2D and 3D digital multimedia files offer numerous benefits like excellent quality, compression, editing, reliable copying, etc. These qualities of the multimedia files, on the other hand, are the cause of fear including the fear of getting access to data during communication. Steganography plays an important role in providing security to the data in communication. Changing the type of cover file from digital multimedia files to protocols improve the security of the communication system. Protocols are an integral part of the communication system and these protocols can also be used to hide secret data resulting in low chances of detection. This paper is intended to help improve existing network steganography techniques by enhancing bandwidth and decreasing detection rates through reviewing previous related work. Recent papers of the last 21 years on network steganography techniques have been studied, analyzed, and summarized. This review can help researchers to understand the existing trends in network steganography techniques to pursue further work in this area for algorithms’ improvement. The paper is divided according to the layers of the OSI model.
Computer networks are based on technology that provides the technical infrastructure where routing protocols are used to transmit packets over the Internet. Routing protocols define how routers communicate with each other by distributing information. They are used to describe how routers communicate with each other, learn available routes, build routing tables, make routing decisions, and share information between neighbors. The main purpose of routing protocols is to determine the best route from source to destination. A particular case of a routing protocol operating within an autonomous system is called an internal routing protocol (IGP – Interior Gateway Protocol). The article analyzes the problem of correctly choosing a routing protocol. Open Shortest Path First (OSPF) and Enhanced Interior Gateway Routing Protocol (EIGRP) are considered leading routing protocols for real-time applications. For this they are chosen to be studied. The main objective of the study is to compare the proposed routing protocols and to evaluate them based on different performance indicators. This assessment is carried out theoretically – by analyzing their characteristics and action, and practically – through simulation experiments. After the study of the literature, the simulation scenarios and quantitative indicators by which the performance of the protocols is compared are defined. First, a network model with OSPF is designed and simulated using the OPNET Modeler simulator. Second, EIGRP is implemented in the same network scenario and a new simulation is done. The implementation of the scenarios shall collect the necessary results and analyze the operation of the two protocols. The data shall be derived and an assessment and conclusion shall be made against the defined quantitative indicators.
The paper proposes a solution to the problem of selecting the bandwidth capabilities of digital communication channels of a transport communication network taking into account the imbalance of data traffic by priorities. The algorithm for selecting bandwidth guarantees the minimum costs associated with renting digital communication channels with optimal bandwidth, provided that the requirements for quality of service of protocol data blocks of the first, second, and k-th priority in an unbalanced in terms of priorities transport communication network are met. At the first stage of solving the problem, using the method of Lagrange multipliers, an algorithm for selecting the capacities of digital communication channels for a balanced in terms of priorities transport network was developed. High performance of this algorithm was ensured by applying algebraic operations on matrices (addition, multiplication, etc.). At the second stage of solving the problem, using the generalized Lagrange multipliers method, we compared the conditional extrema of the cost function for renting digital communication channels for single active quality of service requirements for protocol data blocks, for all possible pairs of active quality of service requirements for protocol data blocks, for all possible triples of active requirements for the quality of service of protocol data units, and so on up to the case when all the requirements for quality of service maintenance of protocol data units are active simultaniously. At the third stage of solving the problem, an example of selecting the bandwidth capabilities of digital communication channels of the unbalanced by priorities transport network consisting of eight routers serving protocol data blocks of three priorities was considered. At the fourth stage of the solution of the problem of the choice of carrying capacities the estimation of efficiency of the developed algorithm by a method of simulation modeling was carried out. To this end, in the environment of the network simulator OMNet ++, the unbalanced in terms of priority transport communication network consisting of eight routers connected by twelve digital communication channels with optimal bandwidth was investigated.
A more detailed representation of Shannon's formula for determining the channel capacity is developed. In a modified form it takes into account the parameters of the signal in both time and frequency range. One of the components introduced to the modified ratio of the Shannon communication channel throughput is the uncertainty relation. A new method of calculating the uncertainty relation for the signals is proposed and described. Examples of calculations of the uncertainty relation for different classes of signals using existing methods and the proposed approach are presented.
In the paper the original algorithm of solution of an applied task of the graph theory on finding of k maximum flows between the two set count's tops is proposed. The approach described represents a complex application of Ford-Fulkerson (Edmonds-Karp or Dinitz) algorithm and the algorithm of creation of a truncated tree of states in width in an indivisible optimizing cycle.
The analytic method for calculation of moments of a sojourn time distribution has been proposed. The comparison with estimations from simulation model and numerical calculations has been considered.
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