Stacking

The stacking function connects multiple stacking-capable devices together to logically function as one device. Up to nine devices can be connected through stack cables in a ring or bus topology. All stacked devices logically function as one device to forward packets. There are three roles of the devices in a stack: master switch, standby switch, and slave switch. All of the three types of switches are called member switches. The Ethernet switches in a stack function as a device. You can manage all the switches in a stack by using the master switch. S2700EI, S2700EI-52P or S2700SI switches do not support the stacking function.

Context

After the stacking function is enabled on a switch and another switch attempts to connect to this one, if the configurations that the stack does not support exist on the stacking-enabled switch, the system displays a message indicating that some configurations are not supported by the stack. As a result, the new switch cannot be added to the stack. The new switch can be added to the stack only after these configurations are deleted.
Before the stack is established, each switch is an independent entity. Each switch has its own IP address and functions individually. Therefore, you need to manage each switch separately. After the stack is established, all the member switches are presented as one unified logical entity. In this manner, you can manage and maintain all the member switches in a stack by using one IP address. The stacking protocol elects the master switch, standby switch, and slave switch in a stack. Then, data can be backed up and the active/standby switchover can be implemented.

Procedure

Configure the stack.

Choose System Management > Stacking in the navigation tree to open the Stacking page.

Table 1 describes the parameters on the Stacking page.

**Table 1** Stacking
Parameter	Description
Stack Topology Type	Indicates the topology type of the stack. This parameter cannot be set.
Stack System MAC	Indicates the MAC address of the stack. This parameter cannot be set.
Stacking	Indicates whether to enable the stacking function on the interface. The options are Enable and Disable. By default, the PoE function is enabled. NOTE: If the stacking parameters are set before you enable the stacking function, you must restart the device to make the parameters effective. On the S6700 switches, this parameter has a fixed value Enable.
MAC Switch Delay Time	Indicates the delay of MAC address switching. This parameter takes effect immediately. After a switchover occurs between the master and slave switches, the MAC address of the stack is switched to be that of the newly-elected master switch if the previous master switch does not rejoin the stack after the switchover times out. The MAC address switchover time of any member switch in a stack is the same as that of the master switch. NOTE: By default, the delay of the MAC address switchover is 10 minutes. If the value of the MAC address switchover timer is set to 0, it indicates that MAC address switchover will not be performed.
Stack Reserved VLAN	Indicates the reserved VLAN of the stack. By default, a stack specifies VLAN 4093 as the reserved VLAN. A reserved VLAN is used for exchanging the stack protocol packets only.

Set the parameters.
Click OK.

Modify the stack.

Choose System Management > Stacking in the navigation tree to open the Stacking page.

Click

to open the Configure Stack page.

Table 2 describes the parameters on the Configure Stack page.

**Table 2** Configure Stack
Parameter	Description
Current Stack ID	Indicates the stack ID. This parameter takes effect after the device is restarted. Stack IDs can be configured before or after the stack is established. By default, all the stack IDs of member switches in a stack are 0. If stack IDs are not configured for member switches before the stack is established, the stack assigns stack IDs to member switches after being established. After the stack is established successfully, all the configurations of the stack can be performed on the master switch only.
Priority	Indicates the priority of the stack. The stack priority can be configured before or after the stack is established. If the stack is established, this parameter must be set on the master switch; otherwise, it is set on each switch.

Set the parameters.
Click OK.