• Journal of Korea Multimedia Society
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• v.12 no.11
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• pp.1593-1608
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• 2009

If a certain relay node in multi-hop wireless networks might become a malicious node that does not cooperate with other nodes or a selfish node, network throughput will be dramatically decreased. Most of existing ad hoc routing protocols assuming that the nodes will fully cooperate with other nodes do not resolve the problem of network performance degradation due to malicious and selfish nodes. This paper presents the CARE (Cooperative Ad hoc routing protocol based REputation) scheme incorporating the reputation management that can achieve a multi-hop wireless network with high throughput performance. The proposed scheme provides the horizontal cross-layer approach which can identify misbehaving malicious, selfish nodes dropped out of the hop-by-hop based packet processing in the network and then set up an optimal packet routing path that will detour misbehaving nodes. And the vertical cross-layer approach contained in the CARE scheme attempts to improve the quality of routing paths by exploiting the quality of link information received from the MAC layer. Besides, it provides high TCP throughput by exploiting the reputation values of nodes acquired from the network layer into the transport layer. A case study on experiments and simulations shows that the CARE scheme incorporating vertical and horizontal cross-layer approaches yields better performance in terms of the low rate of packet loss, fast average packet delivery time, and high TCP throughput between end-to-end nodes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3A
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• pp.287-295
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• 2010

In wireless sensor networks(WSNs), the studies that support sink mobility without global position information exploit a Backbone-based Virtual Infrastructure (BVI) which considers one-hop clusters and a backbone-based tree. Since the clusters of a sink and a source node are connected via flooding into the infrastructure, it causes high routing cost. Although the network could reduce the number of clusters via multi-level clusters, if the source nodes exist at nearest clusters from the cluster attached by the sink and they are in different branches of the tree, the data should be delivered via detour paths on the tree. Therefore, to reduce the number of clusters, we propose a novel multi-hop cluster based communication protocol supporting sink mobility without global position information. We exploit a rendezvous cluster head for sink location service and data dissemination but the proposed protocol effectively reduces data detour via comparing cluster hops from the source. Simulation shows that the proposed protocol is superior to the existing protocols in terms of the data delivery hop counts.

• The KIPS Transactions:PartA
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• v.8A no.2
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• pp.99-106
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• 2001

In this paper, we study fault-tolerant multicasting in multicomputers based on multistage interconnection networks (MIN’s). In addition to one-to-one routing among processing nodes, efficient multicasting has an important effect on the performance of multicomputers. This paper presents a multicasting algorithm to tolerate faulty switching elements. The proposed algorithm uses the cube encoding scheme to represent multicast destinations in MIN, and is based on a recursive scheme in order to bypass faults. This algorithm can route any multicast message to its own destinations in only two passes through the MIN containing several faulty switching elements. Moreover, we prove the correctness of our algorithm by exploiting well-known nonblocking property of MIN.

• Journal of KIISE:Information Networking
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• v.30 no.2
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• pp.252-259
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• 2003

In the case of link congestion, most of the existing ad-hoc routing protocols like AODV and DSR do not try to discover a new route if there is no change in the network topology. Hence, with low mobility, traffic may get concentrated on some specific nodes. Since mobile devices have low battery power and low computing capability, traffic concentration on a specific node is not a desirable phenomenon. Therefore, in this paper, we propose a new protocol called SLAP (Simple Load-balancing Ad-hoc routing Protocol) which resolves the traffic concentration problem by letting each node check its own load situation and give up its role as a packet forwarder gracefully in the case of high traffic load. We compare the performance of SLAP with that of AODV and DSR in terms of the forwarding traffic distribution.

• Journal of KIISE:Information Networking
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• v.36 no.1
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• pp.12-23
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• 2009

Sensor networks deployed in battlefields to support military operations or deployed in natural habitats to monitor the rare wildlifes must take account of protection of the location of valuable assets(i.e., soldiers or wildlifes) from an adversary or malicious tracing as well as the security of messages in transit. In this paper we propose a routing protocol GSLP(GPSR-based Source-Location Privacy) that is capable of enhancing the location privacy of an active source node(i.e., message-originating node) in the presence of multiple dormant sources(i.e., nodes lying nearby an asset whose location needs to be secured). Extended is a simple, yet scalable, routing scheme GPSR(greedy perimeter stateless routing) to select randomly a next-hop node with a certain probability for randomizing paths and to perform perimeter routing for detouring dormant sources so that the privacy strength of the active source, defined as safety period, keeps enhanced. The simulation results obtained by increasing the number of dormant sources up to 1.0% of the total number of nodes show that GSLP yields increased and nearly invariant safety periods, while those of PR-SP(Phantom Routing, Single Path), a notable existing protocol for source-location privacy, rapidly drop off as the number of dormant sources increases. It turns out that delivery latencies of GSLP are roughly less than two-fold of the shortest path length between the active source and the destination.

