ICT 융합서비스 환경에서의 종단간 인터넷 서비스 품질 평가에 관한 연구

The International Telecommunication Union (ITU-T) is developing an architecture for Next Generation Network (NGN) to provide end-to-end Quality of Service (e2e QoS), for which Internet service provider (ISP) interconnections play a key role. Furthermore, for an effective e2e QoS-guaranteed interconnection across multiple ISPs, it is of a great help to develop a framework which enables ISPs to trade their unused network capacity. This study presents Hub-and-Spoke (H&S) interconnection model, where the hub called Neutral Internet Business eXchange (NIBX) arranges Bandwidth Trading (BT) on the basis of the market mechanism. After introducing qualitative and quantitative justifications of the H&S NIBX interconnection model, we propose a platform prototype for BT based upon the H&S NIBX architecture. Presented also are some detailed descriptions of key functional elements together with decision models embedded in the functions. Operations scenarios show potential benefits of the NIBX + BT architecture for ensuring e2e QoS, the ultimate goal of ITU-T’s NGN.

In the internet telephony market with fierce competition, enhancing the service quality and the customer satisfaction to increase the customer's positive behavior intention has become a significant issue for all internet telephony operators. The goal of our study is to analyze the relationships among service quality, service value, customer satisfaction and behavior intention for internet telephony services. Based on the paper-based and web-based questionnaires, the study has accepted 260 effective responses from people who have tried to use the internet telephony services before. The questionnaires collected are processed by LISREL for further analysis. The study results reveal that: 1. The ”reliability/quality” has the most influence on the service value. The other influence factors in order are ”ease of use” and ”privacy/security”. 2. The ”reliability/quality” has a positive influence on the customer satisfaction. 3. (1) The ”reliability/quality” has a positive influence on the ”loyalty”. (2) The ”privacy/security” has the most influence on the ”pay more”. The other influence factors in order are the ”reliability/quality” and ”ease of use”. 4. The service value has a positive influence on the ”customer satisfaction”. 5. The service value has a positive influence on the ”loyalty”. 6. The customer satisfaction has a positive influence on the ”pay more”. Aggregately, the most significant relationship is that the better service quality an internet telephony operator can provide, the more positive behavior intention the customers will tend to show. Next, the more service value an internet telephony operator can have, the more positive behavior intention the customers will tend to show. The least influence factor to behavior intention is customer satisfaction. Accordingly, a good product design with high reliability/quality, ease of use and service value can increase the user's loyalty and willingness to pay more.

Content delivery networks (CDNs) deliver Web content to end-users from a large distributed platform of Web servers hosted in data centers belonging to thousands of Internet service providers (ISPs) around the world. The bandwidth cost incurred by a CDN is the sum of the amounts it pays each ISP for routing traffic from its servers located in that ISP out to end-users. A large enterprise may also contract with multiple ISPs to provide redundant Internet access for its origin infrastructure using technologies such as multihoming and mirroring, thereby incurring a significant bandwidth cost across multiple ISPs. This paper initiates the formal study of bandwidth cost minimization in the context of a large enterprise or a CDN, a problem area that is both algorithmically rich and practically very important. First, we model different types of contracts that are used in practice by ISPs to charge for bandwidth usage, including average, maximum, and 95th-percentile contracts. Then, we devise an optimal offline algorithm that routes traffic to achieve the minimum bandwidth cost, when the network contracts charge either on a maximum or on an average basis. Next, we devise a deterministic (resp., randomized) online algorithm that achieves cost that is within a factor of 2 (resp., e/(e - 1)) of the optimal offline cost for maximum and average contracts. In addition, we prove that our online algorithms achieve the best possible competitive ratios in both the deterministic and the randomized cases. An interesting theoretical contribution of this work is that we show intriguing connections between the online bandwidth optimization problem and the seemingly-unrelated but well-studied ski rental problem where similar optimal competitive ratios are known to hold. Finally, we consider extensions for contracts with a committed amount of spend (CIRs) and contracts that charge on a 95th-percentile basis

