• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.5
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• pp.2144-2165
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• 2016

In a vehicular ad hoc network, the communication links are unsteady due to the rapidly changing topology, high mobility and traffic density in the urban environment. Most of the existing geographical routing protocols rely on the continuous transmission of beacon messages to update the neighbors' presence, leading to network congestion. Source-based approaches have been proven to be inefficient in the inherently unstable network. To this end, we propose an opportunistic beaconless packet forwarding approach based on a modified handshake mechanism for the urban vehicular environment. The protocol acts differently between intersections and at the intersection to find the next forwarder node toward the destination. The modified handshake mechanism contains link quality, forward progress and directional greedy metrics to determine the best relay node in the network. After designing the protocol, we compared its performance with existing routing protocols. The simulation results show the superior performance of the proposed protocol in terms of packet delay and data delivery ratio in realistic wireless channel conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.703-712
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• 2015

This paper proposes the UIGRP, which can tackle the problem of the network disconnection and packet transmission delay caused by turning vehicles frequently in an urban intersection. The UIGRP was designed as follows. First, it calculates the direction of vehicles using the moving direction of vehicles and the location of a destination. Second, it makes the RSU measure the density of an urban intersection. Third, the TGF Algorithm in the UIGRP decides the data transmission paths by setting as an intermediate node, not only the vehicle that is moving in the direction where a destination node is located, but also the node that has the highest density. The TGF algorithm using a moving direction and density minimizes or removes the occurrence of local maximum problems that the existing Greedy Forwarding algorithm has. Therefore, the simulation result shows that UIGRP decreases the occurrence of local maximum problems by 3 and 1 times, and the packet transmission time by 6.12 and 2.04(ms), and increases the success rate of packet transmission by 15 and 3%, compared to the existing GPSR and GPUR.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.8
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• pp.1780-1784
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• 2015

Traditional IP routing, see only the Destination Address When Forwarding Layer 3 routing and exchange information and Destination-Based Routing Lookup is required for all Hop. Thus, all routers Full Internet routing information, the route information of more than about 120,000 may require. Therefore, the router configuration, which can be dispersed in the environment, the traffic load is required in accordance with this congestion. In this study, a unique characteristic of the Internet in the environment of an existing network Best Effect for QoS guarantee and hardware high speed switching of large multimedia data transmitted using a Labeling for forwarding a packet environment configuration is required. Video Stream Broadcast Transport Labeling rather than in much of the higher performance of the multi-step policy to most of the Video Stream Packet deulim was fixed to Labeling Header Format proposes a method of applying an effective QoS policy to a more simplified policy.

• The KIPS Transactions:PartC
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• v.10C no.1
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• pp.71-76
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• 2003

Internet traffic is getting tremendously heavier due to the exponential growth of the Internet users, the spread of the E-commerce and the network games. High-speed routers for fast packet forwarding are commercially available to satisfy the growing bandwidth. A high-speed router, which has the decentralized multiprocessing architecture for IP and routing functions, consists of host processors, line interfaces and switch fabrics. In this paper, we propose a software architecture tuned for high-speed non-forwarding packet manipulation. IPCMP (Inter-Processor Communication Message Protocol), which is a mechanism for IPC (Inter-Processor Communication), is also proposed and implemented as well. Proposed IPC mechanism results in faster packet-processing rate by 10% as compared to the conventional IPC mechanism using UDP/IP.

• Journal of Korea Multimedia Society
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• v.17 no.10
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• pp.1220-1228
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• 2014

Emergency Warning Service will be the most important service of VANET. Transmission delay is the most important performance criteria of the warning service. Most legacy research takes a way to minimize the packet collision. However those approach has a critical weak point on urban environment where there is a blind area of electric wave. So another issue is required in order to provide enhanced warning message propagation technique to overcome the urban environment problem. In this paper, I proposed an enhanced warning message propagation scheme in the poor electric wave environment as the intersection area. Proposed scheme forwards the warning message to the blind area by enhanced forwarding node selection technique. For efficiency of warning message propagation, I suggest forwarding priority for decision of forwarding node. And the node has a direct mode or redirect mode depending on neighbor nodes. The simulation was carried out to evaluate the performance. The simulation results show that proposed scheme has the superior performance compared to legacy warning message technique.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.889-894
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• 2004

