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Huawei OSN3500 SDH transmission equipment SNCP subnet connection protection is mainly used to realize the protection of cross-subnet services with double transmitter and receiver selection. The subnet can be a chain, a ring, or a more complex network. Functional applications require the support of corresponding equipment and single boards.SNCP realizes the function of protection by applying select-and-receive on the host side to the two service sources that are sent to the source side in a double send and receive manner, so double send and receive is a feature of SNCP. SNCP realizes the protection of services by double-sending the services at the source end and selecting and receiving the two services that are double-sent at the host end. With the function of double sending and receiving, it is suitable for the protection of cross-subnet services. When SDH services are configured in the single-site mode, when the cross-subnet services need to be protected, they can be realized by creating SNCP. The biggest feature of the service is that it adopts a dedicated physical channel as the protection channel and the service is dual transmitter-receiver selective. When configuring SNCP services, you need to configure the working service and the protection service separately. The network is configured with SNCP to be able to protect the SNCP service on the working path.
Fault Description
Huawei's SDH transmission equipment misplaces the services of two SNCP rings due to fiber misconnections, and the fault is resolved after modifying the incorrect fiber connection method.
Product Description
OptiX OSN 3500
Failure Category
SNCP Failure
Phenomenon Description
OptiX OSN 3500 equipment network element C, using two sets of STM-1 optical ports to form two 155M SNCP rings, ring one on the Metro 1000 equipment network element A, ring two on the Metro 1000 equipment network element B, network element A and network element B have 2M tributary services are opened to the 2M tributary board ports 1 and 2, respectively, of the network element D. The networking diagram is shown in Figure 1.
The fiber of the Ring 1 and Ring 2 lines is cut, and after the cut is completed, there are no abnormal alarms or performance events in the transmission equipment, but the switching side reflects that the services of the base stations on Ring 1 and Ring 2 are interrupted.
Cause Analysis
- Service configuration error.
- Business loopback is not released.
- Fiber optic misconnection.
Operation Procedure
- Check the service configuration and find no problem, and the line cut does not change the transmission service, so exclude the service configuration error.
- Do external loopback on the 2M ports of Network Element A, Network Element B, and Network Element D respectively, and the switching side reflects normal, so the problem of equipment docking can be ruled out.
- Doing inner loopback on the 2M branch board service of network element A, and hanging the table on the corresponding 2M port of station D, a frame out-of-step alarm is found.
- De-activate the service of Network Element D corresponding to Network Element B. As a result, the APS reversal occurred in the tributary board of Station A, and the service of Station A was restored to normal, suspecting that the fiber was misconnected.
- By modifying the J0 byte to check the fiber connection between network element A, network element B and network element C, it is found that there are a pair of fibers in ring 1 and ring 2 on network element C, which are inconsistent with the fiber connection relationship of the equipment on the network management. As shown in Figure 2.
Figure 2 Misaligned networking diagram
- Reconnect the fiber according to the fiber connection relationship before the cut, and the fault is solved.
Reference Information
The fact that the device does not report alarms and performance events does not mean that the transmission side of the network is not faulty.
After the fiber cut involving the transmission side is completed, you need to carefully check the fiber connection relationship, and make sure to keep it consistent with the fiber connection relationship before the cut.
Use the meter diligently when dealing with faults, and take the results reflected by the meter as the basis.
The technical information in this chapter and the related SDH equipment troubleshooting procedures are provided by Shenzhen Optical Transmission Network Technology Company Limited (www.opticaltrans.com), and are reproduced with permission. Huawei SDH optical transmission equipment, SDH transmission equipment sales phone: 13430988088 Welcome to call!
