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Least Cost Routing pro vytáčené připojení k Internetu
Sameš, Ondřej ; Děcký, Martin (referee) ; Peterka, Jiří (advisor)
The submitted thesis deals in the analysis of the problem of searching the most convenient calls routing in internet telephony. First, there is the telephony environment described regarding current used technologies and market situation, which determines initilal assignment conditions: for each outgoing call we can use services of various providers, whose advantage depends on service quality, charging and call length. The work contains analyses and a solution to this assignment and introduces possible ways to deal with variating call lengths. Further focus is given on the problem of grouping destination addresses into different voice services provider's rates. Second, this work deals in the particular implementation of the assignment solving program and results in a module returning the most convenient connection and a description of its integration in software PBXswitchboard Asterisk, which had been chosen for its universality, openness and expansion and has so enhanced the solution usability. The final module is independent of Asterisk and could be implemented, for instance, into a web interface or used as a stand-alone application. In the conclusion, there is introduced a comparasion with similar solutions as well as a possibility of further expansion and development.
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Security in wireless networks
Mlčochová, Ivana ; Peterka, Jiří (referee) ; Janeček, Jan (advisor)
The more the popularity of wireless networks grows the more threatsb appear of being attacked or misused, either intentionally or by accident. This bachelor work describes security protocols in use, such as WEP, WPA and WPA2, analyses their vulnerabilities and discusses the danger of possible attacks against them. As the security protocol itself cannot entirely protect any wireless network there are additional security measures suggested that minimize the risk of an successful attack. One of the goals was to prove experimentaly that WEP is really as bad a protocol as it is said and should not be used for securing any networks not even the home ones. In connection with that a survey has been made examining how wireless networks in Prague are secured, what protocols are used. This survey showed an alarming fact that most wireless networks are still using deprecated protocol WEP or no security protocol at all.
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Mobility support in Internet and Wireless Network
Novotný, Miroslav ; Peterka, Jiří (referee) ; Janeček, Jan (advisor)
Important part of communication systems is their capability to support mobility of user's devices, eventually of program and data components. This thesis deals with methods of mobility solution in the Internet and Wireless networks. In the chapter relating to the Internet it describes of mobile extensions of IP protocol and methods which use domain names. It summarizes positives and negatives both approaches and suggests a new approach based on distributed hash tables. A part of thesis is also a simulation model of the suggested approach. In the part about Wireless networks it summarizes existing wireless technologies and compares their access to mobility. In the conclusion it states a concept of a full mobile node that uses maximum from the methods discussed above and illustrates the possibilities that the mobility offers.
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Universal Framework for Mngmt and Monitoring of Linux Traffic Control Facilities
Poduška, Jan ; Bulej, Lubomír (advisor) ; Peterka, Jiří (referee)
The terms "Traffic Control" and "Quality of Service" are used in the terminology of packet-switching based computer networks. They refer to control mechanisms, which can assign different priorities to different data flows or guarantee certain properties according to the requirements of an application (e.g. bandwidth, latency, accessibility). The properties guaranteed by the Quality of Service are especially important if the line capacity is limited, especially for applications that need to transmit data in real-time (IP telephony), since these types of applications usually require stable dataflow and are sensitive to delays. This thesis analyzes the current situation in Traffic Control configuration in Linux. The Linux kernel offers a variety of functions for the classification and scheduling of network traffic. However the configuration of traffic control is proving challenging, since the basic concept used is difficult to understand and the configuration language - "tc"- is very difficult to use. Based on the analysis of the current situation, a universal and extensible framework - the jpQOS - was designed and implemented. This allows easy to use and well arranged configuration and monitoring of the QoS using a unified graphical user interface.
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Simulation of network structures
Novák, Pavel ; Kalibera, Tomáš (referee) ; Peterka, Jiří (advisor)
The simulation of network structures can be an effective method for example in teaching, research, or testing the network software, in order to lower the cost of building the real network structure that would be otherwise needed. Moreover, the simulated network can provide some advantages, e.g. simplified control and monitoring, statistical data collecting or visualization of the network behavior. This work focuses on the usage for teaching and testing; illustrates that existing network simulators are not always suitable for this purpose, suggests the architecture and design of a new solution, and offers implementation of the proposed simulation tool.
