Administration: Stack Management : Stack Ports : Stack Port States
 
Stack Port States
Stack ports can be in one of the following states:
Down—Port operational status is down or stack port operational status is up, but traffic cannot pass on the port.
Active—Stack port was added to a stack LAG whose stack port operational status is up and traffic can pass on the port and it is a member of a stack LAG.
Standby—Stack port operational status is up and bidirectional traffic can pass on the port, but the port cannot be added to a stack LAG, and the port does not transmit traffic. Possible reasons for a port being in standby are:
- Stack ports with different speeds are used to connect a single neighbor.
- On the Sx550X/SG350, more than two interfaces or an unsupported interface combination is used to connect to a single neighbor