NE40 is upgraded from version 2226 to 2317, and L2 LPU E4GC and part of ports of 16FE interface board cannot interact. Check the failed ports, and the connected at peer is a switch of which the interconnecting interface enables STP. The port is in BLOCK state.
1. Check the status of port, and that of NE40 is normal; check the status of VLAN interface, and it is also normal. The local equipment is configured well.
2、Check the equipment at peer, and it is found that the STP at its port is in BLOCK state.
3. Check if NE40 has a loop, but it is normal.
4. According to packets captured between the switch and NE40, it is found that NE40 has duplicated the STP packets received from the switch, and then forwards it the switch through the original port.
5. Shut down the STP at the relevant ports of switch, and services could communicate.
The L2 LPU of NE40 at version 2317 fails to process the STP packet after receiving it. The port of the L2 LPU will duplicate the STP packet and forwards it out through the port, resulting in that both switches at two sides receive the STP packets they transmit out; it is thought that a loop occurs to network, and the port is set to BLOCK, making the network crash.
It is suggested to load the patch of SP03 during upgrading NE40 to version 2317, solving the problem from STP packet processing.
If it is hard to load patch, disable the STP at the port of switch connecting with NE40 to avoid the problem.