Hae-won Jung

New Approach for Reducing DAD delay using Link Layer Assistance in Mobile IPv6

There have been a lot of research and investigation to improve handover latency of mobile IPv6 (MIPv6). The handover latency is one of the most important factors because performance of TCP flows as well as realtime traffic degrades sharply as the latency increases. The MIPv6 handover process consists of movement detection, duplicate address detection (DAD), and binding update. Among the three components, DAD has been identified as the most critical factor. In this paper, we introduce novel schemes to reduce the DAD delay. By utilizing tentative address that an access router provides, a mobile node pre-determines its care-of-address before L2 handover such that the DAD period can be greatly reduced. We also devise a mechanism that reduces the messaging overhead via link layer assistances. Extensive performance analyses show that the proposed scheme significantly enhances the performance of MIPv6.

An Enhanced Fast Handover Scheme with Temporal Reuse of CoAs and PBP in IPv6-Based Mobile Networks

With the rapid development of wireless technologies, the need to support moving hosts of IPv6-based mobile networks in ubiquitous environment is growing. So the demand for delay sensitive applications, such as multimedia stream, VoIP, that requires increasingly seamless handover. Various well-known approaches to optimize the handover latency have been proposed in the literature: MlPv6,FMIPv6,HMIPv6 and F-HMIPv6. However, these approaches are inefficient in handover delay, packet loss, out-of order problem, dependency of exact predictive information, a sudden disruption of the link and so on. In this paper, we propose an enhanced fast handover scheme with temporal reuse of care of addresses (CoAs) and packet buffering point (PBP) in IPv6-based mobile networks. The proposal reduces the handover latency, handover initiation time through the temporal reuse of CoAs as tentative addresses already proved unique by other mobile node (MN) using DAD (duplicate address detection). It also solves the packet loss and out of order problem by PBP which is the above router between previous access router (pAR) and new access router (nAR).

Adaptive Threshold-based Link Status Update Mechanism

The current Internet protocol (IP)-based networks face tremendous requirements such as quality of service (QoS) guarantees, efficient traffic engineering (TE), network scalability, and high network performance, in accordance with the emergence of diverse Internet services. A constraint-based routing path is determined based on network topology and link state information to guarantee QoS. It is necessary for constraint-based routing to disseminate and update link state information. Throughput can be reduced due to processing link state update messages if link update messages are generated excessively. On the other side, route setup requests can be rejected even though there are available routes in case that link state information is not updated appropriately. This paper proposes a new adaptive threshold-based link status update mechanism to reduce the volume of link state update traffic and to provide QoS-guaranteed path. In addition, the performance of the proposed mechanism is evaluated via simulations

Inter-Domain QoS Routing Scheme using Link State Information

In the Internet, in order to guarantee Quality of Service (QoS), all routers have to manage their Link State Databases (LSDBs) and determine a routing path that satisfies service requirements based on the LSDB. In addition, routing protocols have to provide QoS not only in the intra- domain but also in the inter-domain to enable the end to end QoS guarantee. In the intra-domain routing, it is possible that a router manages its LSDB because the link state information is small in a domain. On the other hand, in inter- domain routing, since the amount of the link state information is very large, it is unrealistic to manage the whole link state information. The Border Gateway Protocol (BGP) is the most prominent inter-domain routing protocol in the current internet. However, it is difficult to guarantee the inter-domain QoS using BGP because the BGP is a path- vector based protocol. In this paper, we propose the inter- domain QoS routing schemes that can manage the LSDBs effectively and minimize a waste of the network system resources by Link State Update (LSU) massages. We evaluate the performance of the proposed schemes by simulations. From the results, the proposed schemes can reduce the blocking probability and amount of the link state update with a few link state information.

Capacity Planning with the Statistical Prediction of on-off Flows

A novel approach to describe the relation, in terms of probability, between the gain obtained by multiplexing the traffics in the packet network and the link capacity for guaranteeing the required quality is proposed. A traffic-flow is defined as the on-off stream described with the probability distribution of the on-off lengths. With the statistical on-off flow description, the loads on a link after aggregating traffic flows can be predicted in terms of probability, and the link capacity design based on the probability of supporting the required quality becomes possible. To have statistical model of a flow with small number of data, an interpolation method is suggested. To find a congestion point with given link capacity and traffic flows, a calculation method to estimate the expected link reservation with traffic flows and the congestion probability is proposed

Optimizing Hash Table Structure of Flow Exporting Software

Traffic measurement is required to protect network from abnormal traffic that is created by attacking or computer virus. Traffic measurement and flow information exporting method have being standardized and partially introduced. But traffic measurement devices and flow exporting software have still too low performance to collect all flows. Recently, traffic grows rapidly and various flow by emerging service to increase cost of traffic measurement. More efficient traffic measurement and flow exporting device is needed

Signaling for traffic engineering with QoS guarantee in IP environment

The advanced information technology (IT) will promote the transformation of communities the world over into an information society and a knowledge-based economy in the next generation. During the past years, the explosive growth of the Internets popularity has brought a great number of changes in the telecommunications area. The current Internet Protocol (IP)-based networks face tremendous requirements such as quality of service (QoS) guarantees, efficient traffic engineering (TE), network scalability, and high network performance, in accordance with the emergence of diverse Internet services. The main focus of this paper is on the evaluation of traffic engineering mechanism supporting QoS in an IP environment. It allows packet routing to be separated from packet forwarding, so that it provides explicit routing and traffic engineering. QoS-based signaling allows requirements of QoS guarantees and traffic engineering to be mapped onto a traffic forwarding path and traffic handling mechanisms, and permits Internet service providers (ISPs) to engineer traffic efficiently so that the utilization of network resources is enhanced and profits may be increased

Link State Update Algorithm considering Traffic Variation

Routers determine a routing path considering network topology and link state information for guaranteeing quality of service (QoS). Therefore, it is important that routers should know link state information so as to calculate a routing path. However, if routers generate link state update messages inordinately, their router performance may be reduced due to the processing burden of link state update messages. On the other side, in case that link state information is not updated appropriately, route setup requests can be rejected even though there are available routes. In this paper, we propose an algorithm to improve router performance and evaluate the proposed algorithm performance as compared with conventional algorithm by simulations.

Method to Provide Host Mobility and Handover Based on Distributed Proxy

Demand for wireless data service glows faster in mobile network. In all-IP base network expected to be introduced, the mobile IPv6 (MIPv6) appeared to provide mobility. With fast handover and optimization of the link layer (L2), MIPv6 goes faster. But MIPv6 does not provide sufficient handover speed and it charges the burden of calculation to compact mobile nodes. In order to reduce the disadvantage of MIPv6, the network-based localized mobility management (NetLMM) method is standardized. In this paper, we show the method which is similar with NetLMM. By eliminating some communication procedure, we can reduce handover time.

Design and Evaluation of Redundant IPC Network Adequate for an Edge Router

In a high-capacity router, with both a single routing processor (RP) and multiple interface cards each equipped with multiple network processors (NPs), it is very important to easily scale its capacity and reliably for the transfer of controlling system messages between the RP and the NPs. For these reasons, the control plane used for control messages, such as inter-processor communication (IPC) messages, is separated from the data forwarding plane used for transferring user data. In this paper, we propose and describe the implementation of control plane architecture, called Redundant IPC Network (RIPCN). We also evaluate the performance of the proposed RIPCN. From the evaluation results, when compared with a conventional IPC method, we show that the RIPCN not only provides an effective approach to the high availability of control plane, but also can improve its performance.