• Journal of the Korea Society of Computer and Information
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• v.9 no.3
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• pp.177-182
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• 2004

The existing group key management architectures applied to a small scale routing protocols may have many overheads with key distribution. Therefore this paper proposes a group key management protocol in PIM-SM multicast group communication. This method divide multicast groups with RP, and subgroup key managers are established in each RP and can be transmitted groups keys. And this does not have needs of the data translation and the new key distribution for path change. This does not have needs of the data translation and the new key distribution for path change, so the data transmission time can be reduced.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.95-101
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• 2005

In this paper, some performance characteristics of multimedia traffic for mobile ad-hoc networks is studied with simulations. Synthetic streaming video is considered as the multimedia traffic for MPEG-coded video in the simulation. The synthetic video stream is generated with a video stream generation algorithm. The algorithm generate VBR traffics for MPEG video streams with special predefined GOP(group of pictures) patterns that is consisted of a sequence of I(intra-coded), P(predicted-coded) and B(bidirectional-coded) frames. The synthetic VBR streams is transmitted through UDP protocol with on-demand mobile ad-hoc network routing protocols like as AODV and DSR. And performances for video streams through mobile ad-hoc networks is evaluated, the throughputs is compared between data and video traffics.

• Journal of information and communication convergence engineering
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• v.9 no.2
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• pp.244-250
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• 2011

Gossip is a well-known protocol which was proposed to implement broadcast service with a high reliability in an arbitrarily connected network of sensor nodes. The probabilistic techniques employed in gossip have been used to address many challenges which are caused by flooding in wireless sensor networks (WSNs). However, very little work has yet been done on real-time wireless sensor networks which require not only highly reliable packets reception but also strict time constraint of each packet. Moreover, the unique energy constraining feature of sensor makes existing solutions unsuitable. Combined with unreliable links, redundant messages overhead in real-time wireless sensor networks is a new challenging issue. In this paper, we introduce a Reliable Gossip Zone, a novel fine-tailored mechanism for real-time wireless sensor networks with unreliable wireless links and low packet redundancy. The key idea is the proposed forwarding probability algorithm, which makes forwarding decisions after the realtime flooding zone is set. Evaluation shows that as an oracle broadcast service design, our mechanism achieves significantly less message overhead than traditional flooding and gossip protocols.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5B
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• pp.762-770
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• 2010

The researches about energy efficieny of wireless sensor MAC protocol is an issue in present days. Therefore, MAC and routing protocols for reducing energy consumption at sensor nodes is needed. In this study, a low-power MAC protocol for sensor network is proposed, which in based on X-MAC by exploiting virtual synchronization. The virtual synchronization technique lets senders postpone packet transmission until receivers' wake-up time, so that senders transmit only one or two short preambles. Using NS-2, a proposed MAC protocol improve the energy efficiency by 10% compared with the X-MAC protocol.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.12
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• pp.3086-3097
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• 1996

Generally, the performance of the computer network may differ according to various parameters like routing, bandwidth and timers. Since the network system requirements may widely very according to specific application, computer network must be tailored at tailored at the design starge by selection of appropriate protocols and assignment of degfault parameter. However, since the condition under which a network actually operates may change from that considered at the design stage, control and managment action are required to adjust the network parameter so that the perforance of network is satisfied.

• Convergence Security Journal
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• v.8 no.1
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• pp.19-26
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• 2008

In wireless sensor networks, an adversary can launch the wormhole attacks, where a malicious node captures packets at one location and tunnels them to a colluding node, which retransmits them locally. The wormhole attacks are very dangerous against routing protocols since she might launch these attacks during neighbor discovery phase. A strategic placement of a wormhole can result in a significant breakdown in communication across the network. This paper presents a compromise-resilient tunneled packet filtering method for sensor networks. The proposed method can detect a tunneled message with hop count alteration by a comparison between the hop count of the message and one of the encrypted hop counts attached in the message. Since the proposed method limits the amount of security information assigned to each node, the impact of wormhole attacks using compromised nodes can be reduced.

• ETRI Journal
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• v.42 no.3
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• pp.351-365
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• 2020

Directional sensor networks (DSNs) can significantly improve the performance of a network by employing energy efficient communication protocols. Neighbor discovery is a vital part of medium access control (MAC) and routing protocol, which influences the establishment of communication between neighboring nodes. Neighbor discovery is a challenging task in DSNs due to the limited coverage provided by directional antennas. Furthermore, in these networks, communication can only take place when the beams of the directional antennas are pointed toward each other. In this article, we propose a novel multiple token-based neighbor discovery (MuND) protocol, in which multiple tokens are transmitted based on an area exploration algorithm. The performance of the protocol is evaluated using the Cooja simulator. The simulation results reveal that the proposed MuND protocol achieves lower neighbor discovery latency, with a 100% neighbor discovery ratio, and has a relatively low communication overhead and low energy consumption.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.148-155
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• 2007

The routing optimization mode, which Mobile IPv6 provides for the direct communication between a mobile node and its correspond node, introduces various security threats, thus causing several protocols to be proposed for the secure binding update procedure. In particular, the Kang-Park protocol, which Kang and Park presented in 2005, achieves the optimized cryptographic operations and the strong security, while based on its unique security proxy structure. In spite of such advantages, it has some drawbacks in terms of security and efficiency. This paper improves the Kang-Park protocol through the strong CoA validation and early binding update methods. Also, we show that the improved protocol is better than others.

• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.138-147
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• 2003

There are some problems of current internet protocols to support the mobility of terminal in wireless environments. The mobile IP has come out to solve these problems, but there exists some problems like triangle routing, the need of each host's home address and the management of tunneling. Also. real-time multimedia traffics require fast hand-off, low latency and the utilization ratio of high bandwidth. SIP can support the mobility of wireless terminal and is widely accepted as the protocol which can support multimedia service and call setup in next generation network. In this paper, the framework of SIP system will be designed and implemented to support the mobility of wireless terminal by using JAIN API which follow the standards of next generation network and this system matches the standards of next generation network.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.12
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• pp.5150-5169
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• 2015

Mobile Ad hoc NETworks (MANETs) are the best choice when mobility, scalability, and decentralized network infrastructure are needed. Because of critical mission applications of MANETs, network security is the vital requirement. Most routing protocols in MANETs assume that every node in the network is trustworthy. However, due to the open medium, the wide distribution, and the lack of nodes' physical protection, attackers can easily compromise MANETs by inserting misbehaving nodes into the network that make blackhole attacks. Previous research to detect the misbehaving nodes in MANETs used the overhearing methods, or additional ACKnowledgement (ACK) packets to confirm the reception of data packets. In this paper a special lightweight acknowledgement-based method is developed that, contrary to existing methods, it uses ACK packets of MAC layer instead of adding new ACK packets to the network layer for confirmations. In fact, this novel method, named PIGACK, uses ACK packets of MAC 802.11 to piggyback confirmations from a receiver to a sender in the same transmission duration that the sender sends a data packet to the receiver. Analytical and simulation results show that the proposed method considerably decreases the network overhead and increases the packet delivery ratio compared to the well-known method (2ACK).