Values Of Blocking Probability Research Articles

Hybrid Optimized Approaches for Routing and Resource Reservation Protocols in Optical Networks

We have proposed hybrid approaches to solve dynamic provisioning problems in fixed-grid and elastic optical networks (EON). The proposed approaches use the information from the optimization models, which normally are used to solve static problems, to guide the search for a good solution in dynamic networking. We have presented three models, i.e., Route-Model, RouteRes-Model, and RouteEON-Model. Route-Model computes routing information which is integrated with the first-fit algorithm. RouteRes-Model computes routes and a set of wavelengths for each end pair. Both models are utilized for dynamic provisioning of routing and wavelength assignment in fixed-grid networks. Similarly, RouteEON-Model considers the elastic characteristics of flexible networks and computes routing information. This is integrated with the first-fit algorithm for dynamic provisioning. The proposed solutions efficiently reduce the blocking probability (BP) in fixed-grid networks and the bandwidth BP in EON compared to the shortest path first (SPF) routing and alternate (k=2) routing. Similarly, RouteRes-Model achieved high wavelength utilization compared to other solutions. Finally, the proposed solutions utilized approximately equal number of paths compared to SPF routing. However, compared to SPF routing, Route-Model and RouteRes-Model supported approximately 43% and 66% more traffic respectively while alternate routing supported 36% more traffic for the same values of BPs.

The Effect of Queuing System Capacity on the Blocking Probability Value Using M/G/1/C and G/G/m/K Model in Cloud Data Center

The Effect of Queuing System Capacity on the Blocking Probability Value Using M/G/1/C and G/G/m/K Model in Cloud Data Center

Channelized Blocking Probability Estimation Model for Infrastructure Based Mobile Cognitive Radio

Infrastructure based Cognitive Radio (CR) relies upon a fixed Base Station (BS) where the Secondary User (SU) may be directly connected or through relay chain. For operation in licensed band, either SUs or BS has to remain aware of the current occupancy status of primary channels. In existing literatures, usage histories of the channels are also used by researchers for prediction of future occupancy. Hence, CR operator software has to estimate the blocking probability when an SU places service request. Blocking probability can be estimated by last clock hour (e.g. from 10 am to 11am) occupancy, as in classical teletraffic theory and this estimation has been further improved through prediction models. Both the methods depend on hourly occupancy statistics. Researchers of present paper counts an hour as composed of immediately preceding 60 minutes (e.g. from 10:09 am to 11:08 am if SU place service request at 11:08 am instant). In the present work, minute wise collected occupancy data was calculated for 7 days for 50 cells with different channel capacities. Channelized blocking probability has been calculated based on immediate past 60 minutes occupancy. Instantaneous blocking probability has also been calculated based on current minute occupancy for all available channels as reference. A comprehensive prediction model is employed in the proposed work to compute the instantaneous blocking probability both on immediate minute occupancy basis and its preceding 60 minutes basis from time of request by SU. Validation through actual data establishes that Channelized Blocking Probability estimation model has lower error value compared to estimation through prediction models of other researchers. It was also observed that hourly basis prediction model has constant blocking probability value during clock hour, whereas, minute wise Grade of Service (GoS) prediction model addresses the local peak demand and hence leads to a stringent GoS estimation.

Hybrid Survivability Schemes Achieving High Connection Availability With a Reduced Amount of Backup Resources [Invited

Maximizing connection availability in wavelength division multiplexing (WDM) networks is critical because even small disruptions can cause huge data losses. However, there is a trade-off between the level of network survivability and the cost related to the backup resources to be provided. One-hundred percent survivability can be achieved by dedicated path protection (DPP) with multiple prereserved protection paths for each provisioned connection, i.e., DPP (1:N). Unfortunately, the blocking probability performance of DPP (1:N) is negatively affected by the large number of prereserved backup wavelengths standing by unutilized. On the other hand, path restoration (PR)-based solutions ensure good blocking performance at the expense of lower connection availability. The work in this paper aims at finding hybrid network survivability strategies that combine the benefits of both techniques (i.e., high availability with low blocking rate). More specifically, the paper focuses on a double link failure scenario and proposes two strategies. The first one couples DPP (1:1) with path restoration (referred to as DPP + PR) to minimize the number of dropped connections. The second scheme adds the concept of backup reprovisioning (BR), referred to as DPP + BR + PR, in order to further increase the connection availability achieved by DPP + PR. Integer linear programming models for the implementation of the proposed schemes are formulated. Extensive performance evaluation conducted in a path-computation-element-based WDM network scenario shows that DPP + BR + PR and DPP + PR can significantly lower the blocking probability value compared to DPP (1:2) without compromising too much in terms of connection availability.

Performance Analysis and Estimation of Call Admission Control Parameters in Wireless Integrated Voice and Data Networks

We propose an admission control policy for wireless multimedia networks that is based on the well known threshold-based guard channel method. The new scheme deals with two different types of traffic classes; namely: voice and data. We assume two different thresholds, one for each traffic class. In addition. we propose to buffer the handoff data calls if no free channels are available rather than rejecting them. For handoff voice calls, we propose two methods. namely: a blocking method and a preemptive method. For the blockins method, we reject the handoff voice calls it no channels are available. For the precmptive method, an ongoing data call can be buffered and its channel allocated to the handoff voice call. We study the effect of the thresholds. buffer size and the application of the proposed methods on call blocking probabilities. It is shown that the new call blocking probabilities are only affected by the threshold values. Meanwhile, the data handoff blocking probability exhibited grcat improvement. For handoff voice calls, when the blocking method is applied. the blocking probability value increases slightly with the increase of buffer size. Meanwhile. for the preemptive method, the handoff voice call blocking probability significantly decreases as the buffer size increases. Based on these results. we develop an algorithm that uses the proposed policy to estimate the appropriate thresholds and buffer six which meet the required call blocking probabilities for each traffic type.