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Routing simulation in wireless networks
Kouba, Jan ; Peterka, Jiří (referee) ; Kučera, Luděk (advisor)
This work deals with creation of system for routing simulation in wireless networks. System allows the user to enter relevant parameters for simulation and analyses the network. System can assign simulation parameters automaticaly based on chosen algorithm. First it counts node output powers and second communication routes. It is easy to add new algorithms. System is focused on user friendliness and good extensionality. The objective was not to implement realistic model of real network, but to create system where could be new algorithms tested. There is described architecture of the system in the work, so one can continue with development.
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HyperCuts pro filtrování Linuxových paketů
Mašíček, Viktor ; Peterka, Jiří (referee) ; Kučera, Luděk (advisor)
Filtering of packets by multidimensional cutting is one of the new approaches to the solution of the packet classiffication problem. It is based on creating a tree that contains the set rules of filtering. In this case a packets matching is considerably faster than linear traversing of all rules. The HyperCuts methods are one of the latest methods that use multidimensional cutting. At first sight the implementation of the HyperCuts method demonstrated its utility. However, the final decision about the usage of the HyperCuts program in practice can be made only on the basis of the results of testing in it is necessary to can be using in a practice it have to be tested in practical operation. In comparison with the PTree program, which is based on the TBF method, the HyperCuts program, was more successful. The comparison was based on resolving the problem rather than on implementation aspect or success with the same data. In case, where we use PTree source code for confrontation, we compare it with source code of HyperCuts from our implementation. We compare time and memory complexity. In the theoretic part there is explain why the "range match" was used. There is definition of term "cut" which is very advantageous for time and memory complexity. One of the goals of the work was HyperCuts method...
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TCP/IP network controller
Tlach, Jiří ; Yaghob, Jakub (advisor) ; Peterka, Jiří (referee)
The aim of this work is design and implementation of software for an embedded system. Its is based on 8-bit RISC AVR processor connected to Ethernet controller that allows network communication. The software will include processor control as well as control of its peripherals and TCP/IP library for Internet communication. The main goal is to minize code size of developed software because both target AVR processors have very limited size of code memory. The first one has capacity of 8 kilobytes, the second one capacity of 16 kilobytes.
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Configuration and routing mechanisms behaviour in ad-hoc
Vlčková, Zuzana ; Peterka, Jiří (referee) ; Janeček, Jan (advisor)
Technologies of local and personal wireless networks allows building ad-hoc networks which don't require prepared infrastructure of optical or metalic wiring. Besides mechanisms of channel sharing and mechanisms of routing, also mechanisms of topology control are very significant, in these networks. The goal of this diploma project is to evaluate behaviour of chosen mechanisms for topology configuration of wireless ad-hoc networks, optimizing suitable criterion - required energy or interference. Real node distribution of nodes in wireless networks doesn't agree with uniformly or Poisson distribution, published solutions are related to. Interesting would be to evaluate methods minimizing interference for more realistic node distribution (groups of nodes) and also in case of using frequency multiplexing.
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Quality of Service Provision in Wireless Networks
Hnilička, Miroslav ; Janeček, Jan (advisor) ; Peterka, Jiří (referee)
This thesis aims at quality of service provisioning mechanisms in wireless packet networks. The main target of the work is multiple hops wireless networks area in which the problem is more general than in access networks. Theoretical part of the thesis analyses the problem and shows detailed insight of possible solutions. Practical part of the thesis focuses on more specific problem. Impacts of using different particular mechanisms on link and network layers are studied here, considering wireless mesh networks based on IEEE 802.11b technology (WiFi). Simulation model MeshQoS is designed on the basis of discrete simulation system OMNeT++. Inside this model, there are implemented two routing protocols - AODV defined by IETF and newly proposed hybrid opportunistic protocol OMR (OpportunisticMesh Routing). Results of experiments with this model helps to get the notion of the level of quality of services achievable in particular mesh networks configurations. They also show the positive effects of using opportunistic routing principle. In most scenarios OMR provide much lower latency, higher delivery probability and higher throughput.
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