This paper proposes an innovative application of passive optical networks with optimized bus topology for local backbone data networks. Passive optical networks represent a promising solution for modern access networks to meet the increasing demands on transmission rate for demanding multimedia services. As these networks rely exclusively on passive components implemented in their entire infrastructure, it is necessary to consider their certain specific features and optimize properly necessary parameters, especially an attenuation balance. Considering the possibility of such optimization, the passive optical network with optimized bus topology provides several interesting opportunities for specific applications. Its potential application is, for example, a high-speed local backbone infrastructure connecting local data switches and routers. For that purpose, the passive optical splitter with adjustable power splitting ratio at its outputs can be used for the optimization process of attenuation balance. This paper presents a mathematical apparatus for calculating the maximum number of splits and the number of bridge taps in the passive optical network with the bus topology and an example of obtained results.

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The plan of transmission parameters or the network plan was created for Czech Republic in 2005 and this plan has had key effect on traffic in the telecommunication networks providing public telephone service, including mobile networks, NGN networks based on IP protocol and private networks connected to public telephone network. This paper describes practical effects of aforesaid plan on some typical situations in the network. Related research projects of the Department of Telecommunications Engineering, Faculty of Electrical Engineering, CTU in Prague are presented here, such as tandem arrangement of codecs and non-intrusive monitoring of voice quality.

Today, tree or hybrid tree‐star topologies are mostly used for passive optical networks in practice. However, these topologies are significantly vulnerable against the failures of a central optical line termination (OLT) unit. Recently, an innovative idea about forming a simple ring topology by using asymmetric passive splitters together with secondary OLT unit has been presented and an elementary mathematical model for calculations of optimum splitting ratios of all splitters in a ring infrastructure has been described. The major advantage of presented ring topology is that both primary and secondary OLT units can be placed on the opposite sides of the ring, which could greatly increase the overall resistance of the whole network against critical failures, malfunctions, or sophisticated attacks. Next, this ring topology was successfully realized in practice by using real OLT and optical network units and the whole idea verified. The results of real measurements as well as theoretical calculations are presented in this article. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2201–2205, 2013

Passive Optical Networks (PONs) are mostly used as modern high-speed access networks today. Typically, PONs are based mainly on tree or hybrid tree-star topologies in practice. However, these topologies are significantly vulnerable, especially in case of sophisticated attacks or global malfunctions of central optical line termination (OLT) units. Due to that, an innovative idea of forming PON with a simple ring topology by using standard passive splitters was proposed and is presented within this paper. Thanks to a ring topology, the secondary OLT unit can be placed in any potential location within the ring and this can significantly increase the vulnerability of the whole network. The article contains the description of this idea and also necessary simulations were performed. To verify these theoretical assumptions, experimental PON network with a ring topology was created and its characteristics were measured and compared with simulations and models. Moreover, the functionality of the protection mechanism was confirmed as well as the functionality of the entire ring PON network.