Pointer Forwarding Research Articles

An optimized protocol for cost effective communication in a multi-agent environment

Mobile agents can migrate and communicate through interaction messages in a multi-agent environment. A multi-agent environment should provide a mechanism where mobile agents can be tracked easily and communication among them can take place while consuming the least amount of resources. Among all the proposed schemes the home based and forward pointing based scheme seems to be the best in achieving the desired objectives. The analysis shows that besides offering some advantages the aforementioned approach suffers from using high amounts of memory, high transmission cost, and the single point of failure problems. In this research we propose managing forwarding pointers intelligently by removing them from hosts when they are not required, preventing unnecessary update messages when the agent's mobility goes high, calculating the shortest path instantly after the agent's migration, and acknowledging only high priority interaction messages. We have validated our proposed approach with the help of experiments on a simulation tool OCEMAgents. The results show that the proposed approach has achieved all the objectives that are claimed and it has reduced memory and network overhead by minimizing the usage of forwarding pointers and by reducing the transmission cost. Besides that the proposed approach can effectively handle the single point of failure problem. Based on the results, we can safely declare that the proposed approach can be cost-effective if it is implemented in a real multi-agent system.

멀티캐스트 서비스를 지원하는 포인터 포워딩 방식의 분산 이동성 관리 시스템

In order to cope with rapidly increasing mobile traffic, a system that distributes mobility management functions to access routers is being studied. Because the distributed mobility management system eliminates the need for centralized devices, it allows each access router to enable more efficient packet delivery and is not limited to the performance of specific network devices. In addition, as video services proliferate, a method for effectively providing a multicast service is becoming more important. In this paper, we propose a novel method for a distributed mobility management system supporting a multicast service. As the multicast service provides the same content for many users, we propose a pointer forwarding technique to take advantage of the multicast service state already used by other users and mathematically analyze the performance.

Relationship between the iris connective tissue integrity in patients with chronic fatigue diagnosed with Qi deficiency syndrome

Mobile agents can migrate and communicate through interaction messages in a multi-agent environment. A multi-agent environment should provide a mechanism where mobile agents can be tracked easily and communication among them can take place while consuming the least amount of resources. Among all the proposed schemes the home based and forward pointing based scheme seems to be the best in achieving the desired objectives. The analysis shows that besides offering some advantages the aforementioned approach suffers from using high amounts of memory, high transmission cost, and the single point of failure problems. In this research we propose managing forwarding pointers intelligently by removing them from hosts when they are not required, preventing unnecessary update messages when the agent's mobility goes high, calculating the shortest path instantly after the agent's migration, and acknowledging only high priority interaction messages. We have validated our proposed approach with the help of experiments on a simulation tool OCEMAgents. The results show that the proposed approach has achieved all the objectives that are claimed and it has reduced memory and network overhead by minimizing the usage of forwarding pointers and by reducing the transmission cost. Besides that the proposed approach can effectively handle the single point of failure problem. Based on the results, we can safely declare that the proposed approach can be cost-effective if it is implemented in a real multi-agent system.

A multi-hop pointer forwarding scheme for efficient location update in low-rate wireless mesh networks

Recently, a pointer forwarding scheme (PFS) was proposed to reduce location update overhead in wireless mesh networks. Using PFS, a location update is replaced with a simple forwarding pointer setup between two neighboring mesh routers (MRs). However, in PFS, if the two MRs are not one hop neighbors, PFS fails to set up a forwarding pointer, thus increasing location update overhead. To improve PFS, we present a multi-hop pointer forwarding scheme (MPFS). MPFS allows forwarding pointers to be constructed over multi-hop at once even if MRs are not one hop neighbor by using logical tree distance constructed during network formation. The tree distance is used to relay forwarding pointer packets over multi-hop links without additional control overhead during forwarding pointer setup and to estimate hop distance between two MRs. By doing so, MPFS improves the probability of success in forwarding pointer setup while ensuring k≤km, resulting in lowering the location update overhead. Also, we analyze pointer forwarding success probability and average chain length and discuss why MPFS is suitable for resource-constrained LRWMNs. Using ns-2, we show that MPFS significantly reduces the number of location update events, location update delay and signaling overhead, and packet losses during location updates. With real-world implementation, we also confirm feasibility of MPFS.

