How to capture packets for troubleshooting on GPON OLT P1201?

03-17-2022
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Note: This Article Applies to: TP-Link GPON OLT P1201; Archer XR500v

If you have some issues with the OLT and ONU devices, but cannot find the root reason. You may need to capture some negotiation packet to help analyzing now. It’s a common method during the network problem troubleshooting. So how can we do that on the OLT side and ONU side?

From OLT side, you need to use the Port Mirror function to achieve that.

A: CLI

When it is needed to copy the flow of a port to output in another port, or used to flow monitoring and network fault diagnosis, use this command.

ONT(config)interface ge 0/0 
OLT(config-interface-ge-0/0)# mirror src-port <src-port-id> dst-port {ge|xge <F/S/P>} {all|egress|ingress}

 
ONT(config)interface gpon 0/0
OLT(config-interface-gpon-0/0)# mirror src-port <src-port-id> dst-port {ge|xge <F/S/P>} {all|egress|ingress}

You need to run the packets capture software like Wireshark at the dst-port. After that, you will capture all the packets from src-port.

B: EMS

You can also use the EMS to configure the port mirror.

Go to Control Card Management, click SwitchCard Mirror. Then choose the Source port and Destination port.

C: ONU side

Sometimes, we are not at the OLT side, which means we cannot arrange a PC connected to the OLT device. TP-Link ONU can support the port mirror function too. So we can capture the packets from ONU side.

Step1. Open the windows telnet service.

Step2. Open the CMD and input telnet 192.168.1.1(default IP of the ONU)

Step3. Input username and password of the DUT to login.

Step4. Input sh, then press Enter.

Step5. Input sys wan2lan on, then press Enter.

After that, you can receive all the WAN side packets from LAN port. Just run the Wireshark to capture it. Set the filter as: omci_mtk to check the communication between OLT and ONU.

Note:

The command are only for special model, Archer XR500v. Not suitable for all the other ONUs.