Home Node Research Articles

Research on mobility handover for IPv6‐based MANET

ABSTRACTThe paper proposes a mobility handover scheme for IPv6‐based mobile ad hoc network (MANET) Mobility Handover (IMMH). In IMMH, when a node moves out of the communication scope of its upstream node, it is the node that directly establishes the routing path reaching to the upstream node in the Unicast way, which reduces the mobility handover cost and shortens the mobility handover delay. In mobile ad‐hoc networks without any infrastructures, a user always uses a node's home address to communicate with the node, and both the node's mobility handover process and its care‐of address update process are transparent to the user. Therefore, the communication continuity is ensured. From both the theoretical perspective and the simulative perspective, the paper analyzes the performance parameters of IMMH, including the mobility handover cost and the mobility handover delay. The data results show that the mobility handover cost of IMMH is lower and the delay is shorter.Copyright © 2012 John Wiley & Sons, Ltd.

IP Multimedia subsystem authentication protocol in LTE-heterogeneous networks

AbstractIP Multimedia Subsystem (IMS) introduces important advantages for users of LTE-femtocell heterogeneous access networks. In order to access services hosted in the IMS layer, the user has to undergo authentication procedure with the access network, followed by an authentication procedure with the IMS layer. This multi-pass authentication procedure is essential for securing IMS from malicious users, resulting in added overhead and possible quality of service degradations. The problem is further compounded when the user moves from one femtocell domain into another, which requires the authentication procedure to be repeated. To mitigate this problem, we present a lightweight, robust, and architecture-compatible IMS authentication protocol that implements a one-pass IMS procedure by promoting efficient key re-use for a mobile user. We make use of Home Node B femtocells to perform the role of IMS proxy. To verify the feasibility of using our protocol in mobile networks, an abstract model of our protocol is derived. The abstract model is emulated using Asterisk server and virtualization techniques. We also analyze the authentication delay of our proposed scheme. Numerical results reveal a reduction in user authentication delay of more than 50 percent compared to the existing authentication procedure.

Homing‐pigeon‐based messaging: multiple pigeon‐assisted delivery in delay‐tolerant networks

ABSTRACTIn this paper, we consider the applications of delay‐tolerant networks (DTNs), where the nodes in a network are located in separated areas, and in each separated area, there exists (at least) an anchor node that provides regional network coverage for the nearby nodes. The anchor nodes are responsible for collecting and distributing messages for the nodes in the vicinity. This work proposes to use a set of messengers (named pigeons) that move around the network to deliver messages among multiple anchor nodes. Each source node (anchor node or Internet access point) owns multiple dedicated pigeons, and each pigeon takes a round trip starting from its home (i.e., the source) through the destination anchor nodes and then returns home, disseminating the messages on its way. We named this as a homing‐pigeon‐based messaging (HoPM) scheme. The HoPM scheme is different from the prior schemes in that each messenger is completely dedicated to its home node for providing messaging service. We obtained the average message delay of HoPM scheme in DTN through theoretical analysis with three different pigeon scheduling schemes. The analytical model was validated by simulations. We also studied the effects of several key parameters on the system performance and compared the results with previous solutions. The results allowed us to better understand the impacts of different scheduling schemes on the system performance of HoPM and demonstrated that our proposed scheme outperforms the previous ones. Copyright © 2011 John Wiley & Sons, Ltd.

Mobility Management in Identifier/Locator Split Networks

In the traditional Transmission Control Protocol/Internet Protocol (TCP/IP) stack, IP address represents not only the identifier but also the location of a node so that it can not provide global roaming seamless. To address this problem, MIP (Mobile IP) uses dynamical care-of-address to indicate the location of a mobile node (MN) and stable home address to indicate its identifier. However, such a separation of MIP can not support routing scalability, location privacy, and manageability. In this paper, we propose an identifier/locator split architecture which contains an overlay mapping system to store identifier-to-locator mappings and manage mobile nodes' behavior. In addition, we design a novel mobility management scheme based on the identifier/locator split architecture (MMILS) which can address the above issues of MIP. To reduce the amount of signaling and enhance the performance, we distinguish micro-mobility and macro-mobility by introducing an Agent Tunnel Router (ATR). For micro-mobility, the ATR keeps the MN's identifier-to-locator mapping invariable, so it avoids the mapping update in the mapping system and the Tunnel Route (TR) of each correspondent node. For macro-mobility, to support fast update and handover, we design a united mapping table in the ATR. And then, we estimate the number of entries and the required storage space to validate it feasible. To evaluate the efficiency of MMILS, we analyze the signaling cost by establishing an analytical model and implement it in our test-bed. The results demonstrate that the proposed scheme can effectively reduce signaling traffic and has a low handover delay compared to MIP and HMIP (Hierarchical Mobile IP).

