• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1158-1163
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• 2002

In this paper it is focused on the relation between CLR (Cell Loss Ratio) and blocking probability, GoS(Grade of Services) parameters in the wireless ATM (Asynchronous Transfer Mode) access network which consists of access node and wireless channel. Traffic model of wireless ATM access network is based on the cell scale, burst scale and call connection level. The CLR equation due to buffer overflow for wireless access node is derived for CBR (Constant Bit Rate) traffic. The CLR equation due to random bit errors and burst errors for wireless channel is derived. Using the CLR equation for both access node and wireless channel, the CLR equation of wireless ATM access network is derived. The relation between access network CLR and blocking probability is analyzed for CBR traffic.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9B
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• pp.596-601
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• 2005

In this paper it is focused on the relation between CLR(Cell Loss Ratio) and blocking probability in the wireless ATM access transport. Traffic model of wireless ATH access transport is based on the cell scale, burst scale and call connection level. The CLR due to buffer overflow for wireless access node is derived for VBR traffic. The CLR due to transmission errors for wireless channel is derived. Using the CLR for both access node and wireless channel: the CLR of wireless ATM access transport is derived. The relation between CLR and blocking probability is analyzed for VBR traffic to evaluate performance of wireless ATM access transport.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.6 no.3
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• pp.1-7
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• 2007

In this paper, we propose a new prioritized Optical Burst Switching (OBS) protocol based on a hop count, which can provide efficient utilization in optical networks. Under several legacy schemes, a switch drops the burst with the shortest time regardless of its traversed hop count. As a result, a dropped burst that have been traversed many hops might cause increased bandwidth waste compared to one that has traversed a few hops. To improve this problem, we propose the Just Enough Time (JET) with a hop counting scheme which can reduce the wasted bandwidth by prioritizing the burst traversed many hops over others. From the simulation result, it is preyed, we show that the proposed scheme has advantages against legacy schemes in terms of the burst blocking probability and the link utilization.

• ETRI Journal
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• v.40 no.5
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• pp.624-633
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• 2018

Fair bandwidth allocation (FBA) has been studied in optical burst switching (OBS) networks, with the main idea being to map the max-min fairness in traditional IP networks to the fair-loss probability in OBS networks. This approach has proven to be fair in terms of the bandwidth allocation for differential connections, but the use of the ErlangB formula to calculate the theoretical loss probability has made this approach applicable only to Poisson flows. Furthermore, it is necessary to have a reasonable fairness measure to evaluate FBA models. This article proposes an approach involving throughput-based-FBA, called TFBA, and recommends a new fairness measure that is based on the ratio of the actual throughput to the allocated bandwidth. An analytical model for the performance of the output link with TFBA is also proposed.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.8 no.4
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• pp.195-200
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• 2009

In this paper, we propose a new priority Optical Burst Switching (OBS) protocol based on a hop count, which can provide an efficient utilization in optical wireless networks. Under several legacy schemes, a switch drops the burst with a shorter time among ones regardless of its traversed hop count. As a result, the dropped burst that have been traversed more hops might cause to waste bandwidth than the one traversed a few hops. Noting that this problem, we propose a Just Enough Time (JET) with a hop count scheme which can reduce the wasted bandwidth by prioritizing the burst traversed more hops over others. The simulation results shows that the proposed scheme has more advantages over the legacy schemes in terms of the burst blocking probability and the link utilization.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.9 no.1
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• pp.7-12
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• 2010

In this paper, we propose a new prioritized Optical Burst Switching (OBS) protocol based on a hop count, which can provide an efficient utilization in optical Wireless networks. Under several legacy schemes, a switch drops the burst with a shorter time among ones regardless of its traversed hop counts. As a result, the dropped burst that have been traversed more hops might cause to waste bandwidth than the one traversed a few hops. Noting that this problem, we propose the Just Enough Time (JET) with a hop count scheme which can reduce the wasted bandwidth by prioritizing the burst traversed more hops over others. From the simulation result, we show that the proposed scheme is advantageous over the legacy schemes in terms of the burst blocking probability and the link utilization.

