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Methods for the measurement of bit rates in data networks
Franc, Jan ; Martinásek, Zdeněk (referee) ; Zeman, Václav (advisor)
The target of this master's thesis were the known methods for testing the quality of transfer parameters of data networks. I have studied the RFC 2544 document to analyze these tests. From that information and by studying other existing web-based applications I was able to design a concept of my own application that will allow to measure basic quality parameters of transfers made through the Internet (the parameters: downstream, upstream, latency, variance of these and a traced route). My application doesn't require any modifications on the user's system. It's built on the server-based programming language PHP and uses the relational database engine MySQL to store measurement and user data. On the client side, it's assisted by the JavaScript scripting language. Both registered users and visitors are allowed to perform the listed measurements. Registered users are able to browse the history of their own benchmark results and also to send messages to others. There is an administrative account to oversee the operations. Another part of my thesis work is an application for Windows that performs the same measurements but does not use JavaScript.
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Simulation of data transmission latency between nodes in IP networks
Balej, Jiří ; Molnár, Karol (referee) ; Komosný, Dan (advisor)
This master thesis is focused on the delays incurred in data transmitting over IP networks. The top of the paper is devoted to points, where delay is invoked and causes of the latency. For individual sources of delay are are described the parameters that affect the usual size of latency. The next section describes the types of networks and their typical delay. In the paper are also discussed tools for measuring delay and determining the number of intermediate devices. The thesis contains results of measurements delay time in the real network. For these results are listed conclusions about the delay for one intermediate device. There is also said general ratio of crow-fly distance and calculated distance. The last part deals the simulation of delay in the NS2 program. The results of thesis are scripts that shows the relation of delay and the number of switches, routers, and the length of the path.
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Host distance measurement using ICMP protocol in IP networks
Fojtová, Lucie ; Komosný, Dan (referee) ; Burget, Radim (advisor)
Current internet more and more often faces the problem of the right definition of distance between the single hosts. The knowledge of this quantity influences the areas of the optimal lay-out of overlay multicast networks, the right selection of peer-to-peer network participant, or the simple decision of the end user: which one of the nearest mirrors to use for downloading datas. The nearest one doesn't have to mean the nearest in geographical point of view - the distance on Internet is usually expressed by quantities as latency or bandwidth. All these examples have got the saving of bandwidth in common and therefore economical saving. The methods of host position prediction in networks work on the basis of measuring latency parameter. The tools for measuring of this parameter will be set up in this thesis and at the same time it will be shown how geographical distance and latency correspond with each other.
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