• Journal of Communications and Networks
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• 제9권4호
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• pp.408-418
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• 2007

In this paper, we address the question of dynamic network provisioning for time-varying traffic rates, with the objective of maximizing the system throughput. We assume that the network is capable of providing bandwidth guaranteed traffic tunnels for an ingress-egress pair and present an approach that (1) updates the tunnel routes and (2) adjusts the tunnel bandwidths, in an incremental, adaptive manner, based on the variations in the incoming traffic. First, we consider a simpler scenario where tunnel routes are fixed, and present an approach for adjusting the tunnel bandwidths dynamically. We show, through simulations, that our dynamic bandwidth assignment algorithm significantly outperforms the optimal static bandwidth provisioning policy, and yields a performance close to that of the optimal dynamic bandwidth provisioning policy. We also propose an adaptive route update algorithm, which can be used in conjunction with our dynamic bandwidth assignment policy, and leads to further improvement in the overall system performance.

• 한국정보과학회논문지:정보통신
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• 제31권5호
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• pp.501-510
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• 2004

인터넷이 인간 삶의 모든 양상에 영향을 미치게 되면서 중요한 2가지 요구사항이 나오게 되었다. 하나는 멀티미디어 데이타 서비스 지원을 위해 높은 서비스 질(QoS)에 대한 요구이고 또 다른 하나는 유비쿼터스(Ubiquitous) 네트워크 연결을 위한 요구이다. 이러한 2가지 요구사항을 만족시킨다는 것은 인터넷이 이동하는 노메딕(Nomadic) 사용자들에게 멀티미디어 통신 지원을 가능하게 한다는 것이다. 현재 Mobile IP 메커니즘에 RSVP 적용을 통해 이동 사용자들에게 QoS 통신을 지원하는 방안으로 흠 에이전트와 외부 에이전트 사이에 RSVP를 위한 별도의 세션을 두는 방법을 명세화하는 RSVP Tunnel이 제안되었다. 그러나 이 RSVP Tunnel은 중복된 RSVP 메시지 사용으로 인해 터널에서의 대역폭 오버헤드와 메시지들 사이의 관계 문제를 야기 시킨다. 본 논문에서는 이러한 문제를 해결하기 위해 Mobile If 망에 서 효과적으로 QoS를 보장할 수 있는 새로운 캡슬화 방법인 RSVP-in-IP Encapsulation(RIPE)를 제안한다. 제안된 방법은 RSVP Tunnel 방법과 같은 어떠한 세션의 추가없이 효과적으로 Mobile IP 터널링 메커니즘에 RSVP 이동성을 보장할 뿐만 아니라 터널에서의 대역폭 오버헤드 문제와 중복 메시지들 사이의 관계 문제도 해견한다. 성능 평가는 기존 관련연구에서 제안된 RSVP Tunnel과 RIPE에 대해 평균지연, 평균 데이타비율, 터널에서의 대역폭 오버헤드 등의 성능지표를 가지고 시뮬레이션을 통해 수행되었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1846-1850
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• 2005

This paper presents a constrained-based routing (CBR) algorithm called, Dynamic Possible Path per Link (D-PPL) routing algorithm, for MultiProtocol Label Switching (MPLS) networks. In MPLS on-line routing, future traffics are unknown and network resource is limited. Therefore many routing algorithms such as Minimum Hop Algorithm (MHA), Widest Shortest Path (WSP), Dynamic Link Weight (DLW), Minimum Interference Routing Algorithm (MIRA), Profiled-Based Routing (PBR), Possible Path per Link (PPL) and Residual bandwidth integrated - Possible Path per Link (R-PPL) are proposed in order to improve network throughput and reduce rejection probability. MIRA is the first algorithm that introduces interference level avoidance between source-destination node pairs by integrating topology information or address of source-destination node pairs into the routing calculation. From its results, MIRA improves lower rejection probability performance. Nevertheless, MIRA suffer from its high routing complexity which could be considered as NP-Complete problem. In PBR, complexity of on-line routing is reduced comparing to those of MIRA, because link weights are off-line calculated by statistical profile of history traffics. However, because of dynamic of traffic nature, PBR maybe unsuitable for MPLS on-line routing. Also, both PPL and R-PPL routing algorithm we formerly proposed, are algorithms that achieve reduction of interference level among source-destination node pairs, rejection probability and routing complexity. Again, those previously proposed algorithms do not take into account the dynamic nature of traffic load. In fact, future traffics are unknown, but, amount of previous traffic over link can be measured. Therefore, this is the motivation of our proposed algorithm, the D-PPL. The D-PPL algorithm is improved based on the R-PPL routing algorithm by integrating traffic-per-link parameters. The parameters are periodically updated and are dynamically changed depended on current incoming traffic. The D-PPL tries to reserve residual bandwidth to service future request by avoid routing through those high traffic-per-link parameters. We have developed extensive MATLAB simulator to evaluate performance of the D-PPL. From simulation results, the D-PPL improves performance of MPLS on-line routing in terms of rejection probability and total throughput.