Fault Symptom
The NE80E/40E serves as the access device. When the PPPoE subscriber tries to access the network through the NE80E/40E, the system prompts error code 678. The networking diagram is as follows:
Fault Analysis
1. Run the trace object mac-address mac-address command to trace the MAC address of the PPPoE subscriber who fails to dial up with an error code 678. The command output shows that the PPPoE subscribe can receive the PADI packet and send the PADO packet. It can thus be concluded that the link is normal.
2. Run the display access-user interface interface-type interface-number command on the interface where the fault occurs. The command output shows that other users can access the network through this interface. It can thus be concluded that the device configuration is correct.
3. Get packets head on the outbound interface of the switch SwitchB. The result shows that the PADO packet has been sent from the outbound interface but is discarded during the transmission process. As a result, the user side does not receive the PADO packet.
4. Check the transmission device. The result shows that its minimum transmission unit is 64 bytes, and the length of the PADO packet, however, is smaller than 64 bytes. As a result, the PADO packet is thus discarded by the transmission device and the system prompts error code 678.
Procedure
1. Run the system-view command to enter the system view.
2. Run the sysname host-name command to lengthen the PADO packet.
Summary
The PADO packet has an AC_NAME field, which is filled with the name of the NE80E/40E. When the PPPoE subscriber fails to dial in and the system prompts error code 687, you can rectify the fault by changing the name of NE80E/40E to ensure that the length of the PADO packet is greater than the minimum transmission unit of the transmission device.
