• Journal of Communications and Networks
• /
• 제11권3호
• /
• pp.297-305
• /
• 2009

Multiprotocol label switching (MPLS) networks require dynamic flow admission control to guarantee end-to-end quality of service (QoS) for each Internet protocol (IP) traffic flow. In this paper, we propose to tackle the joint routing and admission control problem for the IP traffic flows in MPLS networks without rerouting already admitted flows. We propose two mathematical programming models for this problem. The first model includes end-to-end delay constraints and the second one, end-to-end packet loss constraints. These end-to-end QoS constraints are imposed not only for the new traffic flow, but also for all already admitted flows in the network. The objective function of both models is to minimize the end-to-end delay for the new flow. Numerical results show that considering end-to-end delay (or packet loss) constraints for all flows has a small impact on the flow blocking rate. Moreover, we reduces significantly the mean end-to-end delay (or the mean packet loss rate) and the proposed approach is able to make its decision within 250 msec.

• 한국통신학회논문지
• /
• 제29권1B호
• /
• pp.64-72
• /
• 2004

Multiprotocol Label Switching (MPLS) has been developed as a key technology to enhance the reliability, manageability and overall quality of service of core If networks with connection-oriented tunnel LSP and traffic engineering such as constraint-based routing, explicit routing, and restoration. In this paper, we propose a control bandwidth borrowing scheme that maximizes the utilization of tunnel LSPs or physical links by an extension to the RSVP-TE label distribution protocol. MPLS-based core switching network and VPN services rely on the establishment of connection-oriented tunneled LSPs that are configured or predefined by network management systems. The mechanism of network management system varies from (i) a relatively static LSP establishment accounting, to (ii) a dynamic QoS routing mechanisms. With the use of hierarchical LSPs, the extra bandwidth that is unused by the trunk (outer) LSPs should be fully allocated to their constituent end-to-end user traffic (inner) LSPs in order to maximize their utilization. In order to find out the unused extra bandwidth in tunnel LSP or physical link and redistribute these resources to constituent LSPs, we expend the functionality of RSVP-TE and the found unused extra bandwidth is redistributed with a weight-based recursive redistribution scheme. By the extended RSVP-TE and proposed recursive redistributed scheme, we could achieve the instantaneous maximized utilization of tunnel LSP or physical link suffering from the potential under-utilization problem and guarantee the end-to-end QoS requirements. With the proposed scheme, network manager can manage more effectively the extra available bandwidth of hierarchical LSPs and maximize the instantaneous utilization of the tunneled LSP resources.

• 한국정보통신학회논문지
• /
• 제5권7호
• /
• pp.1272-1279
• /
• 2001

최근 공중통신망은 다양한 서비스 요구사항의 변화와 ATM, MPLS 및 DWDM 등의 새로운 전달망 기술의 발달과 같은 통신 파라다임의 변화로 인하여 개방형 구조의 초고속 통합 패킷 통신망 구조를 갖는 차세대 통신망으로 진화하고 있다. 그러나 차세대 통신망에서도 기존의 음성서비스는 통신사업자 관점에서 중요 서비스로 계속적인 기술 개발이 연구되고 있다. 본 논문에서는 차세대 통신망에 적용하여 기존의 음성서비스 백만 아니라 다양한 신규 서비스들을 수용할 수 있는 media gateway에서 효율적인 대역관리 방법을 제안한다.

• Journal of Communications and Networks
• /
• 제7권3호
• /
• pp.377-384
• /
• 2005

The purpose of this research is to develop and evaluate a traffic engineering architecture that uses local state information. This architecture is applied to an Internet protocol radio access network (RAN) that uses multi-protocol label switching (MPLS) and differentiated services to support mobile hosts. We assume mobility support is provided by a protocol such as the hierarchical mobile Internet protocol. The traffic engineering architecture is router based-meaning that routers on the edges of the network make the decisions onto which paths to place admitted traffic. We propose an algorithm that supports the architecture and uses local network state in order to function. The goal of the architecture is to provide an inexpensive and fast method to reduce network congestion while increasing the quality of service (QoS) level when compared to traditional routing and traffic engineering techniques. We use a number of different mobility scenarios and a mix of different types of traffic to evaluate our architecture and algorithm. We use the network simulator ns-2 as the core of our simulation environment. Around this core we built a system of pre-simulation, during simulation, and post-processing software that enabled us to simulate our traffic engineering architecture with only very minimal changes to the core ns-2 software. Our simulation environment supports a number of different mobility scenarios and a mix of different types of traffic to evaluate our architecture and algorithm.