• ETRI Journal
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• v.29 no.5
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• pp.682-684
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• 2007

A new scheme to alleviate contention in optical burst switching networks is proposed. It consists of preventively reserving resources in a node, to be used if resources are busy on the next hop node. The burst is sent back to the preceding node and then resent forward. Simulations are carried out to assess the feasibility of the proposed scheme. Its performance is compared with that of contention resolution based on deflection routing.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.12
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• pp.31-36
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• 2005

In this paper, we propose a new optical switching system as a infrastructure of the BcN, in which the high traffic volume will be expected due to the multimedia service, like P2P services. Because the JET protocol, the most popular protocol in OBS (Optical Burst Switching) research area, has high blocking probability for burst, it prevents commercialization in real network for its low throughput in TCP layer. To improve high blocking rate in OBS network, we segment large network into small network and perform burst scheduling to avoid burst loss. By using proposed scheme, Internet provider can reduce network deployment cost in Metro network as well as large mesh core networks

• Proceedings of the Korea Society for Simulation Conference
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• 2001.05a
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• pp.132-132
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• 2001

본 논문에서는 혼합예약요청(hybrid reservation request) 알고리즘을 적용한 새로운 동적 예약 TDMA 프로토콜을 제안한다. 제안된 혼합 예약 요청 알고리즘은 기존의 랜덤접속방식과 기지국의 중재 없이 단말간 직접 신호교환을 통하여 이웃 단말의 새로운 예약 요청을 대신 전송하는 방식을 혼합해서 사용하는 방법이다. 이 알고리즘은 기존 slotted-ALOHA 방식을 이용한 예약 요청의 비효율성을 개선하여 새로운 단말의 예약 요청실패로 인한 셀 전송지연 및 호 봉쇄 확률(call blocking probability)을 줄이기 위한 목적으로 제안되었다. 제안한 알고리즘은 새로 전송할 데이터를 가진 단말이 많은 경우에 특히 효율적이다. 본 논문에서 제안하는 프로토콜은 모든 종류의 트래픽이 예약을 통한 전송방식으로 전송된다. 즉, 단말들로부터의 예약 요청을 바탕으로, 기지국이 스케줄링을 하여 트래픽 별로 접근 슬랏을 할당해 주는 방식이다. 이 경우, 예약 요청을 하는 방법은 새로 전송을 개시하는 단말과 이미 전송중인 단말의 경우가 다른데, 새로운 전송을 위한 예약이 필요한 단말은 제안하는 알고리즘을 이용하며, 이미 예약에 성공한 단말은 기존에 사용하던 자신의 버스트헤더(burst header)에 피기백(piggybacking)하는 방법을 이용한다. 제안한 알고리즘에 따라, 새로 접속하는 단말이나 새로운 예약 요청이 필요한 단말은 두 단계로 요청을 전송할 수 있다. 첫 번째 단계는 이미 예약에 성공하여 전송중인 이웃단말에게 전송요청신호를 보내 간접적으로 기지국에게 예약을 요청하는 방법이며, 두 번째 단계는 첫 번째 방법이 실패했을 경우 기존의 랜덤접속방법에 참가하는 것이다 먼저 첫 번째 방법에서는 단말이 랜덤접근 구간의 예약요청구간(resonation request)중 하나의 미니 슬랏을 선택해 이웃 단말들에게 한번 방송(broadcast) 한다 이후 ACK 응답구간(ACK receive)에서 응답을 받으면 예약요청성공이라 간주하고, 그렇지 않으면 실패로 판단, 뒤이어 오는 랜덤접근구간(normal random access period)에 참가하여 기지국에게 직접 예약 요청을 한다. 시뮬레이션은 기존 slotted-ALOHA방식으로 랜덤 접속을 할 경우와 제안한 방식과의 성공률을 비교해 제안한 방식의 call blocking probability가 낮음을 보였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.10
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• pp.8-15
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• 2003

In this paper, we address how to provide absolute differentiated services for optical burst switching (OBS) networks based on dynamic wavelength assignment. Unlike existing quality of service (QoS), such as buffer-based and offset-time based scheme, our proposed dynamicvirtual lambda partitioning (DVLP) scheme does not mandate any buffer or extra offset time, but can achieve absolute service differentiation between classes. This new DVLP scheme shares wavelength resources based on several different priority of classes in an efficient and QoS guaranteed manner. The performance results show that the proposed scheme effectively guarantees a target blocking probability of each traffic classes both in Poisson and Self-similar traffic environment.