Enhancing Bandwidth Utilization of IP Telephony Over IPv6 Networks

The demand for the telecommunication services,such as IP telephony,has increased dramatically during the COVID-19 pandemic lockdown.IP tele-phony should be enhanced to provide the expected quality.One of the issues that should be investigated in IP telephony is bandwidth utilization.IP telephony pro-duces very small speech samples attached to a large packet header.The header of the IP telephony consumes a considerable share of the bandwidth allotted to the IP telephony.This wastes the network's bandwidth and influences the IP telephony quality.This paper proposes a mechanism(called Smallerize)that reduces the bandwidth consumed by both the speech sample and the header.This is achieved by assembling numerous IP telephony packets in one header and use the header'sfields to carry the speech sample.Several metrics have been used to measure the achievement Smallerize mechanism.The number of calls has been increased by 245.1%compared to the typical mechanism.The bandwidth saving has also reached 68%with the G.28 codec.Therefore,Smallerize is a possible mechanism to enhance bandwidth utilization of the IP telephony.

QoS Guaranteed and Adaptive Downstream Bandwidth Utilization Scheme for Ethernet Passive Optical Networks

Dynamic bandwidth allocation（DBA） is an open and hot topic in the Ethernet passive optical network（EPON） ,which is regarded as one of the best choices for next-generation access networks. However,most proposed DBA schemes ignore the quality of service（QoS） guarantee on maximum delay and delay jitter for the real-time traffic and the downstream bandwidth utilization under light upstream load in EPON. In this paper,a new DBA scheme,QoS guaranteed adaptive downstream bandwidth utilization（QoS-ADBU）,is proposed. This scheme can provide better QoS assurance by determining the maximum transmission cycle time according to the maximum acceptable packet delay and delay jitter for real-time traffic. Besides,the downstream utilization can also be improved by adapting the polling frequency to downstream traffic load.

Dynamic bandwidth allocation algorithm for full-band utilization

To improve and optimize the bandwidth utilization for multi-service packet transporting system, a kind of Dynamic Full Bandwidth Utilized （DFBU） allocation algorithm allowing a single link to use far beyond its fair share bandwidth is presented. Three important parameters as the bound on max and minimum bandwidth, the maximum packet delay and the minimum bandwidth utilization are discussed and analyzed. Results of experiments show that the DFBU-algorithm is capable of making a single link in the system use all the spare bandwidth （up to full-bandwidth） while the performance of fairness and QoS requirement is still guaranteed.

Tricube Weighted Linear Regression and Interquartile for Cloud Infrastructural Resource Optimization

Cloud infrastructural resource optimization is the process of precisely selecting the allocating the correct resources either to a workload or application.When workload execution,accuracy,and cost are accurately stabilized in opposition to the best possible framework in real-time,efficiency is attained.In addition,every workload or application required for the framework is characteristic and these essentials change over time.But,the existing method was failed to ensure the high Quality of Service(QoS).In order to address this issue,a Tricube Weighted Linear Regression-based Inter Quartile(TWLR-IQ)for Cloud Infrastructural Resource Optimization is introduced.A Tricube Weighted Linear Regression is presented in the proposed method to estimate the resources(i.e.,CPU,RAM,and network bandwidth utilization)based on the usage history in each cloud server.Then,Inter Quartile Range is applied to efficiently predict the overload hosts for ensuring a smooth migration.Experimental results show that our proposed method is better than the approach in Cloudsim under various performance metrics.The results clearly showed that the proposed method can reduce the energy consumption and provide a high level of commitment with ensuring the minimum number of Virtual Machine(VM)Migrations as compared to the state-of-the-art methods.

Survey and Analysis of VoIP Frame Aggregation Methods over A-MSDU IEEE 802.11n Wireless Networks

The IEEE 802.11n standard has provided prominent features that greatly contribute to ubiquitous wireless networks.Over the last ten years,voice over IP(VoIP)has become widespread around the globe owing to its low-cost or even free call rate.The combination of these technologies(VoIP and wireless)has become desirable and inevitable for organizations.However,VoIP faces a bandwidth utilization issue when working with 802.11 wireless networks.The bandwidth utilization is inefficient on the grounds that(i)80 bytes of 802.11/RTP/UDP/IP header is appended to 10–730 bytes of VoIP payload and(ii)765μs waiting intervals follow each 802.11 VoIP frame.Without considering the quality requirements of a VoIP call,be including frame aggregation in the IEEE 802.11n standard has been suggested as a solution for the bandwidth utilization issue.Consequently,several aggregation methods have been proposed to handle the quality requirements of VoIP calls when carried over an IEEE 802.11n wireless network.In this survey,we analyze the existing aggregation methods of VoIP over the A-MSDU IEEE 802.11n wireless standard.The survey provides researchers with a detailed analysis of the bandwidth utilization issue concerning the A-MSDU 802.11n standard,discussion of the main approaches of frame aggregation methods and existing aggregation methods,elaboration of the impact of frame aggregation methods on network performance and VoIP call quality,and suggestion of new areas to be investigated in conjunction with frame aggregation.The survey contributes by offering guidelines to design an appropriate,reliable,and robust aggregation method of VoIP over 802.11n standard.

Down to Zero Size of VoIP Packet Payload

Voice over Internet Protocol(VoIP)is widely used by companies,schools,universities,and other institutions.However,VoIP faces many issues that slow down its propagation.An important issue is poor utilization of the VoIP service network bandwidth,which results from the large header of the VoIP packet.The objective of this study is to handle this poor utilization of the network bandwidth.Therefore,this study proposes a novel method to address this large header overhead problem.The proposed method is called zero size payload(ZSP),which aims to reemploy and use the header information(fields)of the VoIP packet that is dispensable to the VoIP service,particularly the unicast IP voice calls.In general,these fields are used to carry the VoIP packet payload.Therefore,the size of the payload is reduced to save bandwidth.The performance estimation results of the proposed ZSP method showed a considerable improvement in the bandwidth utilization of the VoIP service.For example,the saved bandwidth in the tested scenario with the G.723.1,G.729,and LPC codecs reached 32%,28%,and 26%respectively.

Graded index separate confinement heterostructure transistor laser:analysis of various confinement structures

A new configuration of the confinement structure is utilized to improve optoelectronic performance, including threshold current, ac current gain, optical bandwidth, and optical output power of a single quantum well transistor laser. Considering the drift component in addition to the diffusion term in electron current density, a new continuity equation is developed to analyze the proposed structures. Physical parameters, including electron mobility, recombination lifetime, optical confinement factor, electron capture time, and photon lifetime, are calculated for new structures. Based on solving the continuity equation in separate confinement heterostructures, the threshold current reduces 67%, the optical output power increases 37%, and the-3 d B optical bandwidth increases to 21 GHz（compared to 19.5 GHz in the original structure） when the graded index layers of AlξGa1-ξAs（ξ：0.05 → 0 in the left side of quantum well, ξ：0 → 0.02 in the right side of quantum well） are used instead of uniform Ga As in the base region.

Generation of optical frequency comb squeezed light field with TEM_(01) transverse mode

Nonclassical optical frequency combs find tremendous utility in quantum information and high-precision quantum measurement. The characteristics of a type-I synchronously pumped optical parametric oscillator with the TEM_（01） transverse mode below threshold are investigated and a squeezing of 0.7 dB for an optical frequency comb squeezed light field with the TEM_（01） transverse mode is obtained under the pump power of 130 m W. This work has a promising application in three-dimensional space-time measurement.