**Notes/thanks/other declarations**

*Telecommunication Systems – Principles and Applications of Wireless-Optical Technologies*

According to its grant policy, the European Union should contribute to building high-speed networks in the member states. This chapter introduced the state of the art in the field of Internet access technologies in the Czech Republic. The Czech Republic, as a member of the European Union, has committed to building high-speed Internet access for at least half of the households by 2020. Current market research has shown that WiFi technology is still dominant in the Czech Republic. The Czech Republic is behind the trend in FTTH/FTTB high-speed fiber optic connections by up to 10 and 5% for FTTB

The key part of this chapter is dedicated to the analysis of data transmitted in the GPON network. In cooperation with the Internet service provider Orange Slovakia, an active capture of transmitted data on the network was performed. As soon as the activation process of the end unit was completed successfully, data communication in both directions in GPON networks was possible. On the one hand, the sequence of the associated messages was defined by ITU-T Recommendation G.984, but on the other hand, it was only a recommendation and the specific implementation was fully within the manufacturer's competencies. Even though the end units were supposed to preserve the frame structure and the transmitted messages, as a result of the previously mentioned facts, it was often the case that the different manufacturers' end units were not compatible among themselves. Within the context of our analysis, TraceSpan's GPONxpert tool was used to capture network data. This device allowed for active listening of communication and real-time evaluation of its parameters. Detailed data analysis was a necessary form of postprocessing. To present the result of the activation process analysis, a sequence of key messages ensuring the activation of the end unit was displayed. Using these messages, it was possible to read the manufacturer and serial number of the end unit, set parameters such as ONU-ID and Alloc-ID. The OMCI channel provided end user parameters for a defined set of services, most often by downloading a profile image file corresponding to paid services and speeds. According to the reports, it was obvious that the VoIP param-

Transmission of "Dying Gasp" messages was a special case of the activation process, or the logout and release of allocated parameters of the associated end units. These messages reflected a power outage of these units. Because the end units had unique UNU-ID/Alloc-ID parameters, the same parameters were used for other end units in the event of a power failure occurring in an already activated

The presented research has been supported by a project of the Ministry of the Interior under grant no. VI20172019072, "E-infrastructure CESNETmodernization," registration no. CZ.02.1.01/0.0/0.0/16 013/0001797, and the National Sustainability Program under grant no. LO1401. For the research, the

**6. Conclusion**

and FTTH, respectively.

eters were also set.

**Acknowledgements**

**Conflict of interest**

infrastructure of the SIX Center was used.

The authors declare no conflict of interest.

unit.

**82**

Tomas Horvath would like to dedicate his part to his girlfriend (Lucie Baierova) and his family (Dagmar, Jan, and Petra). They have supported him during his University study. He also would like to give thanks to Ales Buksa for his support at the University. Ales has taught and inspired him with many things in his personal life.
