Sung Gi Min

Priority-based QoS MAC protocol for wireless sensor networks

The media access control (MAC) protocol in wireless sensor networks provides a periodic listen/sleep state for protection from overhearing and idle listening. However, many scenarios and applications exist in which sensor nodes must send data quickly to destination nodes. This paper proposes the priority-based quality-of-service MAC (PQMAC) protocol for wireless sensor networks. We use data priority levels to differentiate among data transmissions, and propose a MAC protocol based on these levels. This protocol manages scheduling by adaptively controlling network traffic and the priority level. We focused on reducing the latency of the message transmission from the source to the destination. Simulation results showed that PQMAC reduces latency problems in wireless sensor networks while maintaining energy efficiency.

OpenFlow-based Proxy mobile IPv6 over software defined network (SDN)

Software Defined Network (SDN) is widely deployed by using OpenFlow protocol for the implementation of flexible networking. A lot of researches are progressing to adapt OpenFlow to existing network architectures. PMIPv6 is proposed to handle the network-based local mobility using IP tunneling. However, it has some weak points such as IP tunneling overhead and sharing same path for the data and the control planes. In this paper, we propose OpenFlow-based Proxy Mobile IPv6 (PMIPv6) to obtain the advantages of the OpenFlow architecture for PMIPv6 network. The proposed scheme separates the mobility management function from the components of PMIPv6. It preserves the functionalities and messages defined in PMIPv6 but reconstructs components to take the advantages offered by the OpenFlow architecture. The reconstructed components set the flow table of switches located in the path as the controller of OpenFlow. The proposed scheme removes the tunneling to forward user traffic and separates the data and the control planes. OpenFlow-based PMIPv6 offers more flexible deployment architecture.

Implementation and Evaluation of Proxy Mobile IPv6 in NS-3 Network Simulator

With the rapid growth in the number of mobile subscribers and mobile devices, the demand high-speed Internet access is becoming a primary concern in our lives. Not long ago, the most stable and well known solution of IP-based mobility management is Mobile IPv6 (MIPv6). Even if MIPv6 is a well-known mature standard for IPv6 mobility management support, however, it has revealed some problems such as handover latency, packet loss, and signaling overhead. Thus, a new IPv6 mobility management protocol called Proxy Mobile IPv6 (PMIPv6) is being actively standardized by the IETF NETLMM Working Group. Unlike the various host-based protocols such as MIPv6, a network-based approach such as PMIPv6 has salient features and is expected to expedite the real deployment of IP-based mobility management. In this paper, we present an implementation of PMIPv6 in NS-3 network simulator and the evaluation of the simulation for validating.

PMIPv6-based Flow Mobility Simulation in NS-3

Proxy Mobile IPv6 (PMIPv6) is a network-based mobility support protocol and it does not require MNs to be involved in the mobility support signaling. In flow mobility support, although the virtual interface in the MN solved the problems of vertical handover or flow mobility in heterogeneous network, missing procedure of MN-derived flow handover makes flow mobility in PMIPv6 incomplete. In this paper, enhanced flow mobility support is proposed for actualizing and full-covering of the flow mobility support in PMIPv6. Enhanced flow mobility support is based on a virtual interface in the MN. Virtual interface makes all physical interfaces to hide from the network layer and above. Flow Interface Manager is placed at the virtual interface and Flow Binding Manager in the LMA is paired with Flow Interface Manager. They manage the flow bindings and are used to select proper access technology to send packets. Flow mobility procedure begins with three different triggering cases, which are caused by new connection from the MN, the LMAs decision, and request from the MN, respectively. Simulation using NS-3 network simulator is performed to provide clear and practical procedure of enhanced flow mobility support in PMIPv6.

Performance Analysis of Hierarchical Mobile IPv6: Does it Improve Mobile IPv6 in Terms of Handover Speed?

There has been a rapid growth in the need to support mobile nodes in IPv6-based networks. IETF has completed to standardize Mobile IPv6 (MIPv6) and Hierarchical Mobile IPv6 (HMIPv6) for supporting IPv6 mobility. Even though existing literatures have asserted that HMIPv6 generally improves MIPv6 in terms of handover speed, they do not carefully consider the details of the whole handover procedures. In this paper, based on the current IETF standards of both MIPv6 and HMIPv6, we conduct a comprehensive study of all IP-level handover procedures: movement detection, duplicate address detection, and location registration. Based on this study, we provide a mathematical analysis on MIPv6 and HMIPv6 performance in terms of handover speed. From the analysis, we reveal that the average HMIPv6 handover latency is not always lower than the average MIPv6 handover latency. Furthermore, even the intra-domain handover latency of HMIPv6 is not reduced much compared with MIPv6 handover latency. A finding of our analysis is that optimization techniques for movement detection and duplicate address detection are essential to shortening HMIPv6 handover latency and increasing the benefit of HMIPv6.

