• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.610-613
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• 2002

To improve quality of service(QoS) in the current Internet, various QoS providing mechanisms such as RSVP, DiffServ have been proposed. In this paper we propose a more simple but more scalable mechanism which can guarantee end-to-end QoS. The proposed mechanism can provide scalability by minimizing the state information which is needed by router to reserve network resources. Using sender-initiated & soft-state resource reservation, a router does not need to keep the backward data path like RSVP. In this paper we illustrate the proposed resource reservation mechanism with network topology and signaling.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4C
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• pp.342-352
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• 2002

In this paper, we compare the performances of RIO and RIO-DC buffer management schemes for DiffServ AF PHB standardized in IETF. For the comparison, we relatively differentiate maximum delay for each Assured Service subclass in Differentiated Services by allocating bandwidth to each subclass differently. In addition, we set the values of RIO and RIO-DC parameters considering the buffer size determined by the network topology and the ratio of bandwidth allocated to each subclass. In this simulation environment, the performances of RIO and RIO-DC schemes are analyzed focusing on the throughput of the In-profile traffic, the link utilization and the fairness. Simulation results show that the performance of RIO-DC scheme is comparable to that of RIO scheme with regard to the throughput of the In-profile traffic and the link utilization. However, under the simulation condition RIO-DC scheme improves the fairness between flows much better than RIO scheme.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.4
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• pp.497-507
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• 2018

Tactical networks are evolving into an All-IP based network for network centric warfare(NCW). Owing to the flexibility of IP based network, various military data applications including real-time and multi-media services are being integrated in tactical networks. Because each application has diverse Quality-of-service(QoS) requirements, it is crucial to develop a QoS provisioning method for guaranteeing QoS requirements efficiently. Conventionally, differentiated services(DiffServ) have been used to provide a different level of QoS for traffic flows. However, DiffServ is not designed to guarantee a specific requirement of QoS such as delay, loss, and bandwidth. Therefore, it is not suitable for military applications with a tight bound of QoS requirements. In this paper, we propose a multi-layer network virtualization scheme that allocates traffic flows having different QoS requirements to multiple virtual networks, which are constructed to support different QoS policies such as virtual network functions(VNFs), routing, queueing/active queue management(AQM), and physical layer policy. The experiment results indicate that the proposed scheme achieves lower delays and losses through multiple virtual networks having differentiated QoS policies in comparison with conventional networks.

• Journal of Communications and Networks
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• v.15 no.1
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• pp.61-70
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• 2013

The increasing number of mobile users and the popularity of real-time applications make wired-wireless integrated network extremely attractive. In this case, quality of service (QoS) adaptability is particularly important since some important features of the integrated network call for QoS adaptability, such as mobility, bursty applications and so on. Traditional QoS schemes include integrated service (IntServ) and differentiated service (DiffSev) as well as their variants. However, they are not able to balance well between scalability and QoS granularity. For example, IntServ faces the scalability problem, while DiffServ can only provide coarse granular QoS. In addition, they are also unable to efficiently support QoS adaptability. Therefore, a per-packet differentiated queueing service (DQS) was proposed. DQS was originally proposed to balance between scalability and QoS granularity in wired networks and then extended to wireless networks. This paper mainly discusses how to use DQS to support QoS adaptability in wired-wireless integrated networks. To this end, we propose a scheme to determine dynamic delay bounds, which is the key step to implement DQS to support QoS adaptability. Simulation studies along with some discussions are further conducted to investigate the QoS adaptability of the proposed scheme, especially in terms of its support of QoS adaptability to mobility and to bursty real-time applications.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.11b
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• pp.549-552
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• 2002

복잡하고 거대한 통신망을 효율적으로 구성하고 운용 관리하기 위해 ITU-T에서는 TMN 망관리 국제표준을 정하고 있다. 그러나 TCP/IP 기반의 인터넷 망에서는 TMN보다 간단하게 정의되어 있는 SNMP를 이용해 MIB를 기반으로 망 요소(network element) 제어만을 하고 있다. 인터넷 망에서 멀티미디어 데이터 교환 서비스를 수용하면서, IP 망 설계 초기에 고려하지 않았던 서비스품질(QoS)을 제공하기 위해 IntServ, DiffServ 프로토콜 등을 정의하고 있다. 이렇게 QoS를 제공하기 위한 인터넷 망은 단순한 SNMP 만으로는 관리될 수 없다. 그러나 아직까지 이에 적합한 망관리 모델이 정립되지 못한 상태인 바, 본 논문에서는 정책을 기반(policy-based)으로 하여 QoS 서비스를 위한 자원 할당을 dynamic하게 제공할 수 있도록 하는 QoS 인터넷 망관리 모델을 제안한다. 이 모델은 TMN의 관리계층 구조에 맞도록 구성되어 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1307-1310
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• 2004

