To further understand xPON ONU, we need to know xPON. PON (passive optical network) is designed to provide access to multiple end users through only one fiber. EPON and GPON are the two central technology of PON technology, while xPON is an innovative optical fiber access technology system.
What is xPON?
We all know that EPON is based on IEEE 802.3ah standard and GPON is based on ITU -TG.984.x standard. xPON is the integration of EPON and GPON that can support both standards. Also, xPON can provide a unified network management platform for various services including ATM, Ethernet, and TDM.
xPON is compatible with both EPON and GPON and automatically identifies whether EPON and GPON access cards are joined or withdrawn. The unified network management platform is one of the advantages of this system, which combines two different PON technologies into one at the network management level.
Introduction of xPON ONU
As one type of PON, xPON is also composed of an OLT (optical line terminal), a user-side ONU (optical network unit), and ODN (optical distribution network). xPON ONU can support EPON IEEE 802.3ah standard and GPON ITU -TG.984.x standard, allowing it to be used in both EPON and GPON networks. In addition, it can also automatically convert EPON to GPON mode or GPON to EPON mode.
How does xPON ONU Work?
To realize the point-to-multipoint connection and centralized management of ONU equipment, both EPON and GPON networks need ONU registration.
In GPON Mode, ONU and OLT need to create a PLOAM, the physical layer OAM before ONU registers with OLT. PLOAM in the upper link data is a message-based operation and management channel between the OLT and the ONU/ONT.
In EPON mode, ONU and OLT have to create MPCP, Multi-Point Control Protocol before ONU register with OLT. MPCP is designed to ensure that the data is received and sent efficiently.
It can inspect the optical signal through a special mechanism to see whether it is in EPON or GPON mode. As is known to all, EPON and GPON have different protocols, and xPON ONU can automatically change different PON systems according to the user network.
xPON ONU Advantages
As xPON ONU can identify whether the network is in EPON or GPON mode, it is able to switch between two different modes. And it is compatible with both EPON and GPON networks.
EPON has developed for many years, but currently, GPON has become more and more popular. So many customers want to replace EPON with GPON. And xPON ONU plays an important role in switching EPON to GPON. With xPON ONU, the EPON network can be easily upgraded to GPON with the change of head-end.
In general, if the EPON network needs to be transformed to GPON, the original EPON equipment including EPON ONU and EPON OLT should be eliminated. xPON ONU avoids this condition because it is compatible with both EPON and GPON. So users can spend less money on PON equipment, which can totally protect the investment.
xPON ONU Types and Specifications
There are various xPON ONU manufacturers on the market such as HUAWEI, CISCO, Digisol, and Zion (Hello-Signal). Zion (Hello-Signal) provides different xPON ONU products including 1GE xPON ONUs, 2GE xPON ONUs, and 4GE xPON ONUs. Some xPON ONUs also support WIFI functions. For example, ONU GPON/EPON BAFXR-1GE+2.4GWIFI+CATV features layer 2 Home Gateway/CPE that supports Multiple WAN.
Different xPON ONU also has different specifications. Take Zion (Hello-Signal) ONU xPON ABBXR-1GE as an example：
xPON ONU has many advantages in compatibility, bandwidth, investment protection, upgrading, and so on. EPON has already been solidified and xPON ONU will become a trend in the near future as it supports the transmission from EPON to GPON.