Hello everyone!
Today, we continue to learn more about GPON.
GPON Terminal Authentication
The OLT authenticates the validity of an ONU based on the ONU SN or Password and rejects the access of authenticated ONUs.
In the GPON system, only authenticated ONUs can access the PON System. This meets the requirements of flexible and easy-to-maintain management on the live network.
The main authentication modes for the GPON ONU are as follows:
SN authentication (Common authentication mode)
SN+Password authentication
SN authentication is an authentication mode in which the OLT matches only the SN of an ONU.
The SN+Password authentication mode requires matching both the SN and password at the same time.
GPON ONU Go-Online Process
1. After the O1 Initial state and O2 Standby state are complete, enter the O3 Serial number state.
2. In the O3 Serial number state:
a. The OLT sends a serial number (SN) request to the ONU.
b. The ONU responds to the SN request message sent from the OLT.
c. Upon receiving the SN response from the ONU
If the SN of the ONU is not configured on the OLT (SN authentication is not required), the OLT allocates a temporary ONU ID to the ONU and enters the O4 Ranging state.
If the SN of the ONU is configured on the OLT (SN authentication is required), the OLT compares the SN reported by the ONU with the configured SN. After the comparison succeeds, the OLT enters the O4. If the comparison fails, the initial status of O1 is returned.
3. After the ranging operation is complete in the O4 Ranging state, the system enters the O5 Operation state.
4. In the O5 Operation state:
a. If the GPON ONU does not need to perform password authentication, configure a GEM port for carrying the OMCI message on the ONU, and then enable the ONU to go online. In addition, the OLT reports an ONU online alarm to the CLI or NMS.
b. If the GPON ONU need to perform password authentication:
The OLT sends a password request message to the ONU.
The ONU responds to the password request from the OLT and sends the password to the OLT.
The OLT compares the password returned by the ONU with the locally configured password.
If the password returned by the ONU is the same as the password configured on the OLT, configure the GEM port for carrying the OMCI message on the ONU, enable the ONU to go online, and report the ONU online alarm to the CLI or NMS.
If the password returned by the ONU is different from the password configured on the OLT, the OLT reports a password error alarm to the CLI or NMS. Even if the ONU auto-discovery function is enabled on the PON port, the OLT does not report the ONU auto-discovery. The OLT sends the Deactivate_ONU-ID PLOAM message to deregister the ONU.
GPON Terminal Management Model
The GPON System manages the ONU through t中e OMCI management channel between the OLT and the ONU.
ONU PnP and automatic service provisioning;
ONUs are remotely managed in a centralized manner.
OMCI: optical network terminal management and control interface
SNMP: Simple Network Management Protocol
ONU management in the GPON system is implemented through OMCI messages.
OMCI messages are mainly used for service layer management and maintenance, such as device hardware capability discovery, alarm maintenance information, and service capability configuration.
OMCI is a master-slave management protocol. The OLT is the master device, and an ONU is a slave device.
After the ONU completes the registration process, an OMCI channel is established The OLT controls multiple ONUs connected to it through OMCI channels.
The OMCI supports the offline configuration of ONUs. The ONU does not need to save the configurations locally, which facilitates service provisioning.
ONT Management Mode
1. In all-OMCI mode, the Internet access Service, multicast service, and voice Service are issued through OMCI.
EMS: element management system
2. The Internet access service and multicast Service are issued through OMCI, and the voice service downloads the XML configuration file from the NMS through FTP.
(The OLT downloads the XML configuration file of the voice service from the NMS in FTP mode and delivers the file to the ONT through the OMCI channel to complete the voice service configuration.)
3. The Internet access Service, multicast Service, TLS service, and voice Service of the ONU are configured on the EMS9 or through Telnet login.
However the management VLAN and management IP address can be issued through OM5CI. Therefore, these ONTS can be remotely configured and commissioned or do not require onsite commissioning.
4. OMCI is still used for configuration management, status performance management, and fault management at the PON link layer.
IP-based services, such as Internet access and VolP services, are managed by the ACs in TR-069 mode.
VoIP, RG, and PON indicate VoIP service, gateway service (IP service is used as an example), and PON link-layer management, respectively.
The following figure shows the entire process of GPON service provisioning and terminal zero configuration.
Thanks for reading!
