• Title/Summary/Keyword: OSPF

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A Study on OSPF for Wireless Tactical Communication Networks (무선 전술 통신망을 위한 OSPF 적용 방안)

  • Kook, Sung-Sook;Chang, Moon-Jeong;Lee, Mee-Jeong;Jun, Je-Hyun;Kim, Tae-Wan;Choi, Jeung-Won;Roh, Bong-Soo
    • Journal of KIISE:Information Networking
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    • v.37 no.2
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    • pp.109-121
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    • 2010
  • Recently, the military of Korea has been establishing the next generation wireless tactical communication system so called Tactical Information Communication Network (TICN). A routing protocol for TICN transport networks has to be able to select a path with high survivality, reliability, and stability while accommodating as many flows as possible with minimum QoS guarantees. The OSPF(Open Short Path First) used widely is determined to be the routing protocol for TICN. With the typical deployment practices OSPF, however, it cannot satisfy the requirements of TICN. In this paper, we propose a cost function for OSPF and a way to tune the OSPF protocol parameters for the TICN transport networks. Through simulations, it is shown that the OSPF with the proposed cost function provides better performance than the OSPF in terms of both the services provided to the applications and the network resources utilization.

Algebraic Formal Specification and Formal Validation of the Standard and an Implementation of the OSPF Protocol (OSPF Protocol 표준 및 구현의 대수 정형적 명세 및 정형적 검증)

  • 박재현
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.3B
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    • pp.360-374
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    • 2004
  • The OSPF protocol is the most widely used Interior Gateway Routing Protocol. Therefore, for the reliability of behavior of gigabit swiching routers, it is essential to guarantee the interoperability and the safety of the OSPF protocol. In this paper, we analyze the standard document of the OSPF protocol, so that we provide a formal specification that specifies the protocol behaviors by detailed design level using the algebraic formal method. By referring available source codes of the OSPF protocol, we supplement the formal specification to express more detailed behaviors that is not specified definitely in the standard. We also formally verify the interoperability and the safety of the protocol state machine of the specification. By showing that the formal specification specify all of the states and the transition events that appear in the standard document of the OSPF protocol, we prove that the state machine has the completeness, and prove it has the interoperability. To prove that the specification of the protocol has the safety, we formally verify the reachability, the liveness, the livelock-free property, and the deadlock-free property. As a result, we prove the protocol has the consistency. The specification and the validation are also effective to the OSPF Version 3 that inherit the protocol mechanism of the OSPF Version 2.

A Study on OSPF for Active Routing in Wireless Tactical Communication Network (전술통신망에서 능동적 라우팅을 위한 OSPF에 대한 연구)

  • Lee, Seung-Hwan;Lee, Jong-Heon;Lee, Hoon-Seop;Rhee, Seung-Hyong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.12B
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    • pp.1211-1218
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    • 2010
  • OSPF is the optimized routing protocol in wired network and considered as a tactical routing protocol in wireless tactical communication network. However because it is designed basically based on wired environment, it runs inadequately in wireless tactical environment: noise and jamming signal. So, we proposed new OSPF cost function to develop active routing protocol in wireless tactical communication network. In redefined cost function, there are four parameters that are relative transmission speed, link weight, router utilization, link average BER(Bit Error Rate). These parameters reflect wireless tactical characters. Also, we remodel the option field in Hello packet. It can help user to periodically check the link state. From the simulation result, it is shown that proposed OSPF is better than OSPF in jamming situation and has accumulative delay gain with dispersion of traffic load in entire network.

Packet Processing Analysis of OSPF Routing Protocol (OSPF라우팅 프로토콜의 패킷 처리 분석)

  • 최승한;주성순
    • Proceedings of the IEEK Conference
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    • 2000.11a
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    • pp.477-480
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    • 2000
  • Open Shortest Path First(OSPF) is a dynamic, hierarchical routing protocol designed to support routing in TCP/IP networks. Currently, OSPF is used as Interior Gateway Protocol(IGP) in many routers. In this paper, we analyze the variation of number of OSPF routing packets in case of changing the network configuration. The results show that the number of packets in case of adding new link increase five times than one in case of normal operation.