네트웍이 고속화 됨에 따라 대용량 데이터를 실시간으로 전송/처리/저장하는 응용 분야가 등장하고 있다. 또한 전송 지연을 감소하고 신뢰도를 향상하기 위해서 많은 스토리지(storage) replica들이 네트웍에 설치되었다. 이러한 환경에서 응용 프로그램이 요구하는 성능을 만족하기 위해서는 네트웍 자원 뿐만 아니라 종단간 자원인 저장 매체의 선택/예약/관리를 함께 고려하는 통합적 분산 네트웍 스토리지(DNS: Distributed Network Storage) 시스템이 필요하다. 이러한 DNS에서 QoS를 제공하는 기존의 방식들은 크게 데이터그램(datagram) QoS, 클래스(class)별 차등적인 서비스를 제공하는 DiffServ QoS, 그리고 각 플로우(flow) 별 개별적인 서비스를 제공하는 IntServ QoS로 세분된다. 본 논문에서는 기존에 제안된 방식들을 비교 분석하여 각각의 장단점을 기술하며 향후 연구 문제들을 살펴본다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.6C
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• pp.571-580
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• 2002

In this paper, we relatively differentiate maximum delay for each Assured Service subclass in Differentiated Services by allocating bandwidth to each subclass differently. To maximize the throughput for the In-profile traffic and the link utilization, we propose a Cofiguration method of RIO and the admission control criterion based on the buffer size determined by the network topology and the ratio of bandwidth allocated to each subclass. Simulation results show that the proposed method can calculate the capacity to guarantee the QoS for the Assured Service and maximize the throughput for the In-profile traffic and the link utilization by applying the RIO parameter values set through the proposed configuration method.

• Journal of Communications and Networks
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• v.15 no.3
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• pp.301-311
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• 2013

This paper proposes a policy-based quality of service (QoS) management framework for adaptive routing decisions. We present an approach considering interior gateway protocol (IGP) for path discovery mechanisms and QoS-aware policies for configuring the network elements. The integration of the aforementioned modules into this policy-based network management (PBNM) system is demonstrated by conducting experiments in a real environment, the hellenic public administration network SYZEFXIS. These experiments combine different traffic conditioning mechanisms through event detectors, consider IP service level agreement mechanisms that interoperate with the PBNM system and analyze the enforcement of IGP and QoS policies. Finally, validation and measurement tools are used to prove the efficiency of this framework. It is shown that this architecture offers significantly increased performance and learning capabilities, while the PBNM system achieves adaptive QoS routing through automated configuration considering the avoidance of suboptimal routing issues or under-performance conditions of the network entities.

• ETRI Journal
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• v.27 no.6
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• pp.733-746
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• 2005

In the context of multi-protocol label switching (MPLS) traffic engineering, this paper proposes a scalable constraintbased shortest path first (CSPF) routing algorithm with multiple QoS metrics. This algorithm, called the multiple constraint-based shortest path first (M_CSPF) algorithm, provides an optimal route for setting up a label switched path (LSP) that meets bandwidth and end-to-end delay constraints. In order to maximize the LSP accommodation probability, we propose a link weight computation algorithm to assign the link weight while taking into account the future traffic load and link interference and adopting the concept of a critical link from the minimum interference routing algorithm. In addition, we propose a bounded order assignment algorithm (BOAA) that assigns the appropriate order to the node and link, taking into account the delay constraint and hop count. In particular, BOAA is designed to achieve fast LSP route computation by pruning any portion of the network topology that exceeds the end-to-end delay constraint in the process of traversing the network topology. To clarify the M_CSPF and the existing CSPF routing algorithms, this paper evaluates them from the perspectives of network resource utilization efficiency, end-to-end quality, LSP rejection probability, and LSP route computation performance under various network topologies and conditions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4B
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• pp.235-245
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• 2005

In this paper, a simplified QoS model of MPLS-based backbone network. Conventional scheme proposed by IETF(IETF schem) is to embed a DiffServ model in MPLS network. However, this approach results in overall upgrade of MPLS system and so it is difficult to deploy this approach. Our proposed model, however, uses a Vidual Link which is a set of Label Switched Path(LSP) connected from an Ingress Label Edge Router(LER) to an Egress LER. In this model, Per-Hop-Behavior(PHB) is implemented only at each LSP in ingress LER and Core Label Switch Routers(LSRs) just guarantee each LSP's bandwidth, not service. This bandwidth guarantee service is fully provided by legacy MPLS model. Also we propose flow allocation mechanism and the flow distribution among LSPs of the virtual link by the flow according to the network status. To evaluate the simplified approach, the characteristics of the approach are compared logically with these of IETF's one through simulations.