Troubleshooting.

A bureau uses Huawei OSN3500 and OSN1500 devices to organize the network, and uses the EFS0 single board to configure the Ethernet LAN service with shared bandwidth; the service is normal at individual sites, but the service is not available at most of the sites, and there are no abnormal alarms on the devices.

Introduction to Networking:

The above figure shows the network of a bureau, using OSN3500 and OSN1500B mixed networking, using MSP ring protection, ring 1 and ring 2 are accessed through an aggregation node to converge the upper layer network. A service requires that all network elements and network element 1 on ring 1 and ring 2 have to interoperate, in order to save the bandwidth of the ring network, so it is configured as a shared PORT port Ethernet LAN service, the business model is as follows:

Site	Network element 1	Network element 2	Network element 3	............	Network Element 26
LAN Service	PORT1←→VCTRUNK2	PORT1→VCTRUNK4			PORT1←→VCTRUNK3
		PORT1→VCTRUNK3	PORT1→VCTRUNK4

A screenshot of the service configuration at a site on the current network is shown below:

Cause Analysis.

1. Customer-side equipment failure;

2. Failure of network cable and electric module;

3. Service configuration error: time slot or port attribute setting error;

4. Ethernet single board port failure;

5. Ethernet single board failure.

Fault location handling process:

1. Checked the ports of the customer-side equipment and restarted the customer-side equipment, and the service is still not available, so the customer-side equipment failure is ruled out;

2、 Tested the network cable and electrical module connected to the customer side is normal, to rule out the network cable and module failure;

3, ping test on the customer side of the network element, network element 1 and network element 2 ping test is normal, network element 2 and network element 3 ping can not be, initially located in the fault occurs in the network element 2 and network element 3, check the network element 2 and network element 3 business configuration, port attributes and operating mode settings are normal, the Ethernet frame test, the received frame and the transmission of frames is consistent with the determination of the SDH channel is normal, locate the fault in the network element 2 or network element 3. It is determined that the SDH channel is normal, and the fault is localized in Network Element 2 or Network Element 3;

4. Conduct ping test on the service side of Network Element 2 and Network Element 3, and observe the RMON performance of the port ports at both ends on the network administrator, and find that there are only receive packets but no transmit packets in Network Element 2, and there are only transmit packets but no receive packets in Network Element 3, and further locate the fault in the EFS0 boards of Network Element 2 or Network Element 3;

5. Replace the ports between Network Element 2 and Network Element 3, and configure a new Ethernet private line service to hang up the table again to test and observe the RMON performance, and find that Network Element 2 only receives packets but does not send packets, and Network Element 3 sends packets and receives packets, basically ruling out the failure of the EFS0 single-board ports, and further localizing the failure of the Huawei N5EFS0 single-board of the Network Element;

6, in the network element 2 to change a slot Huawei OSN1500 N5EFS0 single board and network element 3 of the original EFS0 single board configuration of an Ethernet private line service, hanging table test and observe the RMON performance, found that the network element 2 only receive packets without sending packets, network element 3 have to send packets and receive packets, initially concluded that the network element 3 of the EFS0 single board faults, due to the network element 3 of the SSN5EFS0 board adopts TPS protection, the EFS0 board of network element 3 is inverted to the protection board, and the ping test between network element 2 and network element 3 is normal, and the EFS0 of network element 3 is inverted back to the working board, and the ping between network element 2 and network element 3 is not available, so it can be determined that the working N5EFS0 board of network element 3 is faulty;

7. Invert the EFS0 of network element 3 to the protection single board, and carry out the service test, and the service is back to normal.

Recommendations and summary

For Ethernet service interruption faults, especially multi-point Ethernet service interruption faults, the first step is to locate the fault point, or first external, then internal; first network, then network elements, and then locate the specific single board or port. Although it is more complicated to deal with multi-point Ethernet service failure, you can still locate and deal with the failure point step by step according to the troubleshooting methodology.

The technical information and SDH equipment troubleshooting procedures in this chapter are collected and organized by Shenzhen Optical Transmission Network Technology Company Limited ( www.opticaltrans.com), please retain! Our company specializes in the sale of Huawei SDH optical transmission equipment,SDH transmission equipment.