Description of the problem

Huawei OSN3500 device EGT2 single board, configure EPL service, connected to the number of communication switch network, the entire network requires loop detection, the switch device to enable the STP protocol, after replacing the N2EGT2 for the N4EGS4, the switch has a LOOP alarm, industry

Processing

The functions and characteristics of the Huawei OSN3500 device EGT2 single board can be known:

Provides 2-way GE transparent transmission, supports EPL, supports transparent transmission of VLANs, and does not support STP and RSTP protocols. In short, all the data messages passing through the EGT2 single board, the EGT2 single board does not do any processing, transparent transmission, this issue we are concerned about the regeneration tree protocol messages are also transparent transmission without any processing.

The functions and characteristics of the EGS4 veneer can be known:

Provides access and processing of 4-way GE services. It supports transparent transmission of EPL services based on PORT, VLAN and QinQ, adding, deleting and exchanging VLAN tags, and STP and RSTP protocols. In short, the data passing through the single board of EGS4 can support the transparent transmission of the created EPL service, but because the single board supports STP and RSTP protocols, the STP and RSTP protocol messages passing through the single board will be detected and processed accordingly. In this problem, because the STP and RSTP protocols are not enabled on the EGS4 board in the current network, when the external port receives STP and RSTP protocol messages, they are processed as business messages without transmitting LACP messages, and because the STP and RSTP protocol message format is different from the ordinary business message format, they are eventually discarded. As a result, the remote switch and router cannot receive STP and RSTP protocol messages, and there is a loopback situation on the physical link, which will not activate the Spanning Tree Protocol, and it will cause the loopback of the service.

Lab EGT2 replaced with EGS4 verifies that the results work: OSN3500 and OSN2500 base on version 5.36.18.50.

The solution

Solution 1 :

Replace the EGT2 board with a board that does not support STP and RSTP protocols.

Option 2 :

Replace EGT2 with an EGS4 single board to de-enable the ingress detection of the EGS4 port.

From the table below, we can see that when port detection is not enabled, STP and RSTP protocol messages are transmitted, which is exactly what we require.

Option 2 is used in this case.

Recommendations and Summary

Before replacing the veneer, pay attention to check the functions and features of the veneer and the veneer version.

Huawei OSN3500 device N4EGS4 replaces N3EGT2, causing the switch to have LOOP alarms. In addition, if the service is with VLAN, and the TAG attribute of the EGS4 port is set incorrectly, the service may not be available.

The single board version does not match the host version of the device, which may cause false alarms, single board offline and many other situations.

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