• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2249-2261
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• 1999

In this paper, we describe the design and implementation of the Label Distribution Protocol (LDP) for Multiprotocol Label Switching System. We review the implementation issues of LDP that is required to make a gigabit switched router, and propose a detail design of it. We present the data structures and procedures for the LDP as a result, which are based on IETF standard. We present design issues for applying this to carrier class products. The implemented protocol could afford 40,000 entries of the IP routing table that is required for deploying this system to commercialized data network. Furthermore this system implemented using the standard API of Unix, as a result, it has portability. By implementing LDP based on the international standard and these implementation issues, we expect that the implemented LDP will be interoperable with other commercialized products. We prove the validity of the design of the LDP through prototyping, and also verify the prototype with the specification using the process algebra and the performance analysis.

• Journal of KIISE:Information Networking
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• v.31 no.2
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• pp.233-241
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• 2004

In this paper, we propose a packet-lossless fast rerouting scheme at a link/node fault in MPLS (Multiprotocol Label Switching) network with minimized accumulated buffer delay problem at ingress node. The proposed scheme uses a predefined, alternative LSP (Label Switched Path) In order to restore user traffic. We propose two restoration approaches. In the first approach, an alternative LSP is initially allocated with more bandwidth than the protected working LSP during the failure recovery phase. After the failure recovery, the excessively allocated bandwidth of the alternative LSP is readjusted to the bandwidth of the working LSP. In the second approach, we reduce the length of protected working LSP by using segment-based restoration. The proposed approaches have merits of (ⅰ) no buffer delay problem after failure recovery at ingress node, and (ⅱ) the smaller required buffer size at the ingress node than the previous approach.

• Journal of Communications and Networks
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• v.11 no.3
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• pp.297-305
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• 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.

• The Journal of Information Technology
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• v.5 no.4
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• pp.155-164
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• 2002

MPLS is a integrated technology by using routing function and label swapping in the network layer. Based on the previous forwarding equivalence classes, it adds the fixed length label in ingress of the MPLS domain. For the routing, without the packet header information, it uses label for the forwarding decisions. In this paper, traffic engineering requirements in the MPLS internet will be setup. The traffic engineering function have to be performed previously with the network topology. In addition to, we presents the IP network topology and main function with MPLS signaling protocol.

• Electronics and Telecommunications Trends
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• v.15 no.5 s.65
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• pp.41-48
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• 2000

MPLS(Multiprotocol Label Switching)를 이용한 IP 기반의 VPN은 고수익을 원하는 서비스제공자들과 저비용을 원하는 기업들에게 인트라넷(intranet)과 익스트라넷(extranet)의 해결책으로서 많은 관심을 끌고 있다. MPLS VPN에 대한 표준화는 IETF에서 추진되고 있는데, BGP multiprotocol extension(BGP-E)이라는 프로토콜을 이용하는 구조와 Virtual Router(VR)라는 개념을 이용하는 구조가 제안되었다. BGP-E 방식은 시스코에 의해 제안되어 RFC2547로 채택되었다. 이 방식에서는 BGP-E를 이용하여 도달성과 멤버쉽 정보를 PE간에 교환한다. VR 방식은 노텔과 루슨트를 중심으로 여러 기업들이 지지하고 있고 드래프트 형태로 작업중이다. 이 방식에서는 PE들에 VPN별로 VR들을 배치하고 같은 VPN에 속하는 VR들끼리 기존의 라우팅 프로토콜을 이용하여 라우팅 정보를 교환한다. 두 방식의 근본적 차이는 도달성과 멤버쉽 메커니즘의 분리 여부이다. 세계적으로 이름 있는 통신 회사들이 경쟁적으로 MPLS 시스템을 개발하고 있는 상황에서 MPLS VPN 기술도 빠르게 시장에 확산될 것으로 전망된다. 그러나 서로 다른 기술적 접근을 하고 있는 서비스제공자들간의 MPLS VPN에 대한 호환성은 시급히 풀어야 할 숙제로 남아 있다.