Most ad-hoc routing protocols such as AODV(Ad Hoc On-Demand Distance Vector) and DSR(Dynamic Source Routing) do not try to search for new routes if the network topology does not change. Hence, with low node mobility, traffic may be concentrated on several nodes, which results in long end-to-end delay due to congestion at the nodes. Furthermore, since some specific nodes are continuously used for long duration, their battery power may be rapidly exhausted. Expiration of nodes causes connections traversing the nodes to be disrupted and makes many routing requests be generated at the same time. Therefore, we propose a load balancing approach called Simple Load-balancing Approach (SLA), which resolves the traffic concentration problem by allowing each node to drop RREQ (Route Request Packet) or to give up packet forwarding depending on its own traffic load. Meanwhile, mobile nodes nay deliberately give up forwarding packets to save their own energy. To make nodes volunteer in packet forwarding. we also suggest a payment scheme called Protocol-Independent Fairness Algorithm (PIEA) for packet forwarding. To evaluate the performance of SLA, we compare two cases where AODV employs SLA or not. Simulation results show that SLA can distribute traffic load well and improve performance of entire ad-hoc networks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.6
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• pp.1096-1101
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• 2004

By a tremendous expansion of Internet users, there's a number effects that cause the phenomenon of bottlenecked switching packets from routers. In order to tear down this problem, distributed system is applicable to almost every highly performed router systems. The main processor of distributed system, which manages routing table, commands IPC to delivering the forwarding table line processor that eases functionalities of the router. This makes the system having wired-speed forwarding function based on the hardware so that the performance of the network can be enhanced. Therefore, IPC, which assign a part of router, is necessary to exchange data smoothly and the constitution of IPC using Ethernet is widely adapted as a method for saving investment. In this paper, R-IPC mechanism improve the packet-processing rate over 10% through changed from defect of conventional Ethernet IPC, that is, 2 layer processing to TCP/IP or UDP/ IP into 1 layer processing for efficient packet forwarding.

• Journal of the Korea Society of Computer and Information
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• v.26 no.3
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• pp.69-75
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• 2021

Limitation of the TCP/IP network technology included in the vehicle communication is due to the frequent mobility of the vehicle, the increase in intermittent connection requirements, and the constant presence of the possibility of vehicle hacking. VNDN technology enables the transfer of the name you are looking for using textual information without the need for vehicle identifiers like IP/ID. In addition, intermittent connectivity communication is possible rather than end-to-end connection communication. The data itself is the subject of communication based on name-based forwarding using two types of packets: Interest packet and Data packet. One of the issues to be solved for the realization of infotainment services under the VNDN environment is the traffic explosion caused by data broadcasting. In this paper, we analyze and compare the existing technologies to reduce the data broadcast storm. Through this, we derive and analyze the requirements for presenting the best data mitigation technique for solving the data explosion phenomenon in the VNDN environment. We expect this paper can be utilized as prior knowledge in researching improved forwarding techniques to resolve the data broadcast explosion in connected vehicles over NDN.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6A
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• pp.538-546
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• 2010

This paper presents an overview of position-based routing algorithms. We analyze performances of routing algorithms such as Hybrid Opportunistic Forwarding (HOF), Opportunistic multi-hop routing (ExOR), Location based Geocasting and Forwarding (LGF), and Greedy Forwarding in nearest with forward Progress (GFP) routing algorithms to find the best one in terms of packet error rate and throughput efficiency over effects of fading and noise variance in wireless networks. The analyses in closed form expressions are confirmed by the simulation results, which fully agree to analysis results. Additionally, the simulation results indicate significant differences among algorithms when varying the average SNR or the number of relays.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5442-5463
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• 2016

Designing efficient routing protocols for a wireless sensor network with mobile sinks (mWSN) is a challenging task since the network topology and data paths change frequently as sink nodes move. In this paper, we design a novel lightweight reactive ring based routing protocol called R3, which removes the need of proactively maintaining data paths to mobile sinks as they move in the network. To achieve high packet delivery ratio and low transmission cost, R3 combines ring based forwarding and trail based forwarding together. To support efficient ring based forwarding, we build a ring based structure for a network in a way such that each node in the network can easily obtain its ring ID and virtual angle information. For this purpose, we artificially create a virtual hole in the central area of the network and accordingly find a shortest cycled path enclosing the hole, which serves as base ring and is used for generating the remaining ring based structure. We accordingly present the detailed design description for R3, which only requires each node to keep very limited routing information. We derive the communication overhead by ring based forwarding. Extensive simulation results show that R3 can achieve high routing performance as compared with existing work.