Configuration notes for FastIron devices in a traditional stack

In a Brocade traditional stack system, a LAG may have port members distributed across multiple stack units. Both static and dynamic LAGs are supported.

The following notes apply to FastIron stackable devices that are part of a traditional stack:

• If a stack unit fails or is removed from the stack, its static LAG configuration becomes a reserved configuration on the Active Controller. Any remaining ports of the static LAG in the traditional stack continue to function.
• When a new stack unit is added to a traditional stack, the new unit receives the running configuration and LAG information, including a list of ports that are up and are members of a LAG, from the Active Controller.
• Before merging two traditional stack devices, make sure that there are no static LAGs configured between them. This can result in self-looped ports.
• You cannot configure a LAG between cross units in a mixed stack.
• When a traditional stack device with a static LAG partitions into multiple traditional stacks, loops and forwarding errors may occur. In these cases, user intervention is required to remove the loops.
• 10 Gbps links support up to eight ports in a LAG for stackable units.

The following figure displays an example of a valid, keep-alive LAG link between two devices. This configuration does not aggregate ports but uses the LACP PDUs to maintain the connection status between the two ports.

Figure 21  Example of a 1-port keep-alive LAG

The following figure shows an example of a valid 2-port LAG link between devices where the ports on each end are on the same interface module. Ports in a valid 2-port LAG on one device are connected to two ports in a valid 2-port LAG on another device.

Figure 22  Example of a 2-port LAG

The following figure shows an example of two devices connected over a 4-port LAG where the ports on each end of the LAG are on different interface modules.

Figure 23  Examples of a multislot, multiport LAG