To realize the point-to-multipoint connection and centralized management of ONU equipment in the PON network, both EPON and GPON networks define the management protocol of ONU. The management protocol of EPON is OAM, and the management protocol of GPON is OMCI.
Because the management protocols of EPON and GPON are different, the ONU devices of EPON and GPON cannot be mixed. Otherwise, the OLT cannot identify the ONU.
ONU registration and essential device management are all done through management protocols (OAM or OMCI). The ONU is successfully registered on the OLT, and the OLT has configured the service channel of the ONU. This is a necessary and first condition for the regular operation of all ONU services.
The usual understanding of the compatibility customers asks about refers to the ONU registration and the OLT’s service configuration. Registration compatibility is generally whether the OLT is compatible with third-party ONUs. The compatibility of the service configuration issued by the OLT mainly depends on whether the structure allocated by the OLT includes the function of the manufacturer’s private OAM/OMCI protocol.
Basic ONU registration process
ONU basic registration authentication method
PON terminal authentication means that ONUs must pass the legality authentication of the OLT before they can successfully register with the OLT.
Only ONUs that have passed legal certification can access the PON system in the PON system, which can satisfy operators to implement flexible and easy-to-maintain management methods.
Main authentication methods of GPON ONU:
- GPON SN certification // Commonly used certification methods for domestic and overseas customers
- Password authentication
- GPON SN+Password authentication
- LOID certification
- LOID+Password authentication // Commonly used authentication methods for domestic operators
- Main authentication methods of EPON ONU:
- MAC authentication // Commonly used authentication methods for domestic and overseas customers
- LOID certification
- LOID+Password authentication // Commonly used authentication methods for domestic operators
Optical port of ONU equipment (ONU PON port)
Currently, ONUs use optical receivers and transmitters, which can be divided into two types according to the package: optical modules and BOSA. Both of them are optical receivers and transmitters used on ONUs,
The function is: as a communication interface, when the ONU sends upload data, it converts the transmitted electrical signal into a 1310 wavelength optical signal and transmits it to the OLT; when the ONU receives download data, it converts the 1490 wavelength optical signal into an electrical signal.
Basic parameters of ONU optical port:
- Optical working wavelength: upstream 1310nm, downstream 1490nm
- Optical emission power value: 0-4dBm (upstream 1310nm wavelength light)
- The lowest light receiving sensitivity: -28dbm (downstream light with a wavelength of 1490nm)
- Overload optical power value: -8dBm (downstream light with a wavelength of 1490nm)
- The longest transmission distance: 20km
- EPON ONU: upload rate 1.25Gbit/s, download rate 1.25Gbit/s
- GPON ONU: upload rate 1.25Gbit/s, download rate 2.5Gbit/s
The average working transmit optical power value of the ONU PON port (BOSA) should be in the range of 0~4dBm, and the received optical power value of the ONU PON port should be in the field of -8dBm to -28dBm.
If the transmitted optical power value of the ONU PON port (BOSA) is too high or too low, it may cause the ONU to fail to register. The same BOSA received optical power value is too high (greater than -8dBm) or too low (less than -28dBm), also Will make ONU unable to register and use usually.
Therefore, during the ONU production process, all ONUs will calibrate the BOSA’s transmit optical power value and the minimum receiving sensitivity value to the above standard values.
