Tr÷íng ¤i håc Khoa håc, ¤i håc Hu2 Trung t¥m CNTT, V«n pháng TW £ng 3 ¤i håc HuŢ óm tắt. Vi»c t½nh to¡n hi»u su §t t¤i nót lãi trong m¤ng OBS èi vîi tr÷íng hñp luçng l÷u l÷ñng ¸n l Poisson ¢ ÷ñc • cªp kh¡ nhi•u. Trong b i b¡o n y, chóng taei thüc hi»n ph¥n t½ch vîi tr÷íng hñp luçng l÷u l÷ñng ¸n khaeng ph£i l Poisson (non-Poisson) m l qu¡ tr¼nh ¸n renewal (ùng vîi l÷u l÷ñng têng qu¡t GI). Vi»c k¸t hñp c£ hai luçng l÷u l÷ñng GI v Poisson công ÷ñc xem x²t vîi mët tr÷íng hñp °c bi»t cõa qu¡ tr¼nh ¸n mîi l qu¡ tr¼nh IPP (Interrupted Poisson Process). Chóng taei sû döng c¡c ph÷ìng ph¡p x §p x¿ ERT v GI º t½nh to¡n x¡c su §t tc ngh³n. K¸t qu£ ph¥n t½ch b ¶n trong mae h¼nh công nh÷ so s¡nh vîi mae h¼nh Poisson tr÷îc cho th §y t½nh óng cõa mae h¼nh ph¥n t½ch.

Quality of service (QoS) differentiation is an integral component of any networking system, particularly, with the current and future great diversity of users' applications and their manifold requirements. In optical burst switching (OBS) networks, there are two approaches for QoS differentiation: one is based on offset time and the other is based on burst length. This paper presents a mechanism of QoS differentiation based on both offset time and burst length, in which the offset times are calculated to achieve a complete isolation of data loss between priority classes and the burst length is adaptively adjusted according to the feedbacked void size. The simulation results show that the mechanism of QoS differentiation based on offset time and adjusted burst length not only increases the successful scheduling rate but also reduces the burst delay.

No abstract

Retransmission in optical burst switching networks is a solution to recover data loss by retransmitting the dropped burst. The ingress node temporarily stores a copy of the complete burst and sends it each time it receives a retransmission request from the core node. Some retransmission schemes have been suggested, but uncontrolled retransmission often increases the network load, consumes more bandwidth, and consequently, increases the probability of contention. Controlled retransmission is therefore essential. This paper proposes a new controlled retransmission scheme for loss recovery, where the available bandwidth of wavelength channels and the burst lifetime are referred to as network conditions to determine whether to transmit a dropped burst. A retrial queue‐based analysis model is also constructed to validate the proposed retransmission scheme. The simulation and analysis results show that the controlled retransmission scheme is more efficient than the previously suggested schemes regarding byte loss probability, successful retransmission rate, and network throughput.

In this article, a retrial queueing model will be considered with persevering customers for wireless cellular networks which can be frequently applied in the Fractional Guard Channel (FGC) policies, including Limited FGC (LFGC), Uniform FGC (UFGC), Limited Average FGC (LAFGC) and Quasi Uniform FGC (QUFGC). In this model, the examination on the retrial phenomena permits the analyses of important effectiveness measures pertained to the standard of services undergone by users with the probability that a fresh call first arrives the system and find all busy channels at the time, the probability that a fresh call arrives the system from the orbit and find all busy channels at the time and the probability that a handover call arrives the system and find all busy channels at the time. Comparison between four types of the FGC policy can befound to evaluate the performance of the system.