On the Use of Home Node Bs for Emergency Telemedicine Applications in Various Indoor Environments

The use of emergency telemedicine applications at the site of a medical emergency event provides a multitude of benefits, both from the perspective of the patient and the emergency care providers. Innovations in rich multimedia telemedicine solutions further enhances the aforementioned benefits, but places more stringent quality-of-service demands on the underlying mobile networks. In this paper, the authors present a proposal for a complementary solution for rapid provisioning of mobile broadband data connectivity for emergency telemedicine applications in indoor environments. The proposed solution relies on the exploitation of existing femtocellular network resources available at emergency sites in various residential building types. Simulations carried out for a UMTS network environment demonstrate significant improvements in terms of achievable throughput for the emergency mobile terminal device when access to UMTS Home Node Bs available in the building is allowed for emergencies compared to macro Node B access only.

A Home Automation system based on Smart phone

Smart Home or Home Network technology is one that continuously creates added value, making a better life. This paper designed and developed a smart home control system using smart phone. This proposed smart home system consists of home server control system, remote smart application system and home node structure. Home node structure, in detail, is composed of intrusion detection, gas leakage or gas valve control, door lock, automatic curtain, ventilation control and On/Off control modules and these modules are controlled at home server. Home server makes it easy to control home automatic control system anytime, anywhere as it provides remote interface that enables control via smartphone and user interface in itself.

HoP-DTN: Modeling and Evaluation of Homing-Pigeon-Based Delay-Tolerant Networks

The development of delay-tolerant networks (DTNs) has attracted significant attention in the network research community. In this paper, we propose a new type of DTN - a homing-pigeon-based DTN (HoP-DTN). In the HoP-DTN, each node owns a dedicated messenger (called a pigeon). The only form of internode communication is for a pigeon to periodically carry a batch of messages originated at the home node, deliver them to the corresponding destination nodes, and return home. Clearly, given message-expiration times, some messages may not reach their destinations by the deadline. Through analysis and simulations, we study the relationship between key parameters of the system, including average message delay, expiration time, delivery ratio, arrival rate, and batch size of messages. Various simulations have been conducted to demonstrate the accuracy of our analysis. Our theoretical study and simulations present a deep insight into the characteristics of the proposed system. Some interesting observations from simulations are discussed in detail in this paper, and the results demonstrate that our proposed scheme performs better in terms of average message delay, message-delivery ratio, and cost-effectiveness.

Performance evaluation of directory protocols on an optical broadcast-based distributed shared memory multiprocessor

Recent advances in the development of optical technologies suggest the possible emergence of broadcast-based optical interconnects within cache–coherent distributed shared memory (DSM) multiprocessor architectures. It is well known that the cache–coherence protocol is a critical issue in designing such architectures because it directly affects memory latencies. In this paper, we evaluate via simulation the performance of three directory-based cache–coherence protocols; strict request–response, intervention forwarding and reply forwarding on the Simultaneous Optical Multiprocessor Exchange Bus (SOME-Bus), which is a low-latency and high-bandwidth broadcast-based fiber-optic interconnection network supporting DSM. The simulated system contains 64 nodes, each of which has a processor, a cache controller, a directory controller and an output channel. Simulations have been conducted for each protocol to measure average processor utilization, average network latency and average number of packets transferred over the network for varying values of the important DSM parameters such as the ratio of the mean channel service time to mean thread run time ( T/R), probability of a cache block being in modified state { P( M)}, the fraction of write misses { P( W)} and home node contention rate. The results reveal that for all cases, except for low values of P( M), intervention forwarding gives the worst performance (lowest processor utilization and highest latency). The performance of strict request–response and reply forwarding is comparable for several values of the DSM parameters and contention rate. For a contention rate of 0%, the increase of P( M) makes reply forwarding perform better than strict request–response. The performance of all protocols decreases with the increase of P( W) and contention rate. However, the performance of strict request–response is the least affected among other protocols due to the negative impact of the increase of P( W) and contention rate. Therefore, for the full contention case (i.e. contention rate of 100%); for low values of P( M), or for mid values of P( M) and high values of P( W), strict request–response performs better than reply forwarding. These results are significant in the sense that they provide an insight to multiprocessor architecture designers for comparing the performance of different directory-based cache–coherence protocols on a broadcast-based interconnection network for different values of the DSM parameters and varying rates of contention.

