• Journal of the Korea Society of Computer and Information
• /
• v.13 no.1
• /
• pp.175-183
• /
• 2008

QoS-support technology in networks is based on measuring QoS metrics which reflect a magnitude of stability and performance. The one-way delay measurement of the QoS metrics especially requires a guarantee of clock synchronization between end-to-end hosts. However, the hosts in networks have a relative or absolute difference in clock time by reason of clock offsets. flock skews and clock adjustments. In this paper, we present a theorem, methods and simulation results of one-way delay and clock offset estimations between end-to-end hosts. The proposed theorem is a relationship between one-way delay, one-way delay variation and round-trip time And we show that the estimation error is mathematically smaller than a quarter of round-trip time.

• Proceedings of the KIEE Conference
• /
• 2004.05a
• /
• pp.68-70
• /
• 2004

In this paper we develop an adaptive interface between video compression and transission protocols to handle QoS fluctuations that are common to mobile communication systems. We consider various generic design alternatives for QoS adaptation and identify 'QoS negotiation' as the most promissing. This method gives the best possibilities to obtain system-wide efficiency. To handle the indued system complexity we apply a design philosophy (called ARC) that separates implementation dependencies by introducing QoS interfaces between system modules. In the ARC phlosophy the implementation details are hidden in the subsystems. To assure efficient adaptation, the QoS must be negotiated between modules. We select the QoS parameters that are both necessary and sufficient for efficient negotiation between the video encoder and protocol modules. We describe the relation between the QoS parameters at the interface and the internal parameters of common video coding methods and protocol elements. Furthermore, we describe a negotiation procedure that allows a system-wide optimum to emerge.

• Proceedings of the Korean Information Science Society Conference
• /
• 2001.10c
• /
• pp.358-360
• /
• 2001

In Integrated Services Internet the Resource Reservation Protocol (RSVP) provides a signaling mechanism for end to end QoS. In this paper, we propose a novel scheme using a Hierarchical Mobile Agents Tree (HMAT) based on the definition of new option called QoS Object Option (QOO) in order to improve the efficiency during handoff in Integrated Services Internet. Mobile agents are required to manage QOO, resource reservation and other mobility related basks un behalf of mobile hosts. This scheme is based on Mobile IPv6.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.16 no.2
• /
• pp.160-168
• /
• 2013

In tactical environment, tactical wireless networks are generally comprised of Tactical MANETs(T-MANETs) or Tactical WMNs(T-WMNs). The most important services in tactical network are voice and low rate data such as command control and situation awareness. These data should be forwarded via multi-hop in tactical wireless networks. Urgent and mission-critical data should be protected in this environment, so QoS(Quality of Service) must be guaranteed for specific type of traffic for satisfying the requirement of a user. In IEEE 802.11s, TDMA-based MAC protocol, MCCA(MCF Controlled Channel Access), has a function of resource reservation. But 802.11s protocol can not guarantee the end-to-end QoS, because it only supports reservation with neighbors. In this paper, we propose the routing protocol, R-HWMP(Reservation-based HWMP) which has the resource reservation to support the end-to-end QoS. The proposed protocol can reserve the channel slots and find optimal path in T-WMNs. We analyzed the performance of the proposed protocol and showed that end-to-end QoS is guaranteed using NS-2 simulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.1
• /
• pp.573-577
• /
• 2005

Recently there are increasing needs for Internet and various kinds of contents. These traffics for various contents need more amount of data to provide high-quality information and require various QoS depending on the characteristics of contents. However, current Internet service supports BE (Best Effort) service only, therefore IntServ (Integrated Service) scheme and DiffServ (Differentiated Service) scheme are represented to support QoS in IP layer. Moreover, while wireless Internet is getting popular, MAC(Medium Access Control)is also becoming important. This is due to the fact that wireless access, resource allocation and packet scheduling, which are done in another layers before, are performed in MAC layer in many new wireless systems. This paper describes new scheme that provides QoS taking into account the traffic characteristics over Mobile IPv6 network based on IEEE 802.11e EDCF and evaluates the performance through computer simulation.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.2 no.1
• /
• pp.17-23
• /
• 2007

The home network has been revitalized due to the emergence of the high-speed broadband network and explosive increases of the home network services. Especially multicast based high-definition (HD) IPTV service is on high demand from both Internet service provider (ISP) and users. In order to provide high quality HD IPTV service without packet loss and delay, the ISP utilizes various network QoS mechanisms. Due to the misleading fact, that the home gateway is considered as an end terminal in terms of the ISP's viewpoint, the ISPs can not guarantee the end-to-end QoS within the scope of the current home network architecture. Therefore, an independent QoS guaranteed mechanism should be considered within the home network domain. As the home gateway manages both private home and public access network within the home network, we propose and implement a novel QoS mechanism for the multicast based HD IPTV service over the home gateway. In order to provide QoS guaranteed HD IPTV service, the proposed mechanism classifies the packets, manages home network bandwidth resources, and executes call admission control using the channel join message. Also, we utilize layer 2 multicast packet forwarding scheme to improve the overall performance of the home network services. Through the experiments of implementing the multicast based HD IPTV services, we will verify the efficiency of the proposed mechanism.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38C no.3
• /
• pp.327-333
• /
• 2013

In this paper, we propose a QoS information collection method at the information server in maritime networks with multi-network interfaces, and a route selection scheme based of the measured predictive QoS information comparing with parameters requested from a mobile node in a ship entering into a harbor from near-shore area. By changing network conditions and applying various application bandwidths, we check the operation of our proposed scheme and measure its performance of the original and proposed schemes in the viewpoints of the received packet traffic and end-to-end delays.

