Rate and give feedback:
Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document.
Note: Even the most advanced machine translation cannot match the quality of professional translators.
Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Upstream and Downstream Transmission
On a PON network, downstream refers to data transmission from an OLT to an ONU, and upstream refers to data transmission from an ONU to an OLT. The downstream and upstream transmission processes are:
- Downstream: An OLT broadcasts IP packets of data, voice, and video services to all ONUs through 1:N ODN. After an ONU receives a data frame, it checks the logical identifier of the data frame at the physical layer. If the logical identifier is the same as the local identifier allocated by the OLT, the ONU accepts the data frame; if not, the ONU discards the data frame.
- Upstream: A 1:N ODN uses the time division multiple access (TDMA) function to couple signals of various services from multiple ONUs to one optical fiber and sends the signals to the OLT. Signals of different services do not interfere with each other during transmission.
PON interfaces on the router transmit data to an OLT; therefore, these interfaces are also called upstream PON interfaces.