Current Issue : October - December Volume : 2015 Issue Number : 4 Articles : 5 Articles
The paper deals with the development of an\nadvanced solution for a SIP communication server. Works\nwere carried out within the scope of Bright Embedded Solution\nfor IP Telephony (BESIP) project. The output of the\nproject should be a modular architecture with additional functionality\nsuch as speech quality monitoring and security of IP\ntelephony.We sought to unify the configuration of individual\ncomponents based on the NETCONF protocol. In order to be\nable to implement the idea into OpenWrt, we had to integrate\na complex support for the NETCONF configuration protocol.\nOur modifications of OpenWrt in respect of NETCONF\nwere accepted by the OpenWrt community and have been\nincluded in OpenWrt/Trunk branch. The paper explains and\ndescribes the whole concept of the BESIP project and its\nindividual modules....
The Flow-Aware Resilient Ring (FARR)as a new\nproposal for Metropolitan Area Networks is presented and\nanalyzed in this paper. This new solution combines the best\nfeatures of two known network architectures: Flow-Aware\nNetworking and Resilient Packet Ring. Traffic in FARR networks\nis served as flows and implicitly classified into one of\ntwo classes: streaming (with high priority) or elastic (without\npriority but with assured bandwidth). This allows for providing\nQuality of Service guarantees in accordance with network\nneutrality rules. Moreover, high priority traffic is protected in\ncase of a network element failure by the steering mechanism,\nwhich ensures fast traffic redirection in time less than 50 ms.\nThe advantages and weaknesses of the proposed architecture\nare presented along with an analysis of traffic distribution\nin different topologies. The formulae provided in the paper\nallow a decision to be made on whether it is profitable to\nreconfigure a single-ring into a multi-ring topology. Moreover,\nit is shown that simultaneous implementation of FARR\nnetworks with congestion control mechanisms ensures fast,\nscalable and reliable transmission of streaming flows....
The typical approach to steganography is to compress\nthe covert data in order to limit its size, which is reasonable\nin the context of a limited steganographic bandwidth.\nTran coding steganography (Tran Steg) is a new IP telephony\nsteganographic method that was recently proposed that offers\nhigh steganographic bandwidth while retaining good voice\nquality. In Tran Steg, compression of the overt data is used\nto make space for the steganogram. In this paper we focus\non analyzing the influence of the selection of speech codecs\non hidden transmission performance, that is, which codecs\nwould be the most advantageous ones for Tran Steg. Therefore,\nby considering the codecs which are currently most\npopular for IP telephony we aim to find out which codecs\nshould be chosen for transcoding to minimize the negative\ninfluence on voice quality while maximizing the obtained\nsteganographic bandwidth....
We study the bandwidth and multiplexing capacity of an erbium-doped optical memory for quantum\nstorage purposes.We concentrate on the protocol revival of a silenced echo because it has the largest\npotential multiplexing capacity. Our analysis is applicable to other protocols that involve strong optical\nexcitation.We show that the memory performance is limited by instantaneous spectral diffusion\nand we describe how this effect can be minimized to achieve optimal performance....
Multi-carrier code division multiple access (MCCDMA)\ntechnique is a combination of two radio access\ntechniques: CDMA and orthogonal frequency division multiplexing\nand has the advantages of both techniques. The\npaper presents the design of transmitter and receiver for\nMC-CDMA radio interface. It also presents encoders and\ndecoders of turbo codes which were used in simulation of the\nMC-CDMA technique. Two turbo codes with 8-state recursive\nsystematic convolutional were used in the simulation.\nThe simulation results of the transmission quality in additive\nwhite Gaussian noise (AWGN) channel presented in the\npaper show bit error rate and frame error rate performance\nof MC-CDMA technique with the turbo codes and allow for\ncomparison the performance of both turbo codes....
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