인터넷 전화, 인터넷 방송 VPN(Virtual Private Networks), 멀티미디어 서비스 등의 실시간 혹은 대역폭 요구 서비스 등의 실시간 혹은 대역폭 요구 서비스들이 늘어남에 따라 인터넷에서도 서비스 품질(QoS : Quality of Service)에 대한 요구가 중요한 문제가 되었다. 인터넷 응용 서비스의 품질을 보장하기 위하여 통합 서비스, 차등 서비스, 그리고 MIPLS(Multi-Protocol Label Switching) 등의 여러 가지 방안이 강구되고 있다. 본 논문에서는 차등 서비스(DiffServ : Diferentiated Service)를 이용한 QoS 보장 기법의 성능 해석에 대하여 기술하였다. 차등 서비스의 성능이 다양한 입력 트래픽 모델과 WFQ(Weighted Fair Queueing) 가중치에 의하여 어떻게 영향을 받는지 분석하기 위하여, 랜덤, 버스티, 자기유사 입력 트래픽 모델과 다양한 입력 파리미터에 대하여 모의실험과 성능평가를 수행하였다. 성능분석 결과, 사용된 입력 트래픽 모델에 따라 패킷 지연 rqkt과 손실 사이에 상당한 차이가 발생함을 확인할 수 있었다. 그러나, 모든 입력 트래픽 상황에서, EF(Expedited Forwarding)의 성능은 보장이 가능하고, EF와 BE(Best Effort) 클래스의 서비스가 분리가 가능한 것으로 나타났다. 다음으로 성능 합성(Performance Synthesis) 문제에 대하여 기술하였다. 차등 서비스 망에 대한 보존법칙을 유도하고, WFQ 방식에서 자원의 분배(즉, 가중치)에 따른 성능 변화와 동적 행위에 대하여 분석하였다. The requirement for QoS (Quality of Service) has become an important Issue as real-time or high bandwidth services are increasing, such as Internet Telephony, Internet broadcasting, and multimedia service etc. In order to guarantee the QoS of Internet application services, several approaches are being sought including IntServ (Integrated Service) DiffServ(Differentiated Srvices), and MPLS(Multi-Protocol Label Switching). In this paper, we describe the performance analysis of QoS guarantee mechanism using the DiffServ. To analyze how the DiffServ performance was affected by diverse input traffic models and the weight value in WFQ(Weighted Fair Queueing), we simulated and performed performance evaluation under a random, bursty, and self-similar input traffic models and for diverse input parameters. leased on the results of performance analysis, it was confirmed that significant difference exist in packet delay and loss depending on the input traffic models used. However, it was revealed that QoS guarantee is possible to the EF (expedited Forwarding) class and the service separation between RF and BE (Best Effort) classes may also be achieved. Next, we discussed the performance synthesis problem. (i. e. derived the conservation laws for a DiffServ networks, and analysed the performance variation and dynamic behavior based on the resource allocation (i.e., weight value) in WFQ.

This paper analyzed major factors affecting video quality in IPTV (Internet Protocol TV) services in multicasting under our lab network environment similar to practical IPTV service networks. We measured video qualities for the broadcasting traffics in IPTV multicasting with or without applying QoS (Quality of Service) technique. The measurements allowed us to extract thresholds of network measurement factors affecting the quality for the service. It will be a good choice that the factors can be a reference to ensure stable video quality for practical IPTV services in multicasting.

Achieving high robustness and performance in QoS-aware route planning for IPTV networks

IPTV 멀티캐스팅 서비스에서 증가되는 네트워크 트래픽 로드에 따른 화상 품질 측정과 화상 품질 변화에 대한 연구는 IPTV 서비스에 대한 관심이 현실화됨에 따라 필요하게 되었다. 본 연구에서는 네트워크 트래픽 로드에 따른 화상 품질의 효과가 주어지는 네트워크 성능 요소의 최적의 값을 파악하기 위하여, 테스트 베드 네트워크를 통하여 테스트 하는 S/W를 개발하였다. 그리고 테스트 환경을 학교 네트워크로 확장하여 실제 IPTV 서비스 환경과 비슷한 학교 네트워크에서 네트워크 트래픽 로드 증가에 따른 IPTV 멀티캐스팅 서비스의 화상 품질 변화를 측정하고자 하였다. The research of image quality estimation standard and the image quality change according to the network traffic load increase at IPTV multicasting service is necessary because the concern of IPTV(Internet Protocol TV) service become active recently. In the research, for finding out the threshold value of network performance elements giving the effect to the image quality according to the network traffic load, we developed S/W to operate the test bed network and make the test scenario through test bed network test and then we expand the test environment scope to the college network and try to measure the image quality change of IPTV multicasting service according to the network traffic load increase at the college network similar to the real IPTV service environment.