• Journal of KIISE:Information Networking
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• v.30 no.2
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• pp.270-281
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• 2003

ETF made the RFCs of MPLS technologies for providing the QoS of ATM or Frame Relay and the flexibility&scalability of IP on the Internet services. IETF has been expanding MPLS technologies as a common control component for supporting the various switching technologies called GMPLS. Also, IETF has standardized the signaling protocols based on such technologies, such as LDP, CR-LDP and RSVP-TE. ETRI developed the MPLS system based on ATM switch in order to provide more reliable services, differentiated services and value-added services like the VPN and traffic engineering service on the Korea Public Sector network. We are planning on deploying model services and commercial services on that network. This paper explains the basic functions of LDP, design and development of LDP on our system, and compares with LDP development and operation on other MPLS systems made by Cisco, Juniper, Nortel and Riverstone. In conclusion, this paper deduces the future services and applications by LDP through these explanation and comparison.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.61-64
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• 2007

MPLS networks architectures have been prevailed as scalable approach to provide quality of service in the Internet. Many researches have been mainly focused on scalability and multi-path calculation scheme for failure restoration. However, the MPLS network have an scalability problem about traffic, and the existing failure restoration methods are wasted resources, and it has the problem that loss of a packet by a lot of delay occurs in too. Therefore in this paper, we propose a H-MPLS (Hierachical-Multiprotocol Label Switching)network for rapidly failure restorations and effective management of network extended. The proposed H-MPLS Network apply LSP multi-path routing algorithm and consists of several MPLS. After comparing the performance among the existing failure restoration methods with various network models, we use NS simulator in order to analyze the performance. Finally, we present an improvement scheme of the efficiency and scalability.

• The KIPS Transactions:PartC
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• v.10C no.1
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• pp.77-86
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• 2003

This paper describes the new method for Internet multicast routing protocols using MPLS (Multiprotocol Label Switching) networks. Internet multicast routing protocols are divided into three categories in terms if tree types and tree characteristics : a shortest path tree a shared tree and hybrid tree types. MPLS should support various multicast mechanisms because of extremely different IP multicast architectures, such as uni-/bi-directional link, Flooding/prune tree maintenance mechanism. the existence of different tree types with the same group, etc. There are so many problems over MPLS multicast that the solutions can't be easily figured out. In this Paper, we make a few assumptions on which the solutions of IP multicast routing protocols over MPLS networks are given. A broadcasting label is defined for the shortest path tree types. Cell interleaving problems of the shared tree types is solved by using block-based transmission mechanism. Finally, the existing hybrid-type multicast routing protocol is reasonably modified Shortest Path tree type to support MPLS multicast. It has been shown that these modifications give better performance (transmission delay) than the orignal method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.59-65
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• 2015

To build a flexible network than traditional transport network, the carrier ethernet technology is emerging in network industry recently and MPLS-TP technologies are being applied as a major standard technology for the carrier ethernet. However, network management technologies required to handle equipment installed in MPLS-TP network are not clear. This paper propose an efficient method to build a management network automatically without any additional configuration when network equipments are installed in MPLS-TP network. The proposed scheme reduce cost required for both equipment installation and network maintenance by minimizing configuration procedures of connecting management system with network. We evaluated the effectiveness of the proposed scheme by applying the scheme to a real MPLS-TP equipment.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.3
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• pp.93-103
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• 2000

This paper describes Internet multicast routing protocols over MPLS (Multiprotocol Label Switching) networks. Internet multicast routing protocols are divided into 3 categories in terms of tree types and tree characteristics: a shortest path tree, a shared tree and hybrid tree types. MPLS should support various multicast mechanisms because of extremely different IP multicast architectures, such as uni-/bi-directional link, Flooding/prune tree maintenance mechanism, the existence of different tree types with the same group, etc. There are so many problems over MPLS multicast that the solutions can't be easily figured out. In this paper, we make a few assumptions on which the solutions of IP multicast routing protocols over MPLS networks are given. A broadcasting label is defined for the shortest path tree types. Cell interleaving problems of the shared tree types is solved by using block-based transmission mechanism. Finally, the existing hybrid-type multicast routing protocol is reasonably modified to support MPLS multicast.