• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.1
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• pp.8-16
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• 2014

In this paper, we propose a fast and scalable flow mobility management scheme based on the flow-based stateful routing for the IP-based mobile networks. The proposed scheme employees the crossover flow routers as mobility anchors to perform the distributed flow-based mobility management of the moving terminals, while aims to reduce the long handoff delay and the processing overhead of the existing IP packet routing. We evaluated the performance of the proposed scheme and verified the superior performance of the proposed scheme by comparing with the results of IP-based mobility management schemes.

• Journal of Communications and Networks
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• v.7 no.3
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• pp.367-376
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• 2005

The smooth handoff supported by the route optimization extension to the mobile IP standard protocol should support a packet buffering mechanism at the base station (BS), in order to reduce the degradation in TCP performance caused by packet losses within mobile network environments. The purpose of packet buffering at the BS is to recover the packets dropped during intersubnetwork handoff by forwarding the packets buffered at the previous BS to the new BS. However, when the mobile host moves to a congested BS within a new foreign subnetwork, the buffered packets forwarded by the previous BS are likely to be dropped. This subsequently causes global synchronization to occur, resulting in the degradation of the wireless link in the congested BS, due to the increased congestion caused by the forwarded burst packets. Thus, in this paper, we propose an implicit priority forwarding (IPF) packet buffering scheme as a solution to this problem within mobile IP based networks. In the proposed IPF method, the previous BS implicitly marks the priority packets being used for inter-subnetwork handoff. Moreover, the proposed modified random early detection (M-RED) buffer at the new congested BS guarantees some degree of reliability to the priority packets. The simulation results show that the proposed IPF packet buffering scheme increases the wireless link utilization and, thus, it enhances the TCP throughput performance in the context of various intersubnetwork handoff cases.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.267-280
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• 2005

In this paper, we implement and verify XMIP integrating IETF Mobile IP and the Explicit Multicast mechanism for a great number of small group multicast communications. U a source node sends Xcast packets explicitly inserting destination nodes into the headers, each Xcast router decides routes and forwards the packets toward each destination node based on unicast routing table without the support of multicast trees. n is a straightforward and simple multicast mechanism just based on a unicast routing table without maintaining multicast states because of the inheritance from the Explicit Multicast mechanism. This research modifies and extends the functionality of IETF Mobile IP's mobility agents, such as HA/FA to HA+/FA+ respectively, considering interworking with Xcast networks. Xcast packets captured by HA+ are forwarded into X-in-X tunnel interfaces for each FA+ referred to the binding table of HA.. This X-in-X tunneling mechanism can effectively solve the traffic concentration problem of IETF Mobile IP multicast services. Finally WLAN-based testbed is built and a multi-user Instant messenger system is developed as a Xcast application for finally verify the feasibility of the implemented XMIP/Xcast protocols.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.99-103
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• 2009

Recently, as wired and wireless communication services have rapidly developed and multimodal mobile devices which have various characteristics have widely spread, the need for new convergence services increases. The growing population of VoIP technologies and the high communication expense yield that the market of IP based telephony such as WiFi phone and IP phone is substituted for one of the conventional PSTN telephony. With the help of this trend, the wireline network operators desire to find a market in mobile networks. Therefore, they focus on Fixed Mobile Convergence (FMC) service as one of the key factors to accomplish this goal. FMC services are able to provide the mobility of voice services between circuit switched and packet switched networks. IP Multimedia Subsystem (IMS) based Voice Call Continuity (VCC) is one of the schemes to embody FMC services. As Application Server (AS) which has this VCC function provides seamless handover of services between heterogeneous networks, FMC subscribers can communicate seamlessly with others m WiFi domain and COMA domain using WiFi-COMA dual phone. Most of enterprises have already introduced IP network infrastructure and IP-PBX (Private Branch eXchange) for telephony. However, the problems of high communication cost and work inefficiency due to frequent outside jobs or business trips have remained. In order to solve these problems, demands for enterprise FMC services increase. In this paper, we introduce a new IP-PBX based VCC model that can provide seamless handover of voice services between WiFi and COMA networks for enterprise users and we investigate some interworking and security issues between Soft Switch (SSW) and IMS, or between IMSs. In addition, we introduce a new service that can provide the continuity of voice sessions as well as video sessions using Multimedia Session Continuity (MMSC) technology which has evolved from VCC. This service is expected to be one of the next-generation personalized services based on user's context.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.273-278
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• 2007

In the next generation wireless mobile network, various methods are studied to offer interworking and mobility between various radio networks. To offer these harmoniously, network adaptation methods based on IP is generalized, and specifications of host-based mobility method with Mobile IPv4 and Mobile IPv6 to offer IP's mobility are defined in IETF specially. However, it is insufficient to satisfy quality of service that should be offered in wireless mobile network environment. Alternatively studies about Network-Based Mobility of Proxy Mobile IPv4, Proxy Mobile IPv6 etc. are preceded. This paper presents optimum plan that can offer mobility in the next generation radio transfer communication network by comparing and analyzing IP mobility methods divided by Host-based Mobility and Network-based Mobility.