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Study on OSPF Routing Cost Functions for Wireless Environments (무선 환경을 고려한 OSPF 라우팅 비용함수 연구)

  • Shin, Dong Wook;Lee, Seung Hwan;Rhee, Seung Hyong;Lee, Hyung-Joo;Hoh, Mi-Jeong;Choi, Jeung-Won;Shin, Sang-Heon;Kim, Tae-Wan;Moon, Ho-Won
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37C no.9
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    • pp.829-840
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    • 2012
  • Recently, in network communication environments, it is changing very fast from wired to wireless. The open shortest path firtst (OSPF), one of link state routing protocols, mainly used in wired networks, is the routing method to select optimal traffic path as identifying the link state of neighbor routers. The traditional OSPF cost functions performs with first fixed cost permanently, unless the router link is changed. However, in wireless networks, the performance of links show big difference by other environment factors. The bit error rate (BER), a parameter which can quite affect link state in wireless networks, is not considered in the traditional OSPF cost functions. Only a link bandwidth is considered in the traditional OSPF cost functions. In this paper, we verify the various parameters which can affect link performance, whether it is permissible to use as the parameter of proposed cost functions. To propose new cost functions, we use the effective bandwidth. This bandwidth is calculated by proposed formula using the BER of the network link and link bandwidth. As applied by the proposed triggering condition, the calculated effective bandwidth decrease the unstable of network by generating less link state update messages in wireless networks that frequently changes the link state. Simulation results show that the proposed cost functions significantly outperforms the traditional cost functions in wireless networks in terms of the services of VoIP and data transmission.

A Study on the Application of OSPF for Tactical Environment (전술환경을 고려한 OSPF 적용방안 연구)

  • Lee, Seung-Hwan;Shin, Dong-Wook;Rhee, Seung-Hyong
    • Proceedings of the Korean Information Science Society Conference
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    • 2011.06d
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    • pp.322-324
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    • 2011
  • 전술환경에서는 jamming과 같은 적의 공격과 노드의 잦은 이동에 의해 링크가 불안정 해질 수 있다. 유선환경을 고려한 상용 OSPF는 이러한 문제점에 대하여 적절하게 대응할 수 없는 단점이 있다. 기존의 OSPF는 jamming 신호가 발생하여 링크가 불안정해도 루트가 재설정되지 않는 단점을 가진다. 그리고 노드의 이동에 따른 control 정보의 전송으로 인해 네트워크의 통신 성능이 저하된다. 본 논문에서는 전술환경을 분석하고 기존의 상용 라우팅 프로토콜인 OSPF의 적용 방안에 대해서 알아보고 문제점을 보완할 수 있는 방안을 제안하였다.

A Design and Implementation of a Test Simulator for OSPF Routing Protocol (최단경로 우선 프로토롤(OSPF) 시험 시뮬레이터 설계 및 구현)

  • Lee, Sang-Moon;Jang, Sung-Man;Yoo, Sang-Joo;Lee, Geuk
    • Proceedings of the Korea Information Processing Society Conference
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    • 2003.11b
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    • pp.1081-1084
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    • 2003
  • 국내외 라우터 시장은 급속한 성장추세에 있으며, 이와 같은 추세를 볼때 2004년 국내 라우터 시장은 2조원 정도의 규모가 될것으로 예상되어지고 있다. 하지만 라우터의 핵심 부품이라 칭할수 있는 라우팅 프로토콜은 현재 외국의 와인드리버사나 라우터웨어사에서 상용 라우팅 S/W를 수입하고 있는 실정이며, 고가의 라이센스 비용을 지불하고 있는 실정이다. 본 논문에서 다루고 있는 OSPF의 경우 AREA 간의 라우팅을 위하여 쓰이고 있으며 RFC 2328에 그 스펙이 정의되어져 있다. 여기서는 라우팅 프로토콜을 개발할 경우, 개발한 후에 기능 시험을 해야 하며 이들 기능 시험을 위한 시험 시나리오의 생성, 시험 환경의 구축. 적합성 시험 기술 등에 대한 연구 및 개발이 필요하다. 라우팅 프로토콜 시험 환경의 개발은 OSPF 프로토콜을 구현할 경우 프로토콜 기능을 시험할 수 있는 환경을 구축한다. 본 논문의 주요 내용은 라우팅 프로토콜인 OSPF 라우팅 프로토콜에 대한 시험 시나리오 생성 기술 연구, 시험 환경 구축, 시험 시나리오에 따른 프로토콜 적합성 시험, 망 적응 시험 수행이다. 이러한 기능들을 수행하기 위해 OSPF을 위한 시험 환경을 개발하고 단위 기능들에 대한 시험을 수행 한다.

