This Technical Report describes the FTTX-network. As a guideline other parts of the fibre optic infrastructure
are given in this clause.
First some basics: sound, pictures, voice, data carried by networks are digital data expressed in terms of bit,
bytes and their multiples (kilo (k), mega (M), giga (G), tera (T)). A bit (binary digit) is the smallest digital unit
and has only two values: 0 or 1. A byte includes 8 bits and defines the size of a data file. Transmission
capacity of networks and terminals is not expressed by using bytes, but using bit per second (bps). When a
data file is transferred in a network two supplementary bits are necessary. It means that 10 bits are required
for 1 byte.
In the case of a VDSL subscriber with 10 Mbit/s, who wants to upload a pdf data file, the Web provider
indicates for instance the following size: 20 Megabytes. It should then take 20 s. However, for any Mbit/s
subscription the fact is that the real final data flow is about a quarter of the notified data flow, because the
data flow is shared between subscribers and its quality depends on the activity of the other subscribers. It
means that the 20 Megabytes data file will need 1 min 20 s to be uploaded. For instance a 15 Mbit/s ADSL
system gives only 1 Mbit/s for uploading. The following table gives some further examples of transmission
times for uploading a quality DVD-movie, if there is no data flow sharing.
We do not know the new tools that will be created by the real high bit rate networks. New applications (not
invented today) will appear and applications originally dedicated to professionals will be extended to all in a
similar way as it happened with the mobile phone.
It is important to define the meaning of « low, medium and high bit rate transmission ». One possible
classification is presently the following:
− low bit rate transmission: up to 1 Mbit/s
− medium bit rate transmission: 1 up to 10 Mbit/s
− high bit rate transmission: 10 up to 100 Mbit/s and more.
BS PD CLC/TR 50510:2007 history
2021BS PD CLC/TR 50510:2021 Fibre optic access to end-user. A guideline to building of FTTX fibre optic network
2012BS PD CLC/TR 50510:2012 Fibre optic access to end-user. A guideline to building of FTTX fibre optic network
2007BS PD CLC/TR 50510:2007 Fibre optic access to end-user — A guideline to building of FTTX fibre optic network