• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3B
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• pp.144-152
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• 2005

Mobile IP(MIP) and SIP have been proposed to support mobility in the wireless internet working at different layers of the protocol stack. However MIP has some problems such as triangle routing, the need of each host's home address, the overhead of tunneling and the lack of wide deployment. Thus we proposed a scheme for supporting mobility based on SIP in this research. A novel SIP system to provide a hierarchical registration has been designed according to this scheme. Our SIP system has been established by implementing JAIN technologies which follow next generation network standards to support the mobility of wireless terminal. This system successfully satisfied ITU-T recommendation.

• Journal of Internet Computing and Services
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• v.13 no.3
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• pp.1-16
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• 2012

Cost-effective mobility management for the roaming mobile users is very important in the seamless services on next-generation wireless network (NGWN). MIPv6 (Mobile IPv6) is one of the mobility management schemes proposed by the IETF (The Internet Engineering Task Force) and various IPv6-based mobility management schemes have been developed. They are directly involved with data transfer from MN (Mobile Node). In this paper, two kinds of schemes in analyzing of mobility management schemes are proposed. The signaling transfer and packet delivery procedures for each mobility management schemes are analyzed, respectively. The signaling cost for mobility management schemes are calculated, and the cost of each protocol are analyzed numerically. In other word, applying the sum of signaling cost and packet delivery cost to each mobility management scheme, their costs are analyzed. Finally, our performance evaluation results that the network-based mobility management scheme shows better performance in terms of overall cost.

• Journal of Korea Multimedia Society
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• v.10 no.1
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• pp.74-82
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• 2007

IPv6 is the internet protocol for next generation which can solve the problem of IPv4 protocol. Mobile IPv6 efficiently provides the mobility for mobile devices holding the properties of IPv6. iSCSI(Internet Small Computer System Interface) is a block-oriented storage access protocol that enables a user to recognize a remote storage as their own local block device through general TCP/IP networks. Since iSCSI uses a standard Ethernet switch and router for this kind of access, it can not only be applized to Ethernet technologies, but can also be used to create a storage networking system without any distance restrictions that can equally be applied to a wireless network environment. Accordingly, this paper presents an alternative approach to overcome the limited storage space of mobile devices based on the IPv6 iSCSI initiator driver which was originally designed for wired networks. Also, this paper describes about the implementation and performance analysis of mobile education service system using virtual storage devices in IPv6 wireless networks.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.643-645
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• 2002

현재 웹기반의 네트워크 침입 탐지 시스템은 관리자가 네트워크가 연결된 상태어서 관리자가 컴퓨터 앞에서 감시하고 그에 적절한 대응을 해야 하지만 관리자가 자리를 비웠을 경우에는 그러한 침입에 신속하게 대응하기가 어렵다. 하지만 무선 인터넷의 발달로 인하여 관리자가 무선 단말기 상에서 네트워크 침입탐지를 감지하고 그에 적절한 대응을 할 수 있게끔 하기 위해서 본 논문을 작성하게 되었다. 본 논문에서는 WAP Push Framework 기술을 바탕으로 해서 모바일 기반에서 시스템 관리자가 장애탐지, 네트워크 모니터링, IP관리 등을 직접 무선 단말기 상에서 관리함으로써 IDS관리를 좀더 효율적으로 관리할 수 있을 것이다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.1
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• pp.16-22
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• 2017

In this paper, we first introduce a mobile data traffic offload method called Local IP Access (LIPA) with femtocell networks. Then, we evaluate the traffic transmission time and probability of mobile data traffic that is transmitted to the core network (CN) when mobile devices transmit the mobile data traffic to indoor devices in three different scenarios, i.e., conventional systems, femtocell based systems, and femtocell and LIPA based systems. Through performance results, it is shown that the next generation mobile network with the femtocell and LIPA not only decrease the density of the mobile data traffic in CNs but also reduce the total transmission time of the mobile data traffic in indoor environments. That is, for the traffic transmission time, the conventional systems and femtocell based systems have 3 and 4 times higher than the femtocell and LIPA based systems, respectively, when the Internet delay is 10ms while 14 and 26 times higher than that, respectively, when the Internet delay is 100ms.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.8 s.350
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• pp.15-24
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• 2006

