When the switch board CX310 of E9000 connect the S7700 ,the CPU usage will be very high and cp-car have many packets loss alarms,The bandwidth usage of corresponding interfaces are reaching 100%, When the server connect the switch ,on switch there are many alarms.
We can see many high CPU usage alarms ,MAC flapping alarms ,it seems that there is a loop in the S7700.
Topology is shown below , 2 switchboards CX310 from 1 server connect to the core switch S7706,And between the CX310,there is a cable connected them directly ,when I shutdown one of the interfaces on S7706 which is connected to server ,
There are still amount of alarms.
When login the CX310 to check the interface status ,I can see the bandwidth usage is 100% for this 10G port ,
But the strange thing is that another 40GE port on CX310 also has 98% bandwidth usage, so there may be a loop in the server internally.
There is a inner cable for 40GE port between 2 switch board CX310,so there is no need to connect a cable between them.Also on the CX310 switches ,the STP is not enabled causing the loop between 2 CX310.
By disconnected the cable or shutdown the interface and the alarms disappeared ,everything is recovery .
If Switch connect to server or other devices ,please make sure that there is no loop internally on those devices, or the loop will affect the service on switch.