Dynamic mobility management scheme for inter handoff in hybrid wireless mesh networks

Our work focuses to determine the more reliable routing path to increase the quality of service with fast route recovery process and also to find the most effective path for transmitting the same data towards multiple destination nodes. Thus in this paper we have proposed to design a dynamic mobility management scheme for inter handoff in WMN. For mobility, the inter-domain mobility management scheme is applied. To reduce the overall network traffic incurred by this mobility management, the dynamic pointer forwarding scheme for internet traffic is used. Simulation results show that the proposed mobility management scheme provides reduced packet drop and delay when compared with the existing scheme.

Intra-MARIO: A Fast Mobility Management Protocol for 6LoWPAN

One of the major challenges in 6LoWPAN is to provide continuous services while mobile nodes’ movements with minimizing network inaccessible time caused due to handoffs. Even though MIPv6, HMIPv6, and PMIPv6 are commonly accepted standards to address this in IP networks, they cannot inherently avoid the degradation in communication quality during handoff, since they are not designed with consideration of constrained node networks like 6LoWPAN. In this paper, we propose a new fast mobility management protocol for 6LoWPAN, named intra-MARIO. To minimize handoff delay and enhance service availability, intra-MARIO introduces three important components, which are a fast rejoin scheme for handoff management with an adaptive polling based movement detection and multi-hop pointer forwarding schemes for location management. To justify the effectiveness, we have conducted extensive simulations by comparing intra-MARIO with prior schemes like a basic mobility management scheme and a PMIPv6-based protocol. We then implement intra-MARIO on top of our 6LoWPAN platform (SNAIL) and evaluate the performance of intra-MARIO. The results highlight that intra-MARIO reduces overall handoff delay with low power consumption and minimizes packet losses during handoffs, compared to prior mobility protocols.

Dynamic mobility management scheme for inter handoff in hybrid wireless mesh networks

Our work focuses to determine the more reliable routing path to increase the quality of service with fast route recovery process and also to find the most effective path for transmitting the same data towards multiple destination nodes. Thus in this paper we have proposed to design a dynamic mobility management scheme for inter handoff in WMN. For mobility, the inter-domain mobility management scheme is applied. To reduce the overall network traffic incurred by this mobility management, the dynamic pointer forwarding scheme for internet traffic is used. Simulation results show that the proposed mobility management scheme provides reduced packet drop and delay when compared with the existing scheme.

Dealing With Mobility-Caused Outdated Mappings in Networks With Identifier/Locator Separation

In networks with identifier/locator separation, packets from a source to a destination are generally tunneled from the source’s ingress tunnel router (ITR) to the destination’s egress tunnel router (ETR). In addition, the source’s ITR often caches the destination’s identifier-to-locator mapping for a certain duration, called cache timeout, in order to avoid frequently querying mapping servers. When the destination moves from an old ETR to a new one, its identifier-to-locator mapping changes accordingly, which makes the destination’s identifier-to-locator mapping cached at some ITRs outdated. While several approaches have been proposed to address this issue, they either cannot deal with all types of outdated mappings cached at the ITRs or face the triangular routing problem. Accordingly, in this paper, we propose a timer-based pointer forwarding (TBPF) approach that can deal with all types of outdated mappings and avoid the triangular routing problem. We present numerical results to compare TBPF with existing approaches and show that TBPF is a very promising solution for dealing with outdated mappings.

Distributed Mobility Management Strategy with Pointer Forwarding Technique

With the dramatic increase in mobile traffic in recent years, some of the limitations of mobility management frameworks have magnified. The current centralized mobility management (CMM) strategy has various problems, such as a suboptimal routing path, low scalability, signaling overhead, and a single point of failure. To overcome these weaknesses in the CMM strategy, the Internet Engineering Task Force has been discussing distributed mobility management (DMM) strategies. The fundamental concept of a DMM strategy is to distribute the mobility anchors closer to the users. While the distribution of mobility anchors results in low-cost traffic delivery, it increases the signaling cost. To reduce this higher signaling cost, we propose a new DMM strategy applying the pointer forwarding technique. The proposed strategy keeps the existing tunnels and extends the traffic path as much as possible. In this paper, we analyze the performance of the pointer forwarding-DMM strategy and discuss its pros and cons.

