Do you know Huawei OTN Line Protection?

Introduction

Optical line protection protects line fibers between adjacent stations using the dual fed and selective receiving function of Huawei OLP boards.

The optical line protection is the 1+1 OMS trail protection that is defined in ITU-T G.872 and ITU-T G.798. The product also supports the 1+1 OTS trail protection.

Table 1 1+1 OTS trail protection, 1+1 OMS trail protection, and 1+1 Multi-OTS trail protection

Protection scheme	Bidirectional switching or unidirectional switching	APS protocol	Application example
1+1 OTS trail protection	Unidirectional switching	Not Support	Figure 1
	Bidirectional switching	Support	Figure 2
1+1 OMS Trail Protection and 1+1 Multi-OTS Trail Protection	Unidirectional switching	Not Support	Figure 3
	Bidirectional switching	Support

Optical Line Protection (1+1 OTS Trail Protection)

As shown in Figure 1 and Figure 2, diverse routes are used to protect a signal against a line fiber fault.

• Figure 1 shows an example of unidirectional switching.
• Figure 2 shows an example of bidirectional switching. In the figure, site B is an OLA site, and there are two OTS sections. Hence, two independent optical line protection groups must be configured. If there is no OLA site between sites A and C, only one optical line protection group is required.

Figure 1 Optical line protection (1+1 OTS trail protection, unidirectional switching) 

 NOTE:

This protection scheme cannot apply to a scenario where the protected service traverses an OLA site. If it is configured for such a scenario, DCN communication between sites may fail.

If SFIU boards are used in the example shown in Figure 1, the TN12OLP04/TN12OLP07 boards must be used to configure the optical line protection.

Figure 2 Optical line protection (1+1 OTS trail protection, bidirectional switching) Huawei SFIU boards do not apply to the scenario shown in Figure 2.

Optical Line Protection (1+1 OMS Trail Protection and 1+1 Multi-OTS Trail Protection)

As shown in Figure 3, when an optical amplifier, FIU board, or fiber fault is present, the system uses diverse routing to protect the signal.

When an OLA site is located between sites A and D, this scenario is defined as a 1+1 multi-OTS protection scenario. When an OTM, FOADM or ROADM site is located between sites A and D, this scenario is defined as a 1+1 OMS protection scenario.

Figure 3 Optical line protection (1+1 OMS Trail Protection and 1+1 Multi-OTS Trail Protection) 

Only TN12OLP03/TN12OLP06/TN13OLP03 can be used in this scenario.

Optical line protection (1+1 OMS Trail Protection and 1+1 Multi-OTS Trail Protection) configurations are the same in unidirectional and bidirectional switching applications.