3 Types of optical networks, their architectures and basic parameters (OTH, FFTx)
3.1 FTTx architecture

FTTx (Fibre to the …cabinet, curb, building, office, home) – access network based on optical fibres. All-optical network FTTO and FTTH or hybrid solutions FTTEx, FTTCab, FTTC, FTTB.

### Hybrid solutions

In general:

- Optical fibres are combined with symmetric metallic lines for ADSL2+ VDSL2.
- Optical fibres are combined with coaxial cables for Cable TV (CATV).
- Combination with wireless network.

- FTTEx (Fibre to the Exchange) – optical fibres are terminated at the local telephone exchange, DSLAM multiplexor splits signal to existing metallic lines to provide xDSL (Digital Subscriber Line). FTTEx is the most common solution nowadays, but it is not an all-optical access network.
- FTTCab (Fibre to the Cabinet) – optical fibres are terminated in an outdoor splitter.
- FTTC (Fibre to the Curb) – optical fibre reaches the group of buildings.
- FTTB (Fibre to the Building) – optical fibres reach particular buildings, they can be terminated inside them at the particular telephone boxes or they may be followed by wireless connection.

### All optical solutions

- FTTO (Fibre to the Office) – optical fibres terminate at the office of important customers with huge demands on the transmission rate.
- FTTH (Fibre to the Home) – optical fibres are terminated at the end user’s socket.