Cost-effective handoff scheme based on mobility-aware dual pointer forwarding in proxy mobile IPv6 networks

In this paper, a mobility-aware Dual Pointer Forwarding scheme (mDPF) is applied in Proxy Mobile IPv6 (PMIPv6) networks. The movement of a Mobile Node (MN) is classified as intra-domain and inter-domain handoff. When the MN moves, this scheme can reduce the high signaling overhead for intra-handoff/inter-handoff, because the Local Mobility Anchor (LMA) and Mobile Access Gateway (MAG) are connected by pointer chains. In other words, a handoff is aware of low mobility between the previously attached MAG (pMAG) and newly attached MAG (nMAG), and another handoff between the previously attached LMA (pLMA) and newly attached LMA (nLMA) is aware of high mobility. Based on these mobility-aware binding updates, the overhead of the packet delivery can be reduced. Also, we analyse the binding update cost and packet delivery cost for route optimization, based on the mathematical analytic model. Analytical results show that our mDPF outperforms the PMIPv6 and the other pointer forwarding schemes, in terms of reducing the total cost of signaling.

State-Aware Pointer Forwarding Scheme With Fast Handover Support in a PMIPv6 Domain

Proxy mobile IPv6 (PMIPv6) has been developed as a network-based mobility management protocol by the Internet Engineering Task Force. Mobility for individual mobile nodes (MNs) is supported by network entities. PMIPv6 thus eliminates mobility signaling from the MNs as it does not require a mobility stack at the MNs. However, during handovers of MNs, PMIPv6 induces unnecessary location update traffic and suffers the packet loss, which downgrades the quality of mobility support. In this paper, we introduce a state-aware pointer forwarding scheme with fast handover support, called FC-PMIPv6, to further enhance the performance of mobility support in a PMIPv6 domain. In FC-PMIPv6, a pointer forwarding chain between mobility access gateways (MAGs) is established to reduce location update traffic to a local mobility anchor during handovers of an MN. The current mobility state of the MN is also considered in deciding whether the forwarding chain should be prolonged or refreshed by an MAG serving the MN. This mobility state consideration in pointer forwarding reduces unnecessary traffic for the location update and guarantees the efficiency of packet transmission. In addition, a fast handover process is adopted to reduce the handover latency and avoid the packet loss during handovers. We develop analytical models to study the performance of FC-PMIPv6, which consider both the signaling cost and the packet transmission cost. Numerical results not only demonstrate that FC-PMIPv6 outperforms the basic PMIPv6 protocol, but also present a relationship between an optimized length of a forwarding chain and a mobility state of an MN. From the conducted numerical results, for example, it is shown that the signaling cost of FC-PMIPv6 is enhanced up to 23% over the basic PMIPv6 protocol. In addition, simulation results on the weighted signaling cost are provided to demonstrate the performance improvement of our FC-PMIPv6 compared with the basic PMIPv6 protocol.

Hybrid Scheme with Adaptive Replication and Mobility Anchoring Point (MAP) in Wireless Networks

Replication strategy is mostly useful for replicating the mobile user's profile at selected locations from which some callers have higher calling rate. Location management scheme also include replication strategy to reduce the location lookup cost of called mobile user. It plays important role in personal communication services in order to reduce call setup cost, call setup time, and increases the QoS (quality of service). In prior replication schemes, called user's location profile is placed at some fixed and limited number of visitor location registers (VLRs) based on call history of the caller. In prior hybrid schemes location update and replication strategies are combined together. These prior hybrid schemes apply pointer forwarding strategy and replication. But these schemes have limitations like holding "loose" form of location profile and higher location update cost. We have proposed a new hybrid scheme which includes adaptive replication of updated user's location profile and mobility anchoring point (MAP) for location update. The main objective of the proposed scheme is to reduce call setup cost and call setup time. In order to achieve the objective, adaptive replication is applied at certain visitor location registers (VLRs) according to movement of caller. The replica is kept updated at MAP and replicated to neighbor VLRs as per movement of the caller. We have presented fluid-flow based analytical modeling which shows that proposed scheme outperforms the prior hybrid scheme.

Location management with the self-similar stream

The mobile communication location management with a self-similar stream is studied. In this paper, we propose a model of a pointer forwarding strategy with the self-similar stream and propose the model a pointer forwarding strategy with threshold for mobility management. This paper investigates these models and obtains probability formulas of the count of the location areas for a mobile crossing by overcoming analytic difficulty. These results provide a theoretical basis for quantitative evaluation of mobility management.

