the next generation networks (NGN) must overcome the main drawbacks of this technology consisting in the lack of quality of service (QoS), security and mobility management. To ensure a service offer in an NGN environment, a protocol for negotiating a service level can be used. However, most of the existing negotiation protocols allow the establishment of a service level which includes only QoS. As for security and mobility, they were often not covered by these negotiations, and therefore managed independently. However, securing a service can cause degradation of the QoS, and the mobility of a user can change the service needs in terms of QoS and security. Thus, we need to simultaneously manage QoS and security while taking into account user’s mobility. In this

Implementation and Evaluation of an M/S Scheme for Inter-Destination Multimedia Synchronization (IDMS)

Abstract: Nowadays, the media consumption model is changing from passive isolated activities towards dynamic group shared experiences. People separated in space can already interact and collaborate within the context of simultaneous media content delivery (e.g. they can launch a real time conversation during a shared video watching). However, to stimulate the acceptance and usability of those socially aware interactive media services, synchronous communications (i.e. consistent playout states) across separated locations must be guaranteed (apart from being integrated with newer social networking technologies). Inter-Destination Multimedia Synchronization (IDMS) has become a key research topic to enable geographically dispersed consumers to experience a satisfying feeling of togetherness. Several (distributed and centralized) approaches to perform IDMS have been adopted by the research community up to date. In this paper, a Master/Slave (M/S) Control Scheme for IDMS is implemented and tested, thus analyzing its strengths and weaknesses for distributed networked environments. Simulation results prove the effectiveness and suitability of the proposed M/S Scheme in those scenarios in which scalability, consistency, interactivity and low control traffic overhead features must be provided.

Distributed Bottleneck Flow Control in Mobile Ad Hoc Networks

Abstract: Flow control in mobile ad hoc networks (MANETs) encounters more challenges than flow control in conventional wired networks, such as channel bandwidth variation, medium contention, and frequent re-routing. Without proper flow control, serious network performance degradation in MANETs has been reported in recent studies. In this paper, we introduce a distributed bottleneck flow control technique in MANETs. The proposed scheme uses a distributed flow control mechanism that has been used in both bottleneck flow control and bandwidth balancing in Distributed-Queue-Dual-Bus (DQDB) in wired networks. It extends bandwidth balancing to operate in a mobile wireless environment. Extensive simulations demonstrate that our flow control scheme is effective and can provide max-min fairness as well as improve Quality of Service (QoS) for flows in MANETs.

Passive Micro-resonator based GMPLS Router for Optical Network-on-Chip

Abstract: Generalized multiprotocol label switching (GMPLS) with wavelength division multiplexing (WDM) technology is a very promising protocol technology for future optical networks. GMPLS technology interconnects new and legacy networks by automating connection provisioning and traffic engineering. The present electrical interconnects for the system on chip (SoC) are unable to satisfy the multiple design requirements of bandwidth, data rate and latency. In this paper, for the first time we have proposed a micro resonator based GMPLS router for optical network on chip (ONoC). The evolution of such a router node on integrated circuit technology will cause the system design to move towards a communication-based architecture. The concept of an integrated GMPLS optical interconnect will be a potential technological solution, alleviating some of the more pressing issues involved in exchanging data between cores in SoC architectures. The investigation for ONoC was carried out at the physical level, where the system performance on the basis of crosstalk, blocking probability, offered traffic load and packet error rate was analyzed.

Wavelength Preference in GMPLS-controlled Wavelength Switched Optical Networks

Abstract: Given the potentialities in terms of high bandwidth, low costs, and low power consumption, Wavelength Switched Optical Networks (WSONs) are the most promising candidate for next generation backbone networks. In WSONs the optical signal is switched at the wavelength granularity, therefore the wavelength assignment process, selecting the carrier of each end-to-end optical connection (i.e., lightpath), plays a crucial role in dynamic network operation. Generalized Multi-Protocol Label Switching (GMPLS) is the standard control plane for WSONs, enabling dynamic lightpath provisioning and maintenance. However, current GMPLS protocol suite does not envision a general mechanism to rank the wavelengths candidate for carrying a lightpath. The lack of wavelength preference in WSONs may cause high blocking probability, wavelength converter waste, and detrimental effects due to physical impairments. This paper reviews several WSON scenarios where the wavelength preference concept is introduced to optimize the wavelength assignment: wavelength continuous, wavelength convertible, and quality of transmission aware WSONs. Automatic ranking of candidate wavelengths is effective to select the most suitable one in each considered scenario. To enforce wavelength preference, an extension to the GMPLS signaling protocol is utilized. Simulation results show that wavelength preference can effectively reduce blocking probability, save wavelength converters, and guarantee lightpath quality of transmission.

Performance Evaluation on Traffic Control in Combined Input and Cross-point Queuing Switches

Abstract: A wide range of emerging networking applications demand computer networks to provide Quality of Service (QoS). Packet switches play a crucial role in computer communications and traffic control in packet switches is a key to QoS provisioning. The Combined Input and Cross-point Queuing (CICQ) switch employs the crossbar-based switching fabric structure with distributed output buffer at switch fabric cross-points. The CICQ switch is being widely deployed in computer networks; therefore control traffic in CICQ switches to provide QoS guarantee becomes an important issue. The research reported in this paper investigates QoS performance of CICQ switches with a variety of traffic control algorithms. Since it is well known that the Output Queuing (OQ) switch is an ideal case that provides the optimal QoS performance, the achievable performance of CICQ and OQ switches with the same traffic control algorithm is compared. The performance analysis in this paper is based on a simulation system developed using OPNET Modeler.

A New Approach For Optimal MIMD Queueless Routing Of Omega and Inverse-Omega Permutations On Hypercubes

Abstract: Omega permutations constitute the subclass of particular permutations which have gained the more attention in the search of optimal routing of permutations in hypercubes. The reason of this attention comes from the fact that they are permutations for general-purpose computing like the simultaneous conflict-free access to the rows or the columns of a matrix. In this paper we address the problem of the optimal routing of omega and inverse-omega permutations on hypercubes under the MIMD queueless communication model. We revisit the problem through a new paradigm: the so-called graphs partitioning in order to take advantage of the recursive structure of the hypercubes topology. We prove that omega and inverse-omega permutations are partitionable. That is any omega (resp. inverse-omega) permutation on n-dimensional hypercube can be decomposed in two independent permutations on two disjoint (n-1)-dimensional hypercubes. We also prove that each one of these permutations is also an omega (resp. inverse-omega) permutation. It follows that any omega (resp. inverse-omega) permutation on n-dimensional hypercube is routable in at most n steps of data exchanges, each step realizing the partition of the hypercube.