We design and implement explicit mobile multicast, named XMIP, by enhancing explicit multicast for a great number of small group multicast communications. XMIP is a straightforward multicast mechanism without maintaining multicast states due to the inheritance from the explicit multicast based on a unicast routing. This research modifies and extends the functionality of each mobility agent of IETF Mobile IP for interworking XMIP XMIP Packets captured by an extended home agent are forwarded to each extended foreign agent through nested tunnels, named X-in-X tunnels, made by the binding table of the extended home agent. X-in-X tunneling mechanism can effectively solve the serious traffic concentration problems of Mobile IP multicast specifications. Finally heterogeneous mobile networks as an XMIP testbed including CDMA2000 1X EV-DO and WLAN are actually established, and a multi-user instant messenger system for small group communications is developed for verifying the feasibility of the proposed protocols.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.5
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• pp.528-533
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• 2010

Currently the telephone service using Internet grows and the recent introduction of a smart phone is expected to accelerate the trend. In particular, considering the domestic situation that the wireless broadband (WiBro) system deployed over the nation, the telephone service over WiBro can be a solution toward its fast expansion. Unlike telephone service over a conventional telephone network or mobile network, however, internet telephone cannot guarantee it service quality, which can be severer in a wireless environment such as a WiBro network. Therefore, a more strict and systematic management for controlling the quality of internet telephone service over WiBro in a more efficient way. As the first step to establish the management system, this paper proposes a scheme to manage the quality of internet telephone service over WiBro and introduces a software developed for the purpose. The developed software is installed on a user terminal and facilitates efficient service quality management by measuring the quality of internet telephone service over WiBro in terms of VoIP metric, network metric, and wireless metric.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10a
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• pp.381-384
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• 2006

휴대폰, PMP, PDA와 같은 모바일 기기의 사용은 일상이 되었고 최근 이러한 기기들 간의 컨버전스화가 활발히 진행 중이다. 일반적으로 모바일 기기는 제한적인 배터리를 장착하고 있기 때문에 저전력성은 매우 중요한 기능 중의 하나로 간주되고 있다. 본 논문에서는 모바일 기기에 사용할 수 있는 다양한 스토리지 환경에서 대해서 논하고, 동영상 재생 시에 각 장치에서 소모전력을 측정하고 그 패턴을 분석한다. NAND 플래시를 이용할 경우에 Idle 상태에 비해서 33%이상의 추가 전력소모가 발생하였으며, HDD, WLAN을 이용한 NFS기반의 네트워크 스토리지, 그리고 본 연구를 통해 처음 구현된 모바일 기기용 객체기반 IP 스토리지의 경우 NAND 플래시에 비해서 약 3배 이상의 높은 전력이 소모됨을 볼 수 있었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4878-4883
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• 2015

The IP Multimedia Subsystem(IMS) is a framework that provides access to the content of Internet and Telecom services anytime and anywhere with guaranteed Quality of Service(QoS) and manageability by separating control functions from bearer and services. The Service Delivery Platform(SDP) provides common interfaces and protocols to deploy existing or new services in an efficient way. Therefore SDP over IMS plays a role of bridge between established network and new IMS network by simplifying the interaction among application services. In order to enrich the multimedia network communication, we try to deploy the Push-to-talk over Cellular(PoC) service which is considered as the outstanding and distinguished half-duplex Voice over IP(VoIP) application service among deployable candidate services over mobile network. In this paper we investigate the advantages of PoC service and PoC architecture firstly, and then focus on the its practical implementation for the prototype to validate the feasibility of its deployment and realization.

• Information and Communications Magazine
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• v.32 no.4
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• pp.16-22
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• 2015

유비쿼터스 정보 기술을 기반으로 다양한 업무 지원 기기간 네트워크를 형성하여 업무 처리를 지원하는 u-Office와, 지능화된 다양한 사물에 인터넷 연결성을 제공하여 지능적 서비스를 제공하는 Internet of Things(IoT)는 기하급수적으로 증가하는 다수의 객체간 통신을 수행하므로 네트워킹 자원의 최적화 기술이 필수로 뒷받침되어야 한다. 데이터 패킷의 오버헤드를 줄이고 통신 자원을 절약하기 위한 기술 연구는 다방면으로 진행되고 있으며, 특히 패킷의 오버헤드를 줄이고 통신 자원을 절약하는 패킷 헤더 압축 기술은 다양한 국제 표준이 개발되어 모바일 와이맥스(Mobile WiMAX), Long Term Evolution(LTE), IPv6 over Low power Wireless Personal Area Network(6LoWPAN) 등의 네트워크에 활용되고 있다. 본 고에서는 모바일 와이맥스, LTE, 6LoWPAN에서 각각 사용되는 패킷 헤더 압축 기술인 Payload Header Suppression(PHS), Robust Header Compression(ROHC), Header Compression(HC), Improved Header Compression(IPHC)의 개발 동향을 제시하고 각 기술의 특징을 비교 분석한다.