• Journal of KIISE
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• v.42 no.8
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• pp.1057-1064
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• 2015

The tactical network is system based on wireless networking technologies that ties together surveillance reconnaissance systems, precision strike systems and command and control systems. Several alternative paths exist in the network because it is connected as a grid to improve its survivability. In addition, the network topology changes frequently as forces and combatants change their network access points while conducting operations. However, most Internet routing standards have been designed for use in stable backbone networks. Therefore, tactical networks may exhibit a deterioration in performance when these standards are implemented. In this paper, we propose Priority based Multi-Path routing with Local Optimization(PMPLO) for a tactical backbone network. The PMPLO separately manages the global and local metrics. The global metric propagates to other routers through the use of a routing protocol, and it is used for a multi-path configuration that is guaranteed to be loop free. The local metric reflects the link utilization that is used to find an alternate path when congestion occurs, and it is managed internally only within each router. It also produces traffic that has a high priority privilege when choosing the optimal path. Finally, we conducted a simulation to verify that the PMPLO can effectively distribute the user traffic among available routers.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.241-244
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• 2004

In recent years, WDM networks have received much attention as the Internet backbone networks because of the explosive growth of the Internet IP-based traffic. The Optical Burst Switching (OBS) has been proposed as an effective optical switching technology in the WDM networks. OBS has the advantages in 1) the high usage rate of the bandwidth, and 2) no necessity of optical buffer. However OBS has the burst-contention problem in the networks. The deflection routing is proposed as one of means to solve this problem. In this paper, we propose a new routing method of using deflection routing. In addition. we propose a QoS/CoS control method using a new routing algorithm. Finally, we show the variety of the proposed methods by computer simulations.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.3
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• pp.157-167
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• 2010

One of the most famous proactive routing protocols, DSDV (Destination -Sequenced Distance-Vector), is based on the minimum hop count. This paper suggests BIMP(Bypass Information Multi-Path) DSDV routing protocol that this protocol could route reliably as it can take the information of the bypass for the solution of the problem on EHMP DSDV. In this paper, the protocol checks throughput, packet delivery delay, packet delivery ratio, number of management messages, packet transmit finish time, etc on the traffic compared to DSDV, HMP DSDV, and EHMP DSDV protocols.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.259-261
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• 2001

본 논문에서는 ATM 스위칭 시스템에서 사용되는 다단계 상호연결망(MIN)에서의 고장 허용 멀티캐스팅 알고리즘을 제안하고 그 신뢰도에 대해 분석한다. 멀티미디어 통신 서비스를 효율적으로 제공하기 위해서, 멀티캐스트는 ATM 스위칭 시스템에서 중요한 기능 중 하나이다. 또한, 고장에 취약한 MIN에서 고장 허용하는 것을 필수적인 요소이다. 제안된 알고리즘은 MIN에서 다수의 스위칭 소자의 고장을 허용하며, 멀티캐스트 목적지들을 표현하기 위해 큐브 부호화 방식을 사용한다. 이 알고리즘은 고장난 MIN에서 임의의 멀티캐스트 패킷을 두 번 순환시킴으로써 고장을 우회하면서 그 패킷의 목적지들로 라우팅을 한다. 그리고, 시스템의 신뢰도 측면에서 알고리즘의 고장 허용 능력을 기존의 알고리즘과 비교하여 분석한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.5
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• pp.281-290
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• 2014

The real-time data dissemination schemes exploit the spatiotemporal commuication approach which forwards data at the delivery speed calculated with the desired time deadline and the end-to-end distance in wireless sensor networks (WSNs). In practical environments, however, the performance of the real-time data dissemination might be degraded by additional and inevitable delay due to some holes. Namely, the holes lengthen the data delivery path and the spatiotemporal approach could not estimate a distance of the data delivery path. To deal with this, we propose A Hole Self-Organization Real-time Routing Protocol for Irregular Wireless Sensor Networks. In proposed protocol, nodes around holes could detect them at deploying phase. A hole is represented as a circle with center point and radius. This hole information is processed and provided as a form of location service. When a source queries a destination location, location provider replies certain points for avoiding holes as well as destination location. Thus, the source could set desired speed toward the destination via the points. Performance evaluation shows that provides better real-time service in practical environments.