• Information and Communications Magazine
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• v.22 no.12
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• pp.105-119
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• 2005

광대역 유선통신망과 무선통신망이 통합되고, 통신과 방송이 융합되는 BcN 환경에서는 서비스 품질(QoS)이 보장되는 다양한 종류의 멀티미디어 서비스가 제공될 수 있어야하며, 다수의 통신방사업자가 제공하는 BcN들 간에 QoS 보장형 차별화서비스 제공을 위한 inter-domain 트래픽 엔지니어링 기능이 제공되어야한다. 특히, BcN 구축 초기 단계에서는 각 통신망 사업자가 개별적으로 구축 및 운영하는 BcN의 NNI signaling과 망운용관리 기능에 많은 차이점이 존재할 것으로 예상되기 때문에, 이들을 효율적으로 연동시킬 수 있는 inter-domain networking 기능 구현방안이 상세히 연구되어야한다. 본 논문에서는 BcN 환경에서의 QoS 보장형 차별화서비스제공을 위한 inter-domain 네트워킹 기술에 대하여 각 영역별로 살펴보며, 상용 BcN간 연동에 적용될 수 있는 트래픽 엔지니어링 및 관련 구현 기술에 대하여 살펴본다. Inter-domain networking 기능 모델로는 유럽연합(EU)의 IP Premium 프로젝트의 일환으로 개발된 MESCAL (Management of End-to-End Quality of Service Across the Internet at Large)을 분석하며, 세부 기능 구현 방안으로 MPLS NNI signaling 기반의 제어정면 연동방안, Web service 구조와 XML 기반의 망운용관리 평면 연동기능 구현 방안에 대하며 살펴본다.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.5
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• pp.3-9
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• 2015

The wireless communication system adopts an appropriate retransmission scheme on each system protocol layer to improve reliability of data transmission. In each system protocol layer, the retransmission scheme operates in independently other layers and operates based on the parameters without reference to end-to-end performance of wireless communication system. For this reason, it is difficult to design the optimal system parameters that satisfy the QoS requirements for each service class. Thus, the performance analysis of wireless communication system is needed to design the optimal system parameters according to the end-to-end QoS requirements for each service class. In this paper, we derive the mathematical model to formulate the end-to-end performance of wireless communication system. We also evaluate the performance at the MAC and transport layers in terms of average spectral efficiency and average transmission delay. Based on the results of performance evaluations, we design the optimal system parameters according to the QoS requirements of service classes. From the results, the HARQ combined with AMC is appropriate for the delay-sensitive service and the ARQ combined with AMC is appropriate for a service that is insensitive to transmission delay. Also, the TCP can be applied for the delay-insensitive service only.

• ETRI Journal
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• v.27 no.2
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• pp.219-222
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• 2005

A promising solution to protect wired Internet networks is to use the Secure Internet Protocol (IPSec); however, this has some drawbacks, particularly on the quality of service (QoS). This paper aims at evaluating the video traffic QoS in terms of end-to-end delay and packet loss rate. Based on some basic assumptions, our analysis shows that the performance with IPSec is rapidly inferior to the IPv4 performance. We thus suggest adding some QoS parameters into IPSec in order to achieve a compromise between QoS and security.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.269-272
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• 2003

Ad hoc 네트워크에 대한 상업적인 관심이 지속적으로 증가함에 따라, 최근 Ad hoc 네트워크에 QoS (Quality of Service)를 지원하기 위한 많은 연구가 이루어지고 있다. 지금까지의 연구는 대부분 QoS 기반 라우팅 프로토콜과 자원 예약 (resource reservation) 그리고 QoS MAC (Medium Access Control) 프로토콜에 관한 것이었다. Ad hoc 네트워크에 QoS를 제공하기 위해서는 위의 요소들이 상호 협력하여 동작하고 Ad hoc 네트워크의 특성이 충분히 고려된 005 모델에 관한 연구가 절실히 필요하다. 본 논문에서는 Ad hoc 네트워크에서 종단 사용자간 (end-to-end) 005를 제공하기 위한 서비스 모델의 설계와 구현방법에 대해 제안하였다.

