• The KIPS Transactions:PartC
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• v.13C no.4 s.107
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• pp.461-470
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• 2006

Recently mobile Stream Control Transmission Protocol (mSCTP) has been proposed as a transport layer approach for supporting mobility. When a mobile terminal (MT) is not located in the home network. a terminal that wishes to communicate with the MT is not able to establish mSCTP association to the MT, since mSCTP does not include the location management mechanism. In order to solve this problem. an interworking approach using the Session Initiation Protocol (SIP) INVITE method has been proposed. However, this approach has shown subsequent delay in acquiring the current location information of the MT when initiating mSCTP association establishment. In this paper, we propose new SIP methods and an approach that minimizes the address acquisition delay (AAD) by utilizing those SIP methods. Mathematical analysis and simulation results show that the proposed approach is more efficient than the previous approach in terms of AAD in all kinds of SIP environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.2
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• pp.296-304
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• 2010

MoIP is technology to transmit a variety of multimedia over IP, but compared to traditional voice services require greater bandwidth and radio resources in a wireless environment has already reached the limits. Therefore, as a way to resolve this issue for header compression is a lot of research. SCTP protocol header compression using ROHC-SCTP has been research, ROHC-SCTP packet structure of the ROHC algorithm with different types and, SCTP header compression to apply the characteristics of the poor performance of many of these have drawbacks. Therefore, in this paper to solve these problems better header compression algorithm was designed. In this paper, the proposed algorithm to evaluate the NS-2 simulation environment was modeled on the header compression operation. Evaluation results, the algorithm designed in this paper compared to ROHC-SCTP algorithms determine the overhead rate was low, the data types vary a lot better when the total header size was small.

• Journal of KIISE:Information Networking
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• v.35 no.3
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• pp.183-191
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• 2008

In this paper, we propose Stream Control Transmission Protocol(SCTP) proxy which supports making an SCTP connection from a Corresponding Node(CN) to a Mobile Node(MN). Recently, mobility support in transport layer is proposed, which provides mobility in end-to-end way using the extension of SCTP. Mobile SCTP can provide handover to all applications that use SCTP as a transport protocol. However, current SCTP does not include independent location management service and can not make connection from a CN to a MN without assistance of other mobile protocols. To solve this problem, Proposed SCTP proxy interoperates with generic location management service and performs an address transformation to forward connection set up messages to the MN. Using the proposed proxy, SCTP can provide a complete mobility support including a connection setup to the MN and maintaining an existing connection.

• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.595-607
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• 2004

Networks often evolve to provide a host with multiple access points to the Internet. In this paper, we propose a transport layer load distribution mechanism utilizing the multiple network interfaces simultaneously. We specifically propose an extension of Stream Control Transmission Protoco1 (SCTP) to have load sharing over multiple network interfaces. We named the particular service provided by the Proposed load sharing mechanism to be LS (Load Sharing) mode service. LS mode service is based on the following four key elements: (i) the separation of flow control and congestion control, (ii) congestion window based striping, (iii) redundant packet retransmission for fast packet loss recovery, (iv) a novel mechanism to keep track of the receiver window size with the SACKS even if they arrive out-of-order. Through simulations, it is shown that the proposed LS mode service can aggregate the bandwidth of multiple paths almost ideally despite of the disparity in their bandwidth. When a path with a delay of 100% greater is utilized as the second path, the throughput is enhanced about 20%.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10b
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• pp.1327-1330
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• 2001

IP 네트워크가 급속도로 성장하고 있고, ISDN, 이동 네트워크, ATM 네트워크 등 다른 통신 구조와 공존하고 있다. 이러한 통신 구조들은 각각 자신의 응용 서비스를 제공하고 있기 때문에 상호 연동 요구가 점차 증가하고 있다. 특히, IP 네트워크를 경유하여 하나의 네트워크로부터 다른 네트워크로 신호 메시지를 전송하고자 하는 요구가 증대되어 왔다. 이에 따라 IETF는 IP 네트워크 상에서 통신 신호메시지 전송을 위한 새로운 프로토콜 SCTP를 개발하고 있다. 본 논문은 SCTP의 개념과 기능적 모듈 그리고 응용을 간단히 고찰하고, IP 네트워크 상에 SCTP를 설계하는 방안을 기술한다.

• Journal of KIISE:Information Networking
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• v.31 no.4
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• pp.393-404
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• 2004

Recently, mSCTP (Mobile SCTP) has been proposed as a transport layer approach for supporting mobility. mSCTP is based on the ‘multi-homing’ feature of Stream Control Transmission Protocol(SCTP), and utilize the functions to dynamically add or delete IP addresses of end points to or from the existing connectionin order to support mobility. In this paper, we propose a mechanism to determine when to add or delete an W address, utilizing the link layer radio signal strength information in order to enhance the performance of mSCTP We also propose a mechanism for a mobile node to initiate the change of data delivery path based on link layer radio signal strength information. In addition, if it takes long time to acquire new data path, we propose an approach for reducing handover latency. The simulation results show that the performance of proposed transport layer mobility support mechanism is competitive compared to the traditional network layer mobility supporting approach. Especially, when the moving speed of mobile node is fast, it shows better performance than the traditional network layer approaches.