On the Hamiltonicity Gap and doubly stochastic matrices

AbstractWe consider the Hamiltonian cycle problem embedded in singularly perturbed (controlled) Markov chains. We also consider a functional on the space of stationary policies of the process that consists of the (1,1)‐entry of the fundamental matrices of the Markov chains induced by these policies. We focus on the subset of these policies that induce doubly stochastic probability transition matrices which we refer to as the “doubly stochastic policies.” We show that when the perturbation parameter, ε, is sufficiently small, the minimum of this functional over the space of the doubly stochastic policies is attained at a Hamiltonian cycle, provided that the graph is Hamiltonian. We also show that when the graph is non‐Hamiltonian, the above minimum is strictly greater than that in a Hamiltonian case. We call the size of this difference the “Hamiltonicity Gap” and derive a conservative lower bound for this gap. Our results imply that the Hamiltonian cycle problem is equivalent to the problem of minimizing the variance of the first hitting time of the home node, over doubly stochastic policies. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2009

Two proposals for the inclusion of directory information in the last-level private caches of glueless shared-memory multiprocessors

In glueless shared-memory multiprocessors where cache coherence is usually maintained using a directory-based protocol, the fast access to the on-chip components (caches and network router, among others) contrasts with the much slower main memory. Unfortunately, directory-based protocols need to obtain the sharing status of every memory block before coherence actions can be performed. This information has traditionally been stored in main memory, and therefore these cache coherence protocols are far from being optimal. In this work, we propose two alternative designs for the last-level private cache of glueless shared-memory multiprocessors: the lightweight directory and the SGluM cache. Our proposals completely remove directory information from main memory and store it in the home node’s L2 cache, thus reducing both the number of accesses to main memory and the directory memory overhead. The main characteristics of the lightweight directory are its simplicity and the significant improvement in the execution time for most applications. Its drawback, however, is that the performance of some particular applications could be degraded. On the other hand, the SGluM cache offers more modest improvements in execution time for all the applications by adding some extra structures that cope with the cases in which the lightweight directory fails.

Towards implementation of a novel scheme for data prefetching on distributed shared memory systems

High speed networks and rapidly improving microprocessor performance make the network of workstations an extremely important tool for parallel computing in order to speedup the execution of scientific applications. Shared memory is an attractive programming model for designing parallel and distributed applications, where the programmer can focus on algorithmic development rather than data partition and communication. Based on this important characteristic, the design of systems to provide the shared memory abstraction on physically distributed memory machines has been developed, known as Distributed Shared Memory (DSM). DSM is built using specific software to combine a number of computer hardware resources into one computing environment. Such an environment not only provides an easy way to execute parallel applications, but also combines available computational resources with the purpose of speeding up execution of these applications. DSM systems need to maintain data consistency in memory, which usually leads to communication overhead. Therefore, there exists a number of strategies that can be used to overcome this overhead issue and improve overall performance. Strategies as prefetching have been proven to show great performance in DSM systems, since they can reduce data access communication latencies from remote nodes. On the other hand, these strategies also transfer unnecessary prefetching pages to remote nodes. In this research paper, we focus on the access pattern during execution of a parallel application, and then analyze the data type and behavior of parallel applications. We propose an adaptive data classification scheme to improve prefetching strategy with the goal to improve overall performance. Adaptive data classification scheme classifies data according to the accessing sequence of pages, so that the home node uses past history access patterns of remote nodes to decide whether it needs to transfer related pages to remote nodes. From experimental results, we can observe that our proposed method can increase the accuracy of data access in effective prefetch strategy by reducing the number of page faults and misprefetching. Experimental results using our proposed classification scheme show a performance improvement of about 9---25% over the same benchmark applications running on top of an original JIAJIA DSM system.

