Administration: Stack Management
Stack Ports
127
Cisco Sx350, SG350X, SG350XG, Sx550X & SG550XG Series Managed Switches, Firmware Release 2.2.5.x
7
•
X Devices
—The four XG uplink ports can be stack ports.
Stack Port Link Aggregation
When two neighboring units are connected with multiple stack links, the stack ports
connecting them are automatically assigned to a stack LAG. This feature enables increasing
the stack bandwidth of the stack port beyond that of a single port.
There can be up to two stack LAGs per unit.
The stack LAG can be composed of between two and up to the maximum number of stack
ports depending on the unit type.
On the Sx550X/SG350 devices, up to two interfaces can compose a stacking LAG between 2
units. The allowed interface combination for the same stacking LAG is either interfaces XG1
and XG2 or interfaces XG3 and XG4. Other combination of interlaces in the same stack LAG
is not supported.
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
Physical Constraints for Stack LAGs
The following factors constrain the use of stack LAGs:
•
A stack LAG must contain ports of the same speed.