Cost savings and the ease of developing and adding new services have motivated great interest in Internet telephony, which integrates services provided by the Internet with the public switched telephone network (PSTN). Internet telephony relies on several protocols, including the real-time transport protocol (RTP) for multimedia data transport and the session initiation protocol (SIP) or H.323 for establishing and controlling sessions. SIP can integrate with other Internet services, such as email, the Web, voice mail, instant messaging, conference calling, and multimedia collaboration. We have implemented a SIP-based software suite called the Columbia Internet extensible multimedia architecture (Cinema), which we installed and integrated with the existing private branch exchange (PBX) infrastructure in the computer science department at Columbia University. The Cinema environment provides interoperability with the PSTN, programmable Internet telephony services, and IP-based voice mail. It also integrates Web access and e-mail for unified messaging and supports multiparty multimedia conferencing. The setup lets us extend our PBX capacity and will eventually let us replace it while keeping our existing phone numbers. It also provides an environment in which we can easily add new services and features, including interoperation with existing multimedia tools, e-mail access from standard. telephones, network appliance control, and instant messaging support.

Multihoming has been broadly employed by large enterprises, and stub networks to augment the availability and reliability of their Internet access. In this technique, the edge network is connected to the Internet through multiple upstream Internet Service Providers (ISPs) rather than one. Thus far, different aspects of multihomed networks have received intensive attention in the research community. However, there have been quite a few works on the selection methodologies of upstream ISPs for a multihomed network which is definitely a primary prerequisite for other challenges in this area. In this paper, we try to address the ISP selection problem for provisioning of survivable end-to-end connections in multihomed networks. We first argue about different design decisions that the network operator has to make for support of resiliency against single-link network failures. Then, the minimum ISP selection problem is defined in which the goal is to pick the minimum number of upstream ISPs such that by multihoming to them, the major connections of the network would achieve a satisfactory level of resiliency against link failures. Then, we propose a brute-force method to optimally unravel this problem. Despite the NP-hardness of our problem, we show that the proposed method can be used in practice to solve the problem in tolerable manner.

At present time the ISP (Internet Service Provider) already make a great impact to the human life as well as the economic society, everything has a close relation with the internet service and due to the fast development of information technology further lower the cost of ISP and improved the service speed as well as its quality. All of this make the customer layer of ISP more popular than before and thus bring up the fierce competition in this industry. Due to the entry barrier of high investment and high technology of ISP industry it has become as a monopoly market and the monopoly market is very respect the competition and cooperation relationship with competitors. Besides, most of the relevant literature in the past is focus on the measurement and analysis of customer to the self-company and few of them mention how to include the satisfaction of competitor’s customer into measurement and analysis. As golden strategy stated in the Sun-Tze Strategic: “Know yourself and know your competitor well, winning every war.” we must consider the strength, weakness, opportunity and threat on customer satisfaction of your company and competitors. Base on the above motivation, this article will apply the DMAIC (Define, Measure, Analyze, Improve, Control) methodology of 6-Sigma, focus on the viewpoint of customer satisfaction of ISP industry. At first we utilize the 5 equal scale measurement define the network quality item of ISP, which provided by the self-company and competitors. And measuring the degree of “satisfaction” and “importance” of these quality items, then use the performance evaluation matrix and strength and weakness matrix to analyze the Strength, Weakness, Opportunity and Threat of self and competitors, focus on the quality items that fall out of the 2 sigma and use the strength–weakness strategic chart to establish the improvement strategy. And at last, utilize the strength–weakness matrix chart as the control tool to verify and sustain the effectiveness of the improved performance. The complete and easy measurement improvement model provided in this article can be used by the enterprise to effectively and quickly evaluating and analyzing the service quality of self and competitors. And under the reasonable cost condition with considering the competing opportunity and threat of market to effectively improving the customer service quality and promoting the overall customer satisfaction and create powerful high value-added quality competition strength.