• Journal of Korean Society for Quality Management
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• v.35 no.3
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• pp.37-46
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• 2007

Our society is increasingly dependent on the Internet, and this trend will be accelerating in the ear of All-IP convergence. As the core infrastructure of the All-IP convergence, the next generation Internet should enable end-to-end Quality of Service(e2e QoS). For that purpose, major international standardization institutes such as ITU(International Telecommunication Union) and IETF(Internet Engineering Task Force) are building the concept and architecture of the Next Generation Network(NGN). However, these institutes focus only on technical issues, and leave many business/policy-oriented challenges unresolved. For example, the standards raised by ITU assume that the entire service delivery process for e2e QoS services is perfectly working. But required is a standardized business interface and process for seamless inter-operations across many stakeholders including ISPs(Internet Service Providers), CPs(Content Providers), so on. On the other hand, TMF(TeleManagement Forum) and QuEST(Quality Excellence for Suppliers of Telecommunication) Forum, global consortiums of telecom operators and vendors, present sets of interface rules and process which playa crucial role as de facto standards: for example, NGOSS/eTOM and TL9000 authorization system. However, these standards focus on telephone services, and provide little principle for the next generation Internet. Our study seeks a way to combine these two strains for a successful implementation of NGN. In particular, we find a missing link in the NGN architecture and the elements that could be complemented with the help of NGOSS/eTOM and TL9000. Finally, presented is a strategic direction that our standardization policy should purse in order to reinforce our global leadership for the next generation Internet.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.11
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• pp.5392-5418
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• 2017

The primary aim of this paper is to propose a non-linear regression based technique for mapping different network Quality of Service (QoS) factors to an integrated end-user Quality of Experience (QoE) or Mean Opinion Score (MOS) value for an online video streaming service on a mobile phone. We use six network QoS factors for finding out the user QoE. The contribution of this paper is threefold. First, we investigate the impact of the network QoS factors on the perceived video quality. Next, we perform an individual mapping of the significant network QoS parameters obtained in stage 1 to the user QoE based upon a non-linear regression method. The optimal QoS to QoE mapping function is chosen based upon a decision variable. In the final stage, we evaluate the integrated QoE of the system by taking the combined effect of all the QoS factors considered. Extensive subjective tests comprising of over 50 people across a wide variety of video contents encoded with H.265/HEVC and VP9 codec have been conducted in order to gather the actual MOS data for the purpose of QoS to QoE mapping. Our proposed hybrid model has been validated against unseen data and reveals good prediction accuracy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12B
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• pp.805-810
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• 2005

According to the user requirements for continuous and real-time multimedia information, the concept of Quality of Service (QoS) has emerged as a main issue in mobile ad-hoc networks. QoS routing is to find the route that meets the QoS requirements of the users. In this paper, we propose a routing protocol that is based on AODV over TDMA, one of the typical routing protocols for mobile ad-hoc networks, by making a bandwidth reservation for QoS guarantee. While the existing schemes calculate the maximum available bandwidth for each candidate path, our scheme is to check only if the bandwidth of a given path satisfies the end-to-end QoS requirement and then to make a reservation by allocating time slots efficiently in the wireless environment. In order to evaluate the performance of the proposed QoS routing protocol, some simulations are carried out in the ad-hoc environment.

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

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.9
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• pp.227-234
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• 2018

Guaranteeing the end-to-end delay deadline is an important issue for quality of service (QoS) of delay sensitive systems, such as real-time system, networked control system (NCS), and cyber-physical system (CPS). Most routing algorithms typically use the mean end-to-end delay as a performance metric and select a routing path that minimizes it to improve average performance. However, minimum mean delay is an insufficient routing metric to reflect the characteristics of the unpredictable wireless channel condition because it only represents average value. In this paper, we proposes a deadline-aware routing algorithm that maximizes the probability of packet arrival within a pre-specified deadline for CPS by considering the delay distribution rather than the mean delay. The proposed routing algorithm constructs the end-to-end delay distribution in a given network topology under the assumption of the single hop delay follows an exponential distribution. The simulation results show that the proposed routing algorithm can enhance QoS and improve networked control performance in CPS by providing a routing path which maximizes the probability of meeting the deadline.

• Journal of Korea Multimedia Society
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• v.17 no.12
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• pp.1453-1460
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• 2014

WFQ (Weighted Fair Queuing) provides not only fairness among traffic flows in using bandwidth but also guarantees the Quality of Service (QoS) that individual flow requires, which is why it has been applied to the resource reservation protocol (RSVP)-capable router. The RSVP allocates an enough resource to satisfy both the rate and end-to-end delay requirements of the flow in the condition of no packet loss, and the WFQ scheduler guarantees those QoS requirements with the allocated resource. In practice, however, most QoS-guaranteed services allow a degree of packet loss, especially from 0.1% to 3% for Voice over IP. This paper discovers that the packet loss rate of each traffic flow is determined by only its time-stamp adjustment value, and then enhances the WFQ to provide a differentiated packet loss guarantee under general traffic conditions in terms of both traffic characteristics and QoS requirements. The performance evaluation showed that the proposed WFQ could increase the utilization of bandwidth by 8~11%.