Design and Implementation of an Agent Home Scheme Strategy for Prefetch-Based DSM Systems

In recent years, cluster computing has been widely investigated and there is no doubt that it can provide a cost-effective computing infrastructure by aggregating computational power, communication, and storage resources. Moreover, it is also considered to be a very attractive platform for low-cost supercomputing. Distributed shared memory (DSM) systems utilize the physical memory of each computing node interconnected in a private network to form a global virtual shared memory. Since this global shared memory is distributed among the computing nodes, accessing the data located in remote computing nodes is an absolute necessity. However, this action will result in significant remote memory access latencies which are major sources of overhead in DSM systems. For these reasons, in order to increase overall system performance and decrease this overhead, a number of strategies have been devised. Prefetching is one such approach which can reduce latencies, although it always increases the workload in the home nodes. In this paper, we propose a scheme named Agent Home Scheme. Its most noticeable feature, when compared to other schemes, is that the agent home distributes the workloads of each computing nodes when sending data. By doing this, we can reduce not only the workload of the home nodes by balancing the workload for each node, but also the waiting time. Experimental results show that the proposed method can obtain about 20% higher performance than the original JIAJIA, about 18% more than History Prefetching Strategy (HPS), and about 10% higher than Effective Prefetch Strategy (EPS).

Lazy home-based protocol for a software distributed shared memory system

This paper presents the design and implementation of our novel home-based software Distributed Shared Memory (DSM) system. We call our system Lazy Home-based Scope Consistency (LHScC) since the system implements scope consistency lazily based on the home-based protocol. Our technique is different from others in that an optimum home node is decided before updating a home node. The performance evaluation shows that LHScC is more scalable than other DSM systems and removes the home assignment problem in the usual home-based protocol.

Zone Repartitioning: A Load‐Balancing Mechanism for Data‐Centric Storage Systems

Data‐centric storage is an efficient scheme to store and retrieve event data in sensor networks, but with the multi‐hop routing nature of sensor networks, the communication cost of the home nodes and their neighboring nodes tends to be much higher than the other nodes. These hot‐spots can adversely impact system lifetime by draining off their limited energy rapidly. In this paper, we present Zone‐Repartitioning, a load‐balancing mechanism that reduces the energy consumption of the hot‐spots by distributing their communication load while event frequency is high. The trade‐off between event storage cost and query cost makes Zone Repartitioning a competitive approach in different kinds of applications. We compare the performance of Zone Repartitioning against GHT and show that Zone Repartitioning provides better adaptability in various sensor network scenarios.

A Load Balance Data Storage Method Based on Ring for Sensor Networks

The traditional data centric storage method has a serious problem named hotspot problem, which appears near the sink and home node. Hotspot problem causes the nodes near the hotspot consume much more energy than other nodes, which seriously shortens the lifetime of the sensor networks. In this paper, a method distributing multiple sink nodes around the sensor networks is proposed to solve the hotspot problem around the sink. A load balance data storage method based on ring and a query processing algorithm for such a kind of data storage method are proposed to solve the hotspot problem around the home node. First, the ring based load balance data storage method divides the sensor networks into a lot of rings and stores data among all nodes within a ring. Second, different rings alternatively work during the working time of the network, which avoids the hotspot problem further. Finally, the query processing algorithm based on the load balance data storage method makes all nodes within a ring cooperatively answer the user’s query. Although the ring based load balance data storage method and the query processing algorithm consume more energy than the traditional method when answering a user’s query, the method makes all nodes within the network consume energy evenly, which avoids the hotspot problem of the traditional method, so the lifetime of sensor networks can be extended. Experimental results also show that the ring based load balance data storage method and the query processing algorithm can solve the hotspot problem and prolong the lifetime of the sensor networks.

대규모 이동 에이전트 시스템을 위한 적응적 에이전트간 통신 프로토콜

This paper proposes an adaptive inter-agent communication protocol to considerably reduce the amount of agent location information maintained by each service node and the message delivery time while avoiding the dependency of the home node of a mobile agent. To satisfy this goal, the protocol enables each mobile agent to autonomously leave its location information only on some few of its visiting nodes. Also, it may significantly reduce the agent cache updating frequency of each service node by keeping the identifier of the location manager of each agent in the smart agent location cache of the node. Simulation results show that the proposed protocol reduces about of message delivery overhead and about of the amount of agent location information each service node should maintain compared with the traditional one.