An internet service provider (ISP) tries to maximize profit by choosing an appropriate price for an offered service. In this paper, a system of two identical ISPs is considered. When ISPs independently choose a price to charge to maximize profit and each ISP repeatedly tries to improve profit by changing the price till no further improvements are possible, they may reach an equilibrium called the Nash equilibrium. Another strategy is that one ISP announces an appropriate price in advance and the other ISP chooses the best response strategy. This leads to Stackelberg competition. Both these strategies are compared in the paper. In this paper, it is assumed that few clients have access to multiple ISPs by using multi-SIM handheld devices such as smartphones and tablets. The clients who have access to multiple-ISPs choose an appropriate ISP for service based on the price of the service. The clients who have access to only one ISP, have no choice but to take service from the ISP. Simulations show that the ISP who announces an appropriate price in advance is likely to do better as compared to the ISP who decides the price later after observing the price of the announcer. Simulations also show that announcing an appropriate price in advance is better instead of independently deciding the price which may lead to a Nash equilibrium in terms of profit of the ISPs and quality of service provided to the clients.

1k x 1-bit static RAM

This paper analyses wireline broadband Quality of Service (QoS) metrics of India’s small and medium Internet Service Providers (ISPs). Key Performance Indicators (KPIs) used in this analysis are – Fault repair (>90% in 1 working day and >=99% in 3 working days), Response time to customer for voice-to-voice operator assistance (in 60 sec. >60% and in 90 sec. >90%), Broadband connection speed from ISP to node (Download speed) and Service availability/uptime. Benchmarks are arrived at, using the Slack Based Measure (SBM) in Data Envelopment Analysis (DEA). Twenty Decision Making Units (DMUs – ISPs) were used in the analysis with eight of them needing to improve their QoS on some of the mentioned parameters. Relative benchmark providers for all providers needing improvement with their weightage are found and optimal targets by each QOS metric is mathematically arrived at.

Network Slicing (NS) technique is comprehensively reshaping the next-generation communication networks (e.g. 5G, 6G). Software-Defined Networking (SDN) and Network Functions Virtualization (NFV) predominantly control the flow of service functions on NS to incorporate versatile applications as per user demands. In the virtualized-Software Defined Networking vSDN environment, a chain of well-defined virtual network functions (VNFs) are installed on Service Function Chains (SFCs) by multiple Internet Service Providers (ISPs) concurrently. Generation, allocation, re-allocation, release and destroying associative VNFs on SFC is an extremely difficult task while keeping high selection accuracy. Towards solving this fundamental issue, in this work, we have proposed a multi-layered SFC formation for adaptive VNF allocation on dynamic slices. We have formulated an ILP to address the VNF-EAP (VNF-Embedding and Allocation Problem) over real network topology (AT&T Topology). Leveraging machine learning techniques we have shown an intelligent VNF selection mechanism to optimize resource utilization. The performance evaluation shows remarkable efficiency on ML-driven dynamic VNF selections over static allocations on SFCs by halving resource usage. Further, we have also studied a VNF typecasting technique for service backup on outage slices in the field of disaster management activities.

To manage and enable service customization among multiple internet service providers (ISPs) sharing the common physical infrastructure and network capacity in virtualized Wi-Fi networks, this paper models and optimizes access point-station (STA) association via airtime usage control. More specifically, an optimization problem is formulated on the STAs' transmission probabilities to maximize the overall network throughput, while providing airtime usage guarantees for the ISPs. As the proposed optimization problem is inherently non-convex, an algorithm to reach the optimal solution is developed by applying monomial approximation and geometric programming iteratively. Based on the proposed 3-D Markov-chain model of the enhanced distributed channel access protocol, the detailed implementation of the optimal transmission probability of each STA is also discussed by manipulating medium access control parameters. The performance of the developed association and airtime control scheme is evaluated through numerical results. For both homogeneous and non-homogeneous STA distributions, numerical results reveal performance gains of the proposed algorithm in improving the throughput and keeping airtime usage guarantees.