• Convergence Security Journal
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• v.23 no.1
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• pp.3-8
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• 2023

Multi-domain optical transport networks are not fundamentally interoperable and require an integrated orchestration mechanism and path provision mechanism at the entire network level. In addition, ensuring network survivability is one of the important issues. MPLS-TP (Multi-Protocol Label Switching-Transport Profile) defines various protection/recovery methods as standards, but does not mention how to calculate and select protection/recovery paths. Therefore, an algorithm that minimizes protection/recovery collisions at the optical circuit packet integrated network level and calculates and sets a path that can be rapidly protected/recovered over the entire integrated network area is required. In this paper, we proposed an algorithm that calculates and sets up a path that can be rapidly protected and restored in a T-SDN network composed of multiple ring-mesh topology.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.8
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• pp.949-956
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• 1999

이 논문에서는 ATM (Asynchronous Transfer Mode) 방식의 초고속망의 장애 발생 시 이용자 연결의 QoS (Quality of Service)를 고려하여 복구할 수 있게 하는 보호 망 설계 방안을 제시한다. 제시한 설계 방안에 기초한 비용과 복구 특성을 분석과 모의 실험을 통해 알아본다. 제안하는 망에서의 복구는 분리 VP 그룹 (Disjoint Virtual Path Group, DVPG) 을 사용하는 상태 독립적 (State- independent) 방식으로 복구된다. ATM 망의 운용 및 보호 VP 할당과 용량 배정 문제를 정의하고 이를 바탕으로 최소의 비용을 갖는 VP 망을 설계한다. 망의 고장 시 기존 노드간의 VP 연결은 미리 할당된 링크 또는 노드 분리 보호 VP 경로를 따라 간단한 복구 알고리즘에 의해 빠르게 복구된다. QoS의 고려는 추가 비용을 필요로 하지만 정확한 이용자 연결의 복구를 실현하며, 분리 VP 그룹의 적용은 비용을 상승시키지만, 빠른 복구와 복수의 고장에 대처할 수 있는 방안이 된다.Abstract A cost evaluation of protection scheme for VP-based ATM network is presented here and its related characteristics are evaluated. The proposed and evaluated scheme is a state-independent restoration scheme using a disjoint path group. For fast and simple restoration of failed connections, link disjoint or node disjoint VP groups (DVPG) were utilized in this paper. A VP assignment and capacity planning problem is formulated. When failure occurs, the failed working VPs are switched to the protection VPs of disjoint path groups with a simple restoration scheme. And, cost evaluation and restoration characteristics are presented. The consideration of multiple QoS (Quality of Service) levels and disjoint path group protection scheme require additional network cost but acquire fit and fast restoration.

• Proceedings of the Korea Society for Simulation Conference
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• 1997.04a
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• pp.66-71
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• 1997

생존 트래픽 비율로만 정의되는 기존의 생존도는 통신 재난시 트래픽의 상대적 중 요도와 복구기간에 대한 생존도를 적절히 반영하지 못한다. 따라서 트래픽의 상대적 중요도 에 따라 트래픽을 복구함으로써 재난의 사회적 영향을 최소화하고 복구기간을 반영하는 새 로운 평가척도로서 재난영향 평가척도를 제시한다. DCS 전송망에 대해 제시한 재난 영향 평가척도 및 기존의 생존도를 계산하기 위하여 통신재난 시나리오 분석 시스템을 이용한다. 통신재난 시나리오 분석 시스템[1]은 장애발생, 복구방법 및 복구과정 관련 시나리오등으로 구성되므로 DCS 전송망에 대한 생존도 계산이 가능하다. 통신재난 시나리오 분석 시스템을 이용하여 다양한 전송망에 대해 얻은 재난영향 평가척도 결과 및 기존 생존도 결과를 비교 하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.487-489
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• 2003

애드 혹 망은 유선 기반망 없이 무선 노드만으로 구성된 망을 말한다. 이러한 특징으로 인하여 빠른 망 구축을 가능하게 하지만, 망의 동적인 구조와 노드들의 이동성을 고려할 때 효율적인 데이터 전송을 위한 경로 유지는 중요한 문제로 대두된다. 본 논문에서는 애드 혹 라우팅 프로토콜 중의 하나인 AODV(Ad­hoc On­demand Distance Vector) 라우팅 프로토콜에서의 지역복구 (local repair) 시 경로설정 패킷의 플러딩 범위를 제한하는 범위 제한적(seeped) 플러딩을 이용한 효율적인 지역복구 기법을 제안한다. 이 방법의 경우 기존의 AODV 지역복구에 비해서 경로설정 오버헤드를 줄이고 데이터 전송률을 높일 수 있다.

• Journal of Internet Computing and Services
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• v.4 no.2
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• pp.1-9
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• 2003

Path restoration, which is needed to increase network survivability in MPLS networks, is a technology of supplying reliable service by delivering the traffics through restoring the paths when links or nodes of a working path are failed. In this paper, we propose a path restoration method using duplication of working paths for link failure as a method of restoring paths for the high priority traffics. The existing path restoration method transmits the traffics to the path restoration uniformly in regardless of the priority while link obstacle. It has a problem to take a long time to restore the connection of the high priority traffics. On the other hand, the suggested restoration method establishes the duplication path for the working path, which transmits the high priority traffics and transmit the traffics through the duplication path. It has a strong point to restore the connection quickly. Also, through simulation we analyze the performance of the restoration system using the duplication path and prove that the proposed restoration method is superior in performance to the existing restoration methods regarding to the high priority traffics.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.11
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• pp.49-58
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• 2010

In this paper, we present a methodology for fast segment restoration under multiple simultaneous link failures in mesh-type MPLS networks. The salient feature of the methodology is that both resilience and QoS constraint conditions have been taken into account for fast segment restoration. For fast restoration, a sufficient condition for testing the existence of backup segments with guaranteed-resilience has been derived for a mesh-type MPLS network. The algorithms for constructing backup segments which can meet both resilience and QoS constraint conditions are then presented with illustrating examples. Finally, simulation has been done to show the efficiency of the proposed segment restoration algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11B
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• pp.956-966
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• 2004

Nowadays, NGN(Next Generation Network) is evolving into network with packet based QoS.\ulcorner This paper presents the recovery method as a selecting way of more efficient path in MPLS network that reduces the service interruption time. In order to increase the efficiency of usage of recovering resource which is one of major functions of disorder recovering, it opens the state information of each Node both to fault detector and bandwidth broker so that it reduces message transmission time for recovery when functional disorder occurs. in addition, by effective management and adjustment of required bandwidth of entire network depending on the changes of traffic load, it improves the efficiency of bandwidth usage. and in MPLS network supporting priority selection function, it allocates domains depending on the traffic relating to priority order to the entire network so that\ulcorner it efficiently allocates proper resources to the restoring process between the entry and the end for the traffic of high priority and for low priority traffic, it restores path oかy inside disordered domain. by doing this, it reduces resetting time and unnecessary massage transmission.

• Information and Communications Magazine
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• v.15 no.5
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• pp.88-98
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• 1998

지금까지 ATM 망의 생존도에 대하여 연구되어 온 관련 모형 및 알고리듬은 주로 가상 경로의 특징을 제대로 적용하지 않고, 기존의 STM 망 모형의 변형을 이용한 연구가 대부분이었다. 또한 장애가 일어났을 때 ATM의 OAM 셀을 사용해 장애를 어떻게 효율적으로 알리고 복구 확인을 하는 차원의 연구가 많은 반면, 복구가 망 전체 차원에서 어떻게 자원을 최적화로 사용하고 관리 및 계획의 객체를 정의할 지 등에 대한 체계적인 연구나 모형화가 시작되지 못해왔다. 이 논문에서는 ATM 망의 가상경로 개념을 사용한 생전도 확보 기법에 대하여 지금까지의 연구 동향 및 향후 연구방향에 대하여 기술한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.9B
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• pp.793-805
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• 2003

In OBS (Optical Burst Switching) networks which decouple the burst from its header, the fault of a fiber link can lead to the failure of all the light-path that traverses the fiber. Because each light-path is expected to operate at a rate of a few Gbps by using WDM (Wavelength Division Multiplexing) technology, any failure may lead to large data loss. Therefore, an efficient recovery scheme must be provided. In this paper, we analyze network utilization and BCP (Burst Control Packet) loss rate according to each link failure by applying the conventional restoration schemes in OBS networks. And through these simulation results, an ASPR scheme is proposed improve the fault management scheme in terms of recovery time and throughput. Finally, We compare the performance of our proposed scheme with that of the conventional one with respect to burst loss rate, resource utilization and throughput by OPNET simulations.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.3
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• pp.259-269
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• 2020

With the proposal-agreement procedure, RSTP can reduce the network recovery time to 400 ms or less in the case of 40 bridges. While the legacy RSTP reverts the previous agreement at the bridge with the alternate port role in the ring during the fault recovery, a new position based fast fault recovery procedure is proposed in this paper to guarantee a single proposal-agreement transaction which can provide more faster recovery. By knowing the relative position of the faulty link or bridge in hops, the bridge on the middle of the ring can complete the recovery procedure without revert. The performance of proposed procedure is numerically calculated and verified by simulation and the result shows that the recovery time can be reduced up to 100 ms, which is 1/4 times of the legacy RSTP.