Hun-Jung Lim

The Bias Routing Tree Avoiding Technique for Hierarchical Routing Protocol over 6LoWPAN

6LoWPAN is a low-power wireless personal area network and a technique to apply TCP/IP stack to sensor networks. By installing IPv6 stack to the sensor node, the sensor networks have interoperability with the external IPv6 network. To solve the 6LoWPAN’s restrictions, IETF working group recently published problems, IPv6 header compression, and routing mechanism requirement documents through their study. Among the suggested routing mechanisms, there is a hierarchical routing protocol designed to establish a hierarchical tree with parent and child nodes to transmit packets. However, the authors design only the address allocation mechanism and the routing mechanism. In our paper, we describe one of the hierarchical routing protocol’s problems and suggest a mechanism to avoid the bias routing tree that could happen in the condition child nodes don’t attach to parents nodes evenly. The simulation result shows that the four nodes are suitable for communication.

A Scheme to reduce the handoff latency using mSCTP in Fast Mobile IPv6

As improvement of wireless and mobile technologies, mobile devices such as laptops and PDAs are widely used. To support the mobility of such devices, mobile IPv6 (MIPv6) was proposed. In addition, fast mobile IPv6 (FMIPv6) and hierarchical mobile IPv6 (HMIPv6) was proposed for the seamless handoff. On the other hands, in transport layer, mobile stream control transport protocol (mSCTP) was proposed for the mobility support. The dynamic address resolution (DAR) signal in mSCTP provides an IP configuration to the Mobile Node (MN). With the DAR, the MN can change its IP address dynamically without connectionless. In the handoff procedure of FMIPv6, access routers (ARs) make the tunnel between them to reduce packet loss during link layer handoff. However, this scheme causes ARs packet forwarding process and buffering overhead. In addition, due to exchange some message to make the tunnel, a few handoff signaling costs and latencies are occurred in FMIPv6. Thus, in this paper, we propose the integrated handoff scheme using mSCTP in FMIPv6 to solve such problems. In the proposed scheme, the tunnel is not created anymore, because the MN uses the DAR signals to the handoff. Therefore, the proposed scheme removes tunneling overhead, a few signaling costs, and latencies. Moreover, the MN not executes a binding update (BU) procedure with the correspondent node (CN) after link layer handoff, because the MN registers a new IP address to CN in advance. The result of performance evaluation show that the proposed scheme reduces handoff latency about 54% and signaling cost about 45% compared to FMIPv6.

MANET ID : Improvement on Group Communications and ZRP

A Mobile Ad hoc NETwork (MANET) could establish a communication in network infrastructure-less places. In an ad hoc network, a basic IPv6 address auto-configuration mechanism has an address allocation problem. A number of address allocation mechanisms have been suggested. However, mobile node(MN)s have high mobility and random address. Therefore, they do not guarantee fixed and shared network prefix. To guarantee equality of network prefix among connected MNs, we propose a MANET identifier (MANET.ID). This scheme allows MNs to share the same MANET_ID using a creation & negotiation phase. By sharing an equal MANET_ID, we achieve a number of enhancements for existing ad hoc network technologies: Enhanced group communication, avoiding duplicate address detection storms, and enhanced zone routing protocol (ZRP).

A survey on privacy problems and solutions for VANET based on network model

For a long term of vehicle communication research, now VANET is in a stage of implementation. However, most of VANET researches focus on message transmission. Vehicle is extremely personal device; therefore personal information, so called privacy has to be protected. In this paper, we analyze identity and location privacy threatening factors, problems, and solutions based on network model. To analyze solutions effectiveness, we define four attack models: External attack, Internal attack, Correlational attack, and Relational attack. According to our research, most of the solutions use pseudonym identity or address changing scheme to protect identity privacy. Also, solutions are weak to or do not consider the relational attack. We analyze this is due the meet the network models transparency design goal and protect vehicles real identity even revealing the vehicles location. The result of this paper could guide a way to design a privacy preserve solution and present a trend of existing solutions.

Privacy Treat Factors for VANET in Network Layer

For a long term of vehicle communication research, now, VANET is in a stage of implementation. However, most of the VANET researches focus on message transmission, address allocation, and secure communication. Vehicle is extremely personal device; therefore personal information, so called privacy has to be protected. There are three kinds of privacy including identity privacy, location privacy, and data privacy. Data privacy is easily achieved by encryption method in application layer. In this paper, we analysis the identity and location privacy treat factor, problem, and solutions in network layer which is the most important layer for end-to-end data transmission. Our analysis includes four IP families: IPv4, IPv6, Mobile IPv6, and Proxy Mobile IPv6. The result of this paper could guide a way to design a privacy protection solution and present existing solution’s trend.