Two energy efficient algorithms for tracking objects in a sensor network

AbstractWe propose two energy efficient algorithms for locating a target object moving in an area covered by a wireless ad hoc network. The first algorithm developed conserve energy by efficiently identifying sensor nodes, as Home Nodes, and use only local messages between neighboring nodes to follow the trail of the object. Since we avoid the long‐range transmission and maximize the localization, the algorithms reduce the communication cost. The dynamic nature of the second algorithm exploits the predefined parameters such as the object velocity. Our algorithm represents query shipping against the conventional data shipping as a means to reduce the amount of data being shipped across the network. Hence, it locates the objects over the network with minimal energy conservation using short‐range message transmissions. The performance analysis (both experimental and theoretical) shows the effectiveness of the two algorithms in comparison to another tracking algorithm. Copyright © 2006 John Wiley & Sons, Ltd.

Home-based Cooperative Cache for parallel I/O applications

Recently, there has been much research about cluster computing to get high performance using low-cost nodes connected with high-speed networks. In many research fields, many I/O subsystems which access disks slower than any other component in cluster computing have been proposed such as parallel distributed file systems and Cooperative Cache. In many I/O subsystems, Cooperative Cache was proposed to reduce servers’ load and to achieve high performance by sharing nodes’ caches. Previous researches about Cooperative Cache focus on how to efficiently manage read caches and do not care about the write policy. In parallel I/O applications, which use cluster computing, there are many write accesses as well as read accesses. To improve the overall I/O performance, it is necessary to improve write performance as well as read performance. In this paper, we propose the home-based Cooperative Cache. In the home-based Cooperative Cache, every block has its static home. The home node of a block does the read caching and the write buffering of the block. We apply the home-based Cooperative Cache to Parallel Virtual File System (PVFS) and Cooperative Cluster File System (CCFS). Also, we evaluate and analyze the performance of the home-based Cooperative Cache in PVFS and in CCFS.

Optimización en la asignación de tareas en un sistema de guardería forestal

SUMMARY We solved the forest ranger assignment problem (FRAP) by using the algorithm of the nearest location in the salesman traveling problem (STP). The FRAP consists of assigning tasks to a system of surveillance and forest administration. The solution proposal is to apply a solution to the problem that optimizes the tasks of forest rangers supervising 27.000 ha of forest with 102 sectors, and 402 nodes. The algorithm is evaluated twice a year, winter and summer. There are two initial solution forms (1) To roam forest rangers that leave the home node randomly or (2) to go to the nearest location. Neither solution differs significantly, either in cost or total distance traveled. The forest rangers can be scheduling with 99% accuracy, thus creating a considerable improvement over the already existing one.

The impact of negative acknowledgments in shared memory scientific applications

Negative acknowledgments (NACKs) and subsequent retries, used to resolve races and to enforce a total order among shared memory accesses in distributed shared memory (DSM) multiprocessors, not only introduce extra network traffic and contention, but also increase node controller occupancy, especially at the home. We present possible protocol optimizations to minimize these retries and offer a thorough study of the performance effects of these messages on six scalable scientific applications running on 64-node systems and larger. To eliminate NACKs, we present a mechanism to queue pending requests at the main memory of the home node and augment it with a novel technique of combining pending read requests, thereby accelerating the parallel execution for 64 nodes by as much as 41 percent (a speedup of 1.41) compared to a modified version of the SGI Origin 2000 protocol. We further design and evaluate a protocol by combining this mechanism with a technique that we call write string forwarding, used in the AlphaServer GS320 and Piranha systems. We find that without careful design considerations, especially regarding atomic read-modify-write operations, this aggressive write forwarding can hurt performance. We identify and evaluate the necessary micro-architectural support to solve this problem. We compare the performance of these novel NACK-free protocols with a base bitvector protocol, a modified version of the SGI Origin 2000 protocol, and a NACK-free protocol that uses dirty sharing and write string forwarding as in the Piranha system. To understand the effects of network speed and topology the evaluation is carried out on three network configurations.