백상헌 교수

With the advance of wireless local area network (WLAN) technology, handoff support has become one of the most important issues in IEEE 802.11 WLANs. However, the current IEEE 802.11 specification does not provide the fast handoff required for real-time multimedia applications. To support fast handoff in IEEE 802.11 networks, a number of fast-handoff schemes have been proposed in the literature. In this article we review these fast-handoff schemes and analyze their advantages and disadvantages qu

Recently, wireless LAN systems have been widely deployed for public mobile Internet services. Public wireless LAN systems can provide high speed Internet connectivity using portable devices such as laptop computers, personal digital assistants (PDAs), etc. In public wireless LAN systems, reliable user authentication and mobility support are essential issues. However, re-authentication during handoff procedures causes long handoff latency and this affects the quality of service in real-time multi

this paper, we proposed a fast Inter-AP handoff scheme based on a predictive authentication method. In our scheme, a mobile host entering the area covered by an AP, performs authentication procedures for multiple APs, rather than just the current AP. These multiple APs are selected using a Frequent Handoff Region (FHR) selection algorithm, which takes into account users' mobility patterns, service classes, etc. Since a mobile host is registered and authenticated for an FHR in advance, h

SUMMARY Next-generation wireless/mobile networks will be IPbased cellular networks integrating Internet with the existing cellular networks. Recently, Hierarchical Mobile IPv6 (HMIPv6) was proposed by the Internet Engineering Task Force (IETF) for efficient mobility management. HMIPv6 reduces the amount of signaling and improves the performance of MIPv6 in terms of handoff latency. Although HMIPv6 is an efficient scheme, the performance of wireless networks is highly dependent on various system

With the popularity of portable devices, public Internet access service using wireless LAN has started in many countries. In the public wireless LAN network, since re-authentication latency during handoff affects the service quality of multimedia applications, minimizing authentication latency is very important in order to support real-time multimedia applications on the wireless IP network. In this paper, we proposed a fast handoff scheme using the predictive authentication method based on IEEE

Mobility support is one of the most challenging issues in IEEE 802.11 networks. In the proactive neighbor caching (PNC) scheme, when a mobile host is connected to an access point (AP), its context (e.g. security association or QoS information) is propagated in advance to all of the AP's neighbors to reduce handoff processing time. In this paper, we propose a selective neighbor caching (SNC) scheme, which propagates a mobile host's context only to the selected neighbor APs considering handoff pat

By introducing a mobility anchor point (MAP), Hierarchical Mobile IPv6 (HMIP6) reduces the signaling overhead and handoff latency associated with Mobile IPv6. However, if a mobile node (MN)'s session activity is high and its mobility is relatively low, HMIPv6 may degrade end-to-end data throughput due to the additional packet tunneling at the MAP. In this paper, we propose an adaptive route optimization (ARO) scheme to improve the throughput performance in HMIPv6 networks. Depending on the measu

The network mobility (NEMO) basic support protocol provides collective mobility for a group of nodes in vehicular area networks. Since the NEMO basic support protocol always performs the same operations, regardless of a mobile network's characteristics, it cannot achieve optimal performance. We propose an adaptive NEMO support protocol based on hierarchical mobile IPv6. The proposed protocol jointly optimizes binding update (BU) traffic and tunneling overhead by employing the adaptive BU strateg

In this article we study two representative mobility management schemes for mobile hotspots with heterogeneous multihop wireless links: the NEMO basic support protocol at the network layer and the SIP-based network mobility support protocol at the application layer. We evaluate their salient features and quantify their handoff latency. It is shown that the SIP-based network mobility support protocol can easily be deployed and reduce the tunneling overhead incurred in the NEMO basic support proto

Next-generation wireless/mobile networks will be IP-based cellular networks integrating Internet with the existing cellular networks. Recently, hierarchical mobile IPv6 (HMIPv6) was proposed by the Internet engineering task force (IETF) for efficient mobility management. HMIPv6 reduces the amount of signaling and improves the performance of MIPv6 in terms of handover latency. Although HMIPv6 is an efficient scheme, the performance of wireless networks is highly dependent on various system parame

In-band network telemetry (INT) is an emerging network monitoring framework based on a protocol-independent packet processor (P4). Network devices can be programmed with a domain-specific language to embed switch-internal states into data packets as they traverse through networks. However, the current P4-based INT does not support a sampling; thus, INT headers should be augmented for all incoming packets, which will incur high overhead in a large-scale network. In this paper, we propose a flexib

Mobility support in IEEE 802.11 networks is a challenging issue. Recently, a new scheme, called proactive neighbor caching (PNC), was proposed and adopted as an IEEE standard. The PNC scheme introduces a neighbor graph, which dynamically captures the mobility topology of a wireless network for pre-positioning the context of a mobile host (MH). However, the PNC scheme may result in a significant signaling overhead because the MH's context is propagated to all neighbor access points (APs). We prop