• Journal of KIISE:Information Networking
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• v.33 no.5
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• pp.343-354
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• 2006

There has been much research efforts trying to integrate mobile IP that has been proposed to guarantee the mobility of mobile nodes on MANET (Mobile Ad Hoc Networks) and wired integrated networks. To support the mobility service of nodes in MIPMANET, this paper proposes MAAM(Mobility Agent Advertisement Mechanism) and AMAAM protocols. In MAAM, the mobility agent of the mobile IP can maintain the information of ad hoc networks by broadcasting advertisement messages periodically. AMAAM(Aggregation based Mobility Agent Advertisement Mechanism) is an enhancement of MAAM for reducing the number of transmission of advertisement messages by aggregating them. The proposed schemes are applied in MIPMANET for agent advertisement mechanism. For the performance evaluation of both protocols, we simulated them by NS2. We evaluate the protocols by ns2 with such performance metrics as packet delivery ratio, transmission throughput, and energy consumption.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.402-405
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• 2006

Mobile IP has been designed to have mobile host users move from place to plate without changing their IP address. Ad-hoc network is a provisional network whose mobile host users construct networks by themselves without any assistance of infra structure network, using wireless interface. In this paper we discuss the scheme with which Ad-hoc network users ran access the Internet freely, using mobile IP protocol, and Ad-hot networks are access networks in the spotlight. In this paper we propose algorithm that support enhanced mobility between two Ad-hoc networks applying mobile IP at Ad-hoc routing protocol.

• Electronics and Telecommunications Trends
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• v.35 no.6
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• pp.68-77
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• 2020

Along the advancement of mobile networks, fixed telephone networks are gradually advancing from legacy networks based on copper and circuit-switches to optical cables and packet-switched IP networks. Incumbent fixed-line telephone operators are facilitating the introduction of IP networks and are gradually converting to IP-based facilities according to the investment plans for each operator. As the PSTN's IP conversion exceeds a certain level and VoIP; (an alternative service); is activated, some countries; such as Europe; are considering terminating the PSTN service, centering on operators. In this paper, trends in the procedure, timing, and major issues related to the termination of an overseas PSTN are examined. The domestic status is also examined.

• Journal of Communications and Networks
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• v.7 no.2
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• pp.178-191
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• 2005

Fourth-generation (4G) wireless networks will be the IP-based cellular networks integrating Internet with the existing cellular networks. Two important issues should be concerned in the IP-based cellular networks, IP mobility, and quality-of-service (QoS) guarantees. In this paper, we proposed two mechanisms to solve the problems with IP mobility and RSVP-based QoS provisioning. First, virtual-IP (VIP) allocation scheme in areas with a large rate of handoff can minimize the wireless signaling overhead due to IP mobility. The access routers (ARs) create dynamically the VIP zone by using the measured handoff rate derived from the history of the handoff into neighboring ARs. We show that VIP allocation scheme reduces the binding update messages in the wireless link than hierarchical mobile IPv6. Second, the new advance resource reservation protocol called proportional aggregate RSVP (PA-RSVP) can minimize waste of bandwidth and soft state refresh overhead due to IP mobility. It allocates the bandwidth in advance between the mobility anchor point and neighboring ARs using proportional aggregate reservation. We also show that PA-RSVP provides an improved performance over existing protocols.

• Journal of Communications and Networks
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• v.13 no.4
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• pp.385-392
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• 2011

A loop can take place in the process of managing tree topology for mobility management of mobile nodes in infrastructure-based mobile ad hoc networks. The formation of a loop degrades an effective bandwidth of the wireless network by passing an identical message repeatedly within the same loop. Therefore, the loop should be resolved to revert the system back to the normal state. In this paper, we propose a simple and novel mechanism that detects and resolves a loop quickly by tracking the depth of trees. The mobility management approach that employs the loop resolution method is evaluated comparatively with the original tree-based one and the hybrid one. It is shown that the proposed approach far outperforms the other approaches, and it is robust against the rapid changes in network topology.