Mobility Management in Wireless Mesh Networks Utilizing Location Routing and Pointer Forwarding

We propose and analyze LMMesh: a routing-based location management scheme with pointer forwarding for wireless mesh networks. LMMesh integrates routing-based location update and pointer forwarding by exploiting the advantages of both methods, while avoiding their drawbacks. It considers the effect of the integration on the overall network cost incurred by location management and packet delivery. By exploring the tradeoff between the service cost for packet delivery and the signaling cost for location management, LMMesh identifies the optimal protocol setting that minimizes the overall network cost on a per-user basis for each individual mesh client, when given a set of parameter values characterizing the specific mobility and service characteristics of the mesh client. We develop an analytical model based on stochastic Petri net techniques for analyzing the performance of LMMesh and a computational procedure for calculating the overall network cost. Through a comparative performance study, we show that LMMesh outperforms both pure routing-based location management schemes and pure pointer forwarding schemes, as well as traditional tunnel-based location management schemes.

프록시 모바일 IPv6 네트워크에서 포인터 포워딩에 기반한 비용효과적인 이동성관리 기법

We propose efficient mobility management schemes based on pointer forwarding for Proxy Mobile IPv6 Networks(PMIPv6) with the objective to reduce the overall network traffic incurred by mobility management and packet delivery. The proposed schemes are per-user-based, i.e., the optimal threshold of the forwarding chain length that minimizes the overall network traffic is dynamically determined for each individual mobile user, based on the user`s specific mobility and service patterns. We demonstrate that there exists an optimal threshold of the forwarding chain length, given a set of parameters characterizing the specific mobility and service patterns of a mobile user. We also demonstrate that our schemes yield significantly better performance than schemes that apply a static threshold to all mobile users. A comparative analysis shows that our pointer forwarding schemes outperform routing-based mobility management protocols for PMIPv6.

Eliminating read barriers through procrastination and cleanliness

Managed languages typically use read barriers to interpret forwarding pointers introduced to keep track of copied objects. For example, in a multicore environment with thread-local heaps and a global, shared heap, an object initially allocated on a local heap may be copied to a shared heap if it becomes the source of a store operation whose target location resides on the shared heap. As part of the copy operation, a forwarding pointer may be established in the original object to point to the copied object. This level of indirection avoids the need to update all of the references to the object that has been copied. In this paper, we consider the design of a managed runtime that eliminates read barriers. Our design is premised on the availability of a sufficient degree of concurrency to stall operations that would otherwise necessitate the copy. Stalled actions are deferred until the next local collection, avoiding exposing forwarding pointers to the mutator. In certain important cases, procrastination is unnecessary -- lightweight runtime techniques can sometimes be used to allow objects to be eagerly copied when their set of incoming references is known, or when it can be determined that having multiple copies would not violate program semantics. We evaluate our techniques on 3 platforms: a 16-core AMD64 machine, a 48-core Intel SCC, and an 864-core Azul Vega 3. Experimental results over a range of parallel benchmarks indicate that our approach leads to notable performance gains (20 - 32% on average) without incurring any additional complexity.

Dynamic Pointer Forwarding Scheme for HMIPv6 Networks

PDF HTML阅读 XML下载 导出引用 引用提醒 面向分层移动IPv6 网络的动态指针推进机制 DOI: 10.3724/SP.J.1001.2011.03743 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(90604003, 60603067) Dynamic Pointer Forwarding Scheme for HMIPv6 Networks Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:基于指针推进机制的分层移动IPv6 方案因未考虑移动锚点管理域的影响,导致较高的注册和报文分发开销.提出一种面向分层移动IPv6 网络的动态指针推进机制(dynamic pointer forwarding scheme for HMIPv6 networks,简称DPF-HMIPv6),移动节点可根据所选移动锚点的管理域大小,动态调整指针推进机制.若所选移动锚点的管理域大于特定阈值,则移动节点通过在接入路由器间构建指针链来避免频繁地向移动锚点注册;若所选移动锚点的管理域小于阈值,则移动节点通过在移动锚点间构建指针链来避免频繁地向家乡代理注册.数值分析和仿真实验的结果表明,该方案能够有效解决现有方案存在的问题,显著降低分层移动IPv6 网络的开销. Abstract:The recent pointer forwarding schemes for HMIPv6, without consideration of MAP’s (mobile anchor point) coverage, may lead to high registration and packet delivery costs. A dynamic pointer forwarding scheme for HMIPv6 networks (DPF-HMIPv6) is proposed in this paper. The scheme allows mobile nodes to execute pointer forwarding schemes, dynamically, in accordance with MAP’s coverage. The pointer forwarding scheme, based on the access router, is used on the condition that mobile node chooses an MAP with a coverage larger than a threshold to avoid frequent registration with MAP. Otherwise, the pointer forwarding scheme, based on MAP, is executed to avoid frequent registration with HA. The numerical simulation results show that this scheme settles the problems better than existing schemes and markedly reduces the cost of HMIPv6 networks. 参考文献 相似文献 引证文献