• 대한공업교육학회지
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• v.33 no.2
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• pp.287-299
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• 2008

HTTP is one of the most widely used protocols of the WWW. Currently it uses TCP as the transport layer protocol to provide reliability. The HTTP uses separate TCP connection for each file request and adds unnecessary head-of-line blocking overhead for the file retrieval. The web application is short sized and affected by the increased handover latency of TCP in wireless environment. SCTP has attractive features such as multi-streaming and multi-homing. SCTP's multi-streaming and multi-homing avoid head-of-line blocking problem of TCP and reduce handover latency of TCP in wired and wireless environment. Mean response time is the important measure in most web application. In this paper, we present the comparison of mean response time between HTTP over SCTP with that of HTTP over TCP in wired and wireless environments using NS-2 simulator. We measured mean response time for varying packet loss rate, bandwidth, RTT, and the number of web objects in wired environment and mean response time and packet loss rate for varying moving speed and region size in wireless environment. Our experimental result shows that SCTP reduces the mean response time of TCP based web traffic.

• The KIPS Transactions:PartC
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• v.14C no.2
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• pp.163-170
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• 2007

The next generation communication environment consists of various wireless access networks with distinct features that are configured as an overlay topology. In the network environments, the frequency of hand overs should be minimized and the error propagation should be solved in order to provide high-quality multimedia services to mobile users. Therefore, we propose an performance enhancement approach, based on mSCTP, that provides high quality multimedia services to mobile users by ameliorating the error propagation problem. We utilizes the following four functions: 1) the separation of transmission paths according to the types of frames. 2) retransmission strategy to minimize the loss rate of frames, 3) Foced vertical handover execution by utilizing bicasting, 4) using the stability period in order to reduce the effect of the ping pong phenomenon. The simulation results show that the proposed approach provides seamless multimedia service to mobile users by achieving error resilience.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.950-953
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• 2007

무선 인프라와 이동성 지원 기술의 발달로 한 장소에서 머물던 무선 인터넷 서비스를 이동 중에도 받을 수 있게 되었다. 이러한 환경의 변화로 인해 모바일 기기의 이동성에 대한 관심은 더욱 더 커지고 있으며, 이동성뿐만 아니라 유선과 마찬가지로 끊김 없는 서비스를 받고자 하는 요구도 높아지고 있다. 모바일 노드의 이동성을 지원하기 위해서 기존 네트워크 계층의 Mobile IP 와는 달리 전송 계층에서 동작하는 mSCTP (mobile Stream Control Transmission Protocol)가 등장하였다. mSCTP 는 기존 SCTP 의 멀티호밍과 동적으로 IP 주소를 변경할 수 있는 DAR (Dynamic Address Resolution) 시그널을 이용하여 모바일 노드의 핸드오프를 지원하고 있다. 하지만, IP 주소의 추가, 변경 및 삭제에 대한 각 시그널의 전송 시기에 대한 정의가 없어 전송 시기를 결정하는 메커니즘이 필요하다. 따라서 본 논문에서는 퍼지 IF-THEN 룰을 적용한 퍼지 모델을 이용하여 이러한 문제점을 해결하고자 한다. 모바일 노드가 이동하게 될 새로운 네트워크의 신호 세기와 현재 네트워크 신호와의 신호비를 퍼지 모델에 입력하고 그 결과 값을 통해 시그널 전송 시기를 판단한다. 모바일 노드는 핸드오프 시기를 적절히 판단 할 수 있기 때문에 잘못된 핸드오프로 인한 세션의 단절을 줄일 수 있고, 기존에 발생하던 핸드오프 지연 시간을 줄일 수 있어 이동 중에도 손실 없는 서비스를 제공 받을 수 있게 된다.

• Journal of Internet of Things and Convergence
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• v.2 no.1
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• pp.1-6
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• 2016

The IOT environment, people connected to the network, object, everything such as space (Things) generates data in real time. The information between the object collecting, sharing, are utilized. Currently health care, research in various fields such as smart home has been promoted. Also appeared concepts emphasized all things(IOE) Internet connection between the geographic space and the Internet. Human, while important connections between the objects, such as objects, studies of efficient and secure authentication technologies have been developed. In this paper, we propose a RADIUS (Remote Authentication Dial In User Service) protocol for improved mutual authentication between each object in the IOT environment.