Switch Stacks

Determining How to Stack

Stacking to Fit Your Network

Meraki Switches have multiple options to best fit your network deployment. This article discusses the Switch stacking features that can be leveraged to best suit your deployment, specifically: Virtual Stacking, Physical Stacking, and Flexible Stacking.

Understanding Virtual Stacking

With the Switching product, it's very easy to manage and deploy hundreds of switch ports on a network. This is made possible via the use of Virtual Stacking, which is the ability to easily push configuration to hundreds of switch ports in the network regardless of where the switches are physically located.

By entering a simple filter (refer to Searching for Ports section of this document), a network administrator can easily modify the required switch ports in just a few clicks.

Switch Port view in order to select stacking ports

Understanding Physical Stacking

Physical Stacking helps provide easy management and physical redundancy. Utilizing two physical stacking ports on the back of each switch, a stack can provide for gateway redundancy at layer 3 and dual-homing redundancy at layer 2. Only a single uplink is required to provide connectivity to the stack once all stacking cables are installed.

Cloud-managed Catalyst switches may take several seconds to resume passing traffic after the Active Member has failed due to the Meraki management container having to reinitialize on the new Active Member.

For step-by-step instructions, refer to the section of this article titled Configuring a Physical Switch Stack.

When a new switch stack is created, or a new switch is added to an existing stack, the below configurations will be removed from the stand-alone switch(es) and will need to be reconfigured on the stack:

Link aggregates
Mirrored switch ports
Switched virtual interface (SVIs)
Internet Group Management Protocol (IGMP) snooping (if switch specific settings are configured)
Maximum transmission unit (MTU) size (if switch specific settings are configured)
Spanning-Tree Protocol (STP) priority (if switch specific settings are configured)

Features like the ones above run one instance for the entire switch. When a stack is created, you are combining multiple physical switches all running their own instances of the feature to a single logical switch, which is why some features need to be reconfigured.

Understanding Flexible Stacking

Availability and redundancy are most helpful at the distribution layer of a network. On MS420 and MS425 series switches, any two switch ports can be configured as stack ports. This allows for full redundancy setup for your gateway and minimizes the impact of a failure in the network.

To achieve flexible stacking, go to Switching > Monitor > Switch Ports. Check at least two switch ports from the list. Select the Edit button > Stacking port > Enabled. Use the Name field to identify the stack ports as needed.

Configure Flexible Stacking

For step-by-step instructions, refer to the section of this article titled Configuring a Flexible Switch Stack.

Understanding how the Active Stack Member is Elected

If all stack members are powered up around the same time, the MS with the lowest MAC address will be elected the Active switch.
If the stack members are not powered up around the same time, the MS with the highest uptime will be elected the Active switch, regardless of its MAC address.
The Active switch will remain the Active switch until it's either rebooted or an event occurs that forces another Active switch election (such as stack ports being reconnected).

Stacking Availability

Unless specifically noted, only like-models, regardless of switch port density, can be stacked. For example, MS350-48 and MS350-24X can be stacked, but MS250-48 cannot be stacked with an MS350-48. The exception to this rule is for the C9300X which is backward compatible and will stack with c9300 series switches.

Model	Virtual Stacking	Physical Stacking	Flexible Stacking
MS120	Yes	No	No
MS125	Yes	No	No
MS130	Yes	No	No
MS210	Yes	Yes (Compatible with MS225)	No
MS220	Yes	No	No
MS225	Yes	Yes (Compatible with MS210)	No
MS250	Yes	Yes	No
MS320	Yes	No	No
MS350	Yes	Yes	No
MS355	Yes	Yes	No
MS390	Yes	Yes	No
C9300-M	Yes	Yes, Data + Power	No
C9300X-M	Yes	Yes, Data + Power	No
C9300L-M	Yes	Yes*, Data Only	No
MS410	Yes	Yes	No
MS420	Yes	No	Yes
MS425	Yes	No	Yes
MS450	Yes	Yes	No

*NOTE: Stacking the 9300L requires a stacking kit, it is not included by default. Please order a C9300L-STAK-KIT2-M with every C9300L that you plan on stacking.

For switches that support Physical/Flexible Stacking:

Stacking Cable Data Rate	Compatible Series
40 Gigabit	MS210 MS225 MS250 MS350 MS410 MS425
100 Gigabit	MS355 MS450
320 Gigabit*	C9300L
480 Gigabit / 1 Terabit	MS390 (480G) C9300 (480G) C9300X (1T with 480G backward compatibility)

*The C9300L does not include stacking ports by default. Please order the Stack-Kit (C9300L-STAK-KIT2-M) for each C9300L in the stack, the stack kit includes two stacking ports and a stack cable.

For full information about stacking cable compatibility, available options, and product IDs, see the Stacking Cables section of the SFP and Stacking Accessories datasheet.

Configuring a Physical Switch Stack

Up to eight switches can be configured in a physical stack to allow for high-speed communication between devices.

Only like-models can be stacked. For example, MS350-48 and MS350-24X can be stacked, but MS250-48 cannot be stacked with a MS350-48. The only exception is that MS210 and MS225 models can be members of the same stack.

Physical stacking is available on MS210, MS225, MS250, MS350, MS355, MS390, C9300/L/X, MS410, and MS450 switches, which include dedicated stacking ports. This section describes physical stacking.

Flexible stacking is available on MS420 and MS425 switches which do not have dedicated stacking ports; any switch port on these switches can be configured as a stack port. For flexible stacking, check the Configuring a Flexible Switch Stack section of this article.

Physical Switch Stack Configuration Steps

The steps below explain how to prepare a group of switches for physical stacking, how to stack them together, and how to configure the stack in dashboard.

Add the switches into a dashboard network. For that, you may follow Adding and Removing Devices from Dashboard Networks article. This can be a new dashboard network for these switches, or an existing network with other switches. Do not configure the stack in dashboard yet.
With all switches powered off and links disconnected, connect the switches together via stacking cables in a ring topology (as shown in the following image). To create a full ring, start by connecting switch 1/stack port 1 to switch 2/stack port 2, then switch 2/stack port 1 to switch 3/stack port 2 and so forth, with the bottom switch connecting to the top switch to complete the ring.

Stacking cables using full ring

3. Connect one cable to act as a single uplink from 1 switch of the stack. Power on all the switches, then wait several minutes for them to download the latest firmware and updates from dashboard. The switches may reboot during this process.

The power LEDs on the front of each switch will blink during this process.
Once the switches are done downloading and installing the firmware, their power LEDs will stay solid white or green.

4. Dashboard will now automatically attempt to provision detected potential stacks for you. This has