• 한국IT서비스학회:학술대회논문집
• /
• 2008.05a
• /
• pp.541-545
• /
• 2008

SOA는 하나의 시스템이 아니며 다양한 서비스를 제공하기 위한 다양한 시스템이 SOA개념 하에 서로 유기적으로 연계되어 있다. 이러한 SOA를 실현하는 미들웨어이며, 분산된 서비스 컴포넌트의 효율적인 통합을 실현하는 ESB는 BPEL 혹은 솔루션 벤더의 자체적인 표준을 따르는 프로세스 매니저와 연동해 프로세스 기반의 통합을 지원한다. 기업 차원에서 볼 때, 안정적인 SOA를 기반으로 BPM을 구축하면 BPM이 보다 민첩하고 유연해지며, 여러 부서와 위치에 걸쳐 BPM을 보다 쉽게 확장할 수 있고, 기본 IT 시스템의 변화에 보다 탄력적으로 대응할 수 있다. 또한, 프로세스에 필요한 일부 서비스를 거래 파트너에 아웃소싱할 수 있고, 회사의 고유한 프로세스를 내외부의 신규 고객에게 서비스로 제공할 수 있는 새로운 비즈니스 모델을 만들 수 있다. 이런 비즈니스 프로세스를 운영하면서 서비스에 대한 품질과 각 프로세스에 대한 관리를 효율적으로 하기 위하여 본 논문에서는 EERP (End to End Resource Planning)을 적용하여 QoS를 보장하고자 한다. EERP는 SO(Service Oriented)-SCM이나 SO-CRM과 같은 엔터프라이즈 환경에서의 내부, 외부의 리소스들을 최적화 하며, 프로세싱에 사용되는 각 리소스들을 실시간으로 감시하며 QoS를 보장하는 매커니즘을 통하여 최적화한다. 이를 기반으로 본 논문에서는 이러한 EERP QoS 구조를 제시한다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.04a
• /
• pp.775-777
• /
• 2004

본 논문은 다수의 DiffServ(Differentiated Service) 도메인을 지나가는 Assured Forwarding(AF) 서비스 클래스의 종단간 QoS(Quality of Service)툴 향상시키는 새로운 Marking Mechanism을 제안한다. 기본적인 개념은 패킷들이 최초 DiffServ 도메인으로 들어갈 때 부여받은 Marking 정보를 종단까지 유지하고, 이 정보를 근간으로 Marking을 수행하여 종단간 QoS를 보장받도록 해주는 것이다.

• Proceedings of the KAIS Fall Conference
• /
• 2011.05a
• /
• pp.428-432
• /
• 2011

차량 통신 네트워크(VANET, Vehicle Ad hoc NETwork)는 ITS(Intelligent Transport System)의 발전과 함께 운전자의 안전 및 교통 정보, 긴급 메시지 등과 같은 서비스를 실시간으로 가능하게 할 수 있는 차세대 네트워크 기술이다. 이러한 차량 통신 네트워크는 현재 IEEE P1609에서 정의하고 있으며, WAVE(Wireless Access Vehicular Environment)로 알려져 있다. WAVE는 차량에 설치된 OBU(Onboard Unit)와 주변시설에 설치된 RSU(Road Side Unit)을 통하여 통신하며, 차량 간 통신을 지원하는 V2V(Vehicle to Vehicle)와 차량과 주변시설과의 통신을 지원하는 V2I(Vehicle to Infrastructure)로 나뉘어져 있다. 하지만 WAVE에서 정의하고 있는 네트워크 서비스(IEEE P1609.4)는 OBU와 RSU 간의 네트워크 서비스에 초점을 맞추고 있기 때문에 전체 네트워크의 QoS를 보장하기에는 미흡한 상태이다. 따라서 본 논문에서는 차량 통신 네트워크에서 End-to-End 간의 QoS 보장을 위한 무선 메쉬 네트워크 기반의 라우팅 알고리즘을 제안한다. 제안하는 알고리즘은 무선 메쉬 네트워크 노드의 호스트 라우터 기능을 통하여 차량 노드와 이기종 간의 네트워크 서비스를 가능하게 하며, 무선 메쉬 네트워크의 다중 채널을 이용하여 데이터의 중요도에 따른 차등 서비스를 지원한다. ns-2를 이용한 시뮬레이션 결과 제안하는 알고리즘이 QoS를 보장함으로써 차량 통신 네트워크의 성능을 향상시킬 수 있음을 입증하였다.