• ETRI Journal
• /
• 제27권6호
• /
• pp.733-746
• /
• 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.

• 한국정보통신설비학회:학술대회논문집
• /
• 한국정보통신설비학회 2006년도 하계학술대회
• /
• pp.145-150
• /
• 2006

For most of the measuring methods of traditional control theory, measuring equipments are located at the output of the system to measure quantities transformed from non-electrical form into electrical one. This method helps us to define the value of parameters to be measured, but it has limitation because it can only assess the efficiency of a movement process. That means we can not understand the inner kinetics which is the essence of the system. In the modern control theory, states of system are considered as the feedback to the control process, which helps us to assess the elements in the inside of the system. In this paper, we survey methods for estimating states being not exposed to the correct measurements. Using this method, we also suggest an application for giving an estimate of the traffic on the LSPs to adapt the network configuration for changing traffic conditions.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2013년도 춘계학술대회
• /
• pp.491-493
• /
• 2013

본 논문에서는 표준화 전략 수립을 위해 패킷광브로드밴드의 표준화 대상을 Ethernet/MPLS-TP 기반 패킷 전달 기술(IEEE 802, IETF), PON 기반 광 가입자 망 기술(ITU-T), OTN 기반 광 전달망 기술(ITU-T), Ethernet 기반 데이터 센터 기술(IEEE 802)로 구분하고 이들 기술들에 대한 국내 표준화 추진 대상 및 전략을 알아 보고자 한다.

• Journal of Communications and Networks
• /
• 제9권4호
• /
• pp.377-382
• /
• 2007

This paper presents a new enhanced dynamic and multilayer protection(DMP) routing scheme that considers cooperation between packet and wavelength switching domain in order to minimize the resource consumption. The paper describes the architecture of the multilayer network scenario and compares the proposed algorithm with other routing mechanisms applying protection at the IP/multi-protocol label switching(MPLS) layer or at the optical layer. Simulation results show that DMP reduces the number of optical-electrical-optical(o-e-o) operations and makes an efficient use of the network resources compared to non-multilayer proposals.

• 한국정보과학회논문지:정보통신
• /
• 제34권1호
• /
• pp.1-15
• /
• 2007

모바일 기기의 다양화와 무선 기술의 발전으로 모바일 사용자가 증가함에 따라, 이들을 위한 효율적이고 안전한 VPN(Virtual Private Network) 접속 및 관리가 중요한 이슈가 되고 있다. 이에, 본 논문에서는 모바일 VPN 사용자가 서로 다른 사이트에 있는 하나 이상의 사용자와 효율적으로 통신할 수 있도록 하는 PE(Provider Edge) 기반 PP(Provider Provisioned) 모바일 VPN 메커니즘을 제안한다. 제안하는 방안은 모바일 VPN 사용자의 IPSec 터널 오버헤드를 최소화했을 뿐만 아니라, 모바일 VPN 사용자의 위치에 관계없이 추가적인 IPSec 터널 오버헤드를 발생하지 않고 모바일 VPN 사용자 및 정적 VPN 사용자 간 최적화된 경로로 트래픽을 전달할 수 있도록 한다. 제안한 구조 및 프로토콜은 RFC2547에 제시된 'BGP/MPLS VPN' 기술을 기반으로 한다. 제안하는 방안에서는 모바일 VPN 사용자가 외부네트워크로 이동했을 때, BGP/MPLS VPN 서비스를 모바일 VPN 사용자까지 확대하기 위해 서비스 제공자 측에 PNS(PPVPN Network Server)를 새로이 정의하였다. 제안하는 방안은 사용자 기반 모바일 VPN 및 CE 기반 모바일 VPN과 비교하여 IPSec 터널 관련한 오버헤드가 더 적으며, 시뮬레이션 결과, CE 기반 모바일 VPN 방안에 비하여 종단간 패킷 지연에 있어서 더 우수한 성능을 보임을 알 수 있었다.

• ETRI Journal
• /
• 제25권5호
• /
• pp.369-378
• /
• 2003

Using the general switch management protocol on a multi-protocol label switching network, we present an efficient method for handling handovers. The proposed method directly changes an established path into a new path for supporting a handover. Our investigation reveals the effects of the proposed scheme and demonstrates that this method significantly reduces signaling costs and delays.