How to Resolve Incompatibility Between Huawei GPON and XG-PON ONTs When They Share the Same ODN?

PON terminals are greatly faster than xDSL/LAN terminals and are the mainstream choice for home users. With network development, GPON ONT like Huawei HG8245H HG8010H HG8546M cannot meet the needs of some home users, so XG-PON ONT HN8245Q HN8546Q become more and more popular. But when GPON and XG-PON ONTs share the same ODN, there would be incompatibility problem. This article represents you a solution for this problem.

Table 1 describes the Tx and Rx wavelengths of GPON an XG-PON ONTs.

Table 1 Tx and Rx wavelengths
Type	Downstream Direction	Upstream Direction
GPON	Center wavelength: 1490 mm Wavelength range: 1480-1500   mm	Center wavelength: 1310 mm Wavelength range: 1290-1330   mm
XG-PON	Center wavelength: 1577 mm Wavelength range: 1575-1580   mm	Center wavelength: 1270 mm Wavelength range: 1260-1280   mm

From wavelengths of XG-PON (asymmetric system with upstream rate 2.5 Gbit/s and downstream rate 10 Gbit/s) and GPON ONTs, if they share the same ODN, GPON ONTs (Table 2 lists compatibility) in the earlier stage require wavelength block filter (WBF) for downstream isolation because they are in poor performance in downstream optical signal isolation from XG-PON ONTs. Otherwise, packet loss or even disconnection may occur caused by signal interference. Therefore, the WBF needs to be added on the ONT or optical splitter.

Solution

The WBF is added on the optical splitter for GPON ONTs that are incompatible with XG-PON ONTs sharing the same ODN. Specifically,

·     Male and female connectors.

·     Can be externally connected to the SC/UPC (Shown in the following figure) or AC/APC connector.

Figure 1 SC/UPC connector

Figure 2 and Figure 3 show specific solutions for live networks.

Figure 2 ONTs of different types are connected to the same optical splitter

Figure 3 Only early-stage GPON ONTs are connected to the same optical splitter

Table 2 lists compatibility between GPON ONTs and XG-PON ONTs.

NOTE:

• The time in Compatibility is calculated from the ONT replacement. Detailed markets and BOM codes needed to be queried.
• For details, collect the ONT SN and provide it to the Huawei technical support engineer for querying.

Table 2 Compatibility between GPON    ONTs and XG-PON ONTs
Model	Compatibility
HG810/HG810a/HG850	Supported from the delivery   in June 2012.
HG865/HG866	Supported from the delivery   in January 2011.
HG851/OT550	Not supported.
HG813/HG850a/HG851a	Supported from the delivery   in June 2011.
HG860/HG861	Supported from the delivery   in January 2011.
HG863	Replaced from June 2010.
HG8240/HG8240B/HG8240R/HG8240S/HG8240T/HG8240w/HG8245 /HG8245T/HG8010/HG8110/HG8247/HG8247a/HG8447 /HG8120/HG8120R/HG8242/HG8242B/HG8040/HG8247T/HG8045 /HG8244T	Replaced from June 2010.
HG8010a/HG8010H/HG8010u/HG8245A/HG8245H/HG8110H/HG8240A /HG8240H/HG8240S/HG8240T/HG8240u/HG8045A/HG8012H/HG8247H /HG8242H/HG8040H/HG8045H/HG8045D/HG8245D/HG8245v	Supported by all models.

User-side rate of a Huawei 10G PON ONT can reach up to 1000 Mbit/s, meeting requirements of home users on bandwidth-hungry services such as 4K/8K HD video, AR/VR, home cloud, and video calls. It can also provide private line access services of up to 10 Gbit/s. But at present, GPON ONT has not been totally replaced; GPON ONT and XG-PON ONT are both chosen and can share a same ODN after incompatibility problem solved according to above solution.