Design and Performance Analysis of Mobility Management Schemes Based on Pointer Forwarding for Wireless Mesh Networks

We propose efficient mobility management schemes based on pointer forwarding for wireless mesh networks (WMNs) with the objective to reduce the overall network traffic incurred by mobility management and packet delivery. The proposed schemes are per-user-based, i.e., the optimal threshold of the forwarding chain length that minimizes the overall network traffic is dynamically determined for each individual mobile user, based on the user's specific mobility and service patterns. We develop analytical models based on stochastic Petri nets to evaluate the performance of the proposed schemes. We demonstrate that there exists an optimal threshold of the forwarding chain length, given a set of parameters characterizing the specific mobility and service patterns of a mobile user. We also demonstrate that our schemes yield significantly better performance than schemes that apply a static threshold to all mobile users. A comparative analysis shows that our pointer forwarding schemes outperform routing-based mobility management protocols for WMNs, especially for mobile Internet applications characterized by large traffic asymmetry for which the downlink packet arrival rate is much higher than the uplink packet arrival rate.

A Profile-Based Two-Level Pointer Forwarding Cache Scheme for Reducing Location Management Cost in Wireless Mobile Networks

this paper we propose an efficient location management strategy called the profile#based two#level pointer forwarding cache scheme to improve the overall performance of the wireless mobile networks. It uses the twolevel pointer for location update and the profilebased cache for call delivery. Loca tion update for each Mobile Terminal (MT) is managed by the nearby Visitor Location Register (VLR) until it crosses the threshold of the number movements between Registration Areas (RAs). This reduces the frequency of accessing the remote Home Location Register (HLR) which eventually minimizes the location update cost by distributing its work. On the other hand, a profile of the MT's calling pattern is maintained in HLR and it is copied in the VLR caches from where majority of the calls are generated. These caches are searched first to find out the called MT's location in order to deliver a call. This delivery cost will be reduced if the location information is found in the caches since it does not have to access the remote HLR for searching the location information. The analytical modeling and numerical results show that the proposed method outperforms all other previous methods in terms of network signaling traffic load irrespective of the MTs' mobility and calling pattern. Switching Center (MSC) and the MTs are wirelesscon nected to these BTS. Sometimes the VLR may colocate with the MSC and a group of RAs are interfaced with the Local Signaling Transfer Point (LSTP) following the HLR. An HLR is the centralized database that contains the records of all MTs' profiles together with the location information for the entire network. Similarly, each VLR stores replications of the user profiles of the subscribers currently residing in its corresponding RA. However, there may exist one or more HLRs in the network depending on its configuration. Figure 1 shows the architecture of the wireless mobile networks.

Improved replication-based incremental garbage collection for embedded systems

We have developed an incremental compacting garbage collector for embedded Java systems. The collector divides the heap into equal sized pages and uses the segregated free lists for fast allocation. Collectors that have such a heap layout have a problem of fragmentation in allocating objects larger than the page size. We solve this problem by using the replication-based incremental compaction. The compactor evacuates all objects in one area, the evacuation area, of the heap, thereby creating a large chunk of free space. We developed an algorithm for choosing the evacuation area that effectively cures fragmentation. The compactor does not use any read-barriers. Instead, it uses a technique similar to the replication-based incremental copying collection. This needs forwarding pointers for all evacuated objects. Rather than introducing an extra field for each object, we use a hash table to store forwarding pointers. Evaluation of this garbage collector implemented in Sun's J2ME Java Virtual Machine showed that all the benchmarks used were able to run without memory starvation using the heap sizes of only 151%-286% of the maximum amount of live data plus 8 KB of the hash table. Experiments on a desktop computer, though it is not a platform for embedded systems, showed that the maximum pause time was shorter than 200 μs, which was comparable to that of our implementation of the snapshot-at-the-beginning collector without compaction. On an ARM processor, the runtime overhead was 1%-16% with 8.0% on average compared to the mark-sweep collector.