Smart Buffering for seamless handover in Proxy Mobile IPv6

Proxy Mobile IPv6 (PMIPv6) is proposed as a new network-based mobility protocol and it does not require MNs involving in mobility management. MN can handover relatively faster in PMIPv6 than in Mobile IPv6 (MIPv6) because it actively uses link-layer attachment information and reduces the movement detection time, and eliminates duplicate address detection procedure. However, the current PMIPv6 cannot prevent packet loss during the handover period. We propose the Smart Buffering scheme for seamlessness in PMIPv6. The Smart Buffering scheme prevents packet loss by proactively buffering packets that will be lost in a current serving mobile access gateway (MAG) by harnessing network-side information only. It also performs redundant packet elimination and packet reordering to minimize duplicate packet delivery and disruption of connection-oriented flows. To fetch buffered packets from a previous MAG, a new MAG discovers the previous MAG by using a discovery mechanism without any involvement of an MN. We verified the effectiveness of Smart Buffering via simulation with various parameters. Copyright

Maximizing the lifetime of wireless ad hoc networks using Minimizing the Maximum used Power Routing

In this paper, we present minimizing the maximum used power routing algorithm (MIVIPR) in mobile ad hoc network (MANET). Most previous energy aware routing protocols usually optimize just one optimization criterion, which minimizes the total used energy or evenly distributes power consumption in each node to prevent node from being over exhausted. MMPR achieves two optimization objectives using a single route cost equation, which is based on the similar optimization, minimizing the maximum link utilization in LPF-Based-Re-Routing (LPF-RR), of traffic engineering (TE). MMPR can be implemented by modifying a route selection procedure in well-known routing protocol of MANET. We validate MMPR by performing a simulation based on a modification of DSR, and the simulation results showed improved performance in the maximum used energy and the number of dead nodes by time than the conditional max-min battery routing (CMMBCR).

Distributed Periodic Access Scheme (DPAS) for the Periodic Safety Messages in the IEEE 802.11p WAVE

In WAVE applications, the safety information of neighboring vehicles must be collected as quickly and efficiently as possible. Safety applications broadcast their safety information periodically, but the delivery of the broadcast messages in IEEE 802.11p is unreliable. As the control channel has to share the Sync Interval (SI) with the service channels, access to the control channel by the safety messages is delayed during the Service CHannel Interval(SCHI). All safety messages generated during SCHI are rush to access as soon as the Control CHannel Interval (CCHI) starts. It causes the flash crowd problem for the safety applications. Safety messages, which are generated periodically and their periods overlap with SCHI, always face the latter problem; it causes unfairness among the safety messages. In this paper, a Distributed Periodic Access Scheme (DPAS) is proposed to solve the problem. DPAS uses a hashing function to distribute the access time of the safety messages into CCHI instead of SI. The simulation results show that DPAS drastically reduces the collision of the safety messages in a crowded environment and that choosing a hashing function is very important to reduce the collision in a crowded environment.

A causal message logging protocol for mobile nodes in mobile computing systems

This paper presents a causal message logging protocol with independent checkpointing for mobile nodes with the aim of efficiently handling several constraints of the mobile nodes such as mobility and disconnection, limited life of battery power, small amount of storage and low bandwidth on wireless link. For this purpose, the protocol includes a low-cost failure-free mechanism requiring only locating the mobility agent maintaining the latest checkpoint of each process on an mobile node during its handoff process. This mechanism forces only the latest checkpoint to be maintained on the stable storage while incurring low failure-free overhead. Also, the protocol uses two garbage collection schemes to remove log information of mobile nodes. The first scheme enables each mobile node to autonomously remove useless log information in its storage by piggybacking only some additional information without requiring any extra message and forced checkpoint. The second scheme allows the mobile node to remove a part of log information in its storage if more empty storage space is required after executing the first scheme. It reduces the number of processes to participate in the garbage collection by using the size of the log information of each process. Simulation results show that the two proposed schemes significantly reduce the garbage collection overhead compared with traditional schemes. Additionally, we present an efficient recovery algorithm to avoid frequent stable storage accesses, impose no restriction on the execution of live processes during recovery and ensure consistent recovery in case of being integrated with independent checkpointing.

Fast handover method for mSCTP using FMIPv6

In this paper, we propose the fast handover method in mSCTP using FMIPv6. Using FMIPv6 as handover procedure in mSCTP, the performance of handover can be significantly improved. First, mSCTP can add new network address to the correspondent node quickly as FMIPv6 provides New Care of Address (CoA) without closing connection to current network. Second, mSCTP can determine when it has to change the primary IP address with the trigger from FMIPv6. This trigger indicates that the mobile node has completely joined the network of New Access Router (NAR) and confirms that the MN can receive data through the NAR. We present integrated handover procedures that maximizes the handover performance between mSCTP and FMIPv6. We implement the integration of mSCTP and FMIPv6 in our test bed and verify the operation of suggested handover procedures by analysis of the experimental result.