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OSPF Protocol Extension and Active Packet Delivery Scheme for IP Networks with Active Routers (능동 라우터를 가진 IP 네트워크를 위한 OSPF 프로토콜의 확장 및 능동 패킷 전달 방식)

  • 안상현;김경춘;한민호;나중찬
    • Journal of KIISE:Information Networking
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    • v.30 no.1
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    • pp.126-133
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    • 2003
  • The existing active routing Protocols assume that the active network topology is static or pre-configured. However a dynamic mechanism to route an active Packet according to the network condition is required due to the dynamic characteristic of the active network. As active routing protocols, SLRP and TCOM500 PLAN project have been proposed, but since both of them are based on the assumption of the static topology we can not say that they are dynamic routing protocols in their entirety. Therefore, in this paper, we propose a new active network routing protocol, called AOSPF (Active Open Shortest Path First), which is compatible with the existing IP routing protocol. AOSPF is an extension of OSPF by adding a new LSA (Link State Advertisement) to allow the active network routing. The newly introduced LSA is used to specify whether the corresponding router is an active router or not. and one bit in the OPTION field of an LSA packet is used as the active router indication bit. This way of extending OSPF is similar to the scheme used in the extension of OSPF for multicast, i.e., MOSPF. In this paper, we will present the operation of AOSPF and the way how an active packet is forwarded based on the active network topology information constructed by AOSPF.

The Develonment of an OSPF Protocol Error Detector (OSPF프로토콜 오류 검출기 개발)

  • Hong Changpyo;Kim Tae-Hyong;Lee Hyun-Sung;Cha Won-Soo;Jung Se-Hoon
    • Proceedings of the Korean Information Science Society Conference
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    • 2005.11a
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    • pp.484-486
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    • 2005
  • 수동 시험은 기존의 프로토콜 검증 방법과는 달리 제품이 실제 운용되는 환경에서 입출력의 관찰만을 가지고 제품의 오류를 검출하는 시험이다. 본 논문은 EFSM(Extended Finite State Machine) 모델을 이용하여 homing 기법을 사용하는 수동시험 기법을 제안하고 이를 검증하기 위하여 제안된 수동 시험 기법을 사용하는 OSPF 프로토콜의 오류 검출기를 개발하였다. 개발된 오류 검출기는 Zebra[6]와 시스코 라우터로 구성된 소규모 네트워크에서 Zebra를 이용해 발생시킨 오류 OSPF 패킷을 잘 검출해내었다.

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OSPF Routing Optimization using the Complementary MLS for QoS Provisioning (QoS 보장을 위해 상보형 MPLS를 이용한 OSPF 라우팅 최적화 적용)

  • Lee Gyung-Soo;Jang Seog-Gi;Park Kwang-Chae
    • Proceedings of the IEEK Conference
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    • 2004.06a
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    • pp.237-240
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    • 2004
  • 본 논문에서는 앞으로 광대역통합망에서 사용자의 요구사항에 따른 QoS를 제공하기 위한 연구의 일환으로 여러 가지 서비스 모델과 메커니즘을 살펴보고, 라우팅 최적화를 위한 유전 알고리즘과 hybrid 유전알고리즘에 대하여 논한다. OSPF에 바탕을 둔 라우팅 최적화만으로 QoS가 충분하지 않은 경우 약간의 MPLS 경로가 QoS를 개선하기 위해 설정될 수 있다. 이러한 상보형 MPLS 라우팅을 위한 두 개의 MTP 모델을 제안하고. 적절한 네트워크 QoS 대책으로 네트워크 내의 최대 링크 이용을 고찰한다.

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