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.

Context

A stack can be set up using service interface connections or stack card connections.
- The following models support service interface connections: S2750, S5700-P-LI (with GE uplink interfaces), S5700-X-LI (with 10GE uplink interfaces), S5710-EI, S5700-HI, and S6700. The stacking function is not supported on the S5700-28P-LI-BAT, S5700-28P-LI-24S-BAT, S5700-10P-LI-AC and S5700-10P-PWR-LI-AC in the S5700-P-LI series (with GE uplink interfaces).
  NOTE:
  A stack of S5700-52X-LI-48CS-AC switches cannot be managed by the web-based network management system.
- The following product models support service card connections: S5710-LI series, S5700-SI series (except the S5700-26X-SI-12S-AC), and S5700-EI series.
When a switch attempts to set up a stack with a switch enabled with the stacking function but the stacking-enabled switch has some configurations that the stack does not support, the new switch cannot join the stack and 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.

NOTE:

The actual display varies depending on the device model.

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.
MAC Switch Delay Time	Indicates the delay of MAC address switching. This parameter takes effect after the device is restarted. 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 MAC address switchover timer is disabled. The system performs the MAC address switchover immediately after the active/standby switchover occurs between switches. 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

, the Configure Stack page is displayed.

NOTE:

The actual display varies depending on the device model.

Table 2 describes the parameters on the Configure Stack page.

**Table 2** Stack Settings
Parameter	Description
Next 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.
Next Startup Priority	Indicates the priority of the stack. This parameter takes effect after the device is restarted. 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.

Select the list of logical interface. This step can be performed only on the product models that support service interface connections.

Click the standby switch or master switch of the list of switch role. The selected physical stack interfaces of the switch are displayed in the list of logical interface.

Click the

icon, the Configure Stack Interface page is displayed.

Table 3 describes the parameters on the Configure Stack Interface page.

**Table 3** Stack Interface Configuration
Parameter	Description
Logical Interface Name	Indicates the name of the logical interface on the device.
Selected Physical Stack Interfaces	Selects an interface as the physical stack interface.

Selects the name of the interface that functions as a stack interface.
Click OK.
Return to the Tacking page, and click Apply.