• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.5
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• pp.53-61
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• 2004

This paper proposes two types of sub-network based on dynamic restoration schemes to improve survivability of GMPLS networks and analyzes characteristics of these two schemes. The first proposed scheme divides with a whole GMPLS network into several sub-networks, applies a mixture of both restoration and protection methods according to fault location. The other scheme divides a whole GMPLS network into primary and secondary sub-networks, applies a restoration method in each sub-network according to fault location. In our simulation, we evaluate the performances of network resource utilization, restoration success rate, and mean restoration time and conduct its comparative analysis with conventional schemes. The simulation results show that the efficiency of network resource utilization in the proposed schemes is increased as compared with conventional restoration schemes (l＋l, 1:1, 1:N) in case of single-failed link. By contrast, we found that the performances of restoration success rate and mean restoration time in case of multi-failed link is lower than conventional restoration schemes. However, the probability that multi-failed link is occurred is very low so that the problem in practical GMPLS network is negligible.

• International Journal of Contents
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• v.5 no.2
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• pp.43-52
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• 2009

The article first presents a broad overview of the design and management for survivable network. We review the concept of network survivability, various protection and restoration schemes. Also we introduce design architectures of Quantitative model and a Survivable Ad hoc and Mesh Network Architecture. In the other side of study like these(traditional engineering approach), there is the concept of the survivable network systems based on an immune approach. There is one sample of the dynamic multi-routing algorithms in this paper.

• Journal of Communications and Networks
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• v.8 no.2
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• pp.228-233
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• 2006

Survivability is a very important requirement for the deployment of broadband networks because out of service links can affect volumes of traffic even if it is a very short time. And the data paths of broadband networks, which are critical for traffic engineering, are always necessary to be well protected. The procedure of protection or restoration for a path is initiated when failure is detected within the working path. In order to minimize the influence on transmission quality caused by the failure of links and to provide a definite time for the recovery from the failure, the protection switching time (PST) should be carefully considered in the path arrangement. Several researches have been devoted to construct the protection and restoration schemes of data paths over dense wavelength division multiplexing (DWDM) networks, however, there was rare research on the design of data paths with guaranteed protection switching time. In this paper, the PST-guaranteed scheme, which is based on the concept of short leap shared protection (SLSP), for the arrangement of data paths in DWDM networks is proposed. The proposed scheme provides an efficient procedure to determine a just-enough PST-guaranteed backup paths for a working path. In addition to selecting the PST-guaranteed path, the network cost is also considered in a heuristic manner. The experimental results demonstrate that the paths arranged by the proposed scheme can fully meet the desired PST and the required cost of the selected path is competitive with which of the shared path scheme.

• Journal of Communications and Networks
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• v.9 no.2
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• pp.198-209
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• 2007

This paper provides a thorough study on shared segment protection (SSP) for mesh communication networks in the complete routing information scenario, where the integer linear program (ILP) in [1] is extended such that the following two constraints are well addressed: (a) The restoration time constraint for each connection request, and (b) the switching/merging capacity constraint at each node. A novel approach, called SSP algorithm, is developed to reduce the extremely high computation complexity in solving the ILP formulation. Basically, our approach is to derive a good approximation on the parameters in the ILP by referring to the result of solving the corresponding shared path protection (SPP) problem. Thus, the design space can be significantly reduced by eliminating some edges in the graphs. We will show in the simulation that with our approach, the optimality can be achieved in most of the cases. To verify the proposed formulation and investigate the performance impairment in terms of average cost and success rate by the additional two constraints, extensive simulation work has been conducted on three network topologies, in which SPP and shared link protection (SLP) are implemented for comparison. We will demonstrate that the proposed SSP algorithm can effectively and efficiently solve the survivable routing problem with constraints on restoration time and switching/merging capability of each node. The comparison among the three protection types further verifies that SSP can yield significant advantages over SPP and SLP without taking much computation time.

• 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.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.612-615
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• 2007

The environmental damage caused by river-improvement and slope of incision cliff can dest habitations of animate nature and it takes long time for restoration. River system constructed with stability of flood control, fine biotope, harmony with surroundings should be need to protect and restore nature. Therefore, in this study, conduct comparative experiment in various methods which are stable hydraulically and develop vegetation on revetment of bank, stream bed protection and disaster prevention aspect.

• 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.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1620-1622
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• 1998

The failure occurs in the system of the underground transmission line, the time of restoration is very long, the damage from stopping power supply is very serious and the cost of restoration is very great. because of these problems, the system and equipment must be protected from every electrical failure by installing protection unit. This study is summarized and compared the effects of configuration method of cable protection device with respect to surges in EHV (Extra High Voltage) underground transmission system.

• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.448-460
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• 2003

In this paper, we propose a network fault recovery algorithm based on a segment restoration scheme to reduce restoration time and restoration resource. The proposed segment restoration scheme is based on network partitioning which divides a large network into several small subnetworks. The restoration performance of the proposed segment restoration scheme depends on the size and the topology of subnetworks. Since most faults can be restored in a subnetwork, restoration time is reduced obviously. We compare and analyze restoration performance according to the size of subnetworks and restoration schemes. From simulation results, the proposed segment restoration scheme has the shortest restoration time compared with other restoration schemes. Especially the restoration performance of the proposed segment restoration scheme is better than the SLSP, which is also a segment-based restoration scheme, in terms of restoration time and required restoration resource capacity.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.1
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• pp.1-10
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• 2011

The purpose of this study is to derive the actually applicable directions and measures for conservation and restoration according to biotope types. Recently biotope project-installing eco-river, restoring damaged area, protecting habitate for flora and fauna- is processed according to being interested in making and restoring the biotope. But it is lack of study to estimate and systematize which biotope preserve and restore primary. For this purpose, the direction and measures of conservation and restoration be applicable to actuality are drafted by a review on the preceded case studies until now at the inside and outside of the country. And then this study proposed the concept, direction and measures for the effective systematic biotope management through continual feed back such as field applications in selected case study areas and consultations. First, the applicable directions and measures for conservation and restoration according to biotope types is suggested with the 'conservation' divided into two parts; protection and maintenance, the 'restoration', and the 'enhancement' divided into two parts; improvement and creation. Second, for the effective biotope management, the biotope types are classified into urban type, agricultural types and natural types according to the naturalness and dominant landscape. However, this study suggests that the direction and measures suitable to the regional conditions should be reviewed enough and selected and also the detail measures should be supplemented with the foundation of directions and measures for biotope conservation and management proposed in this study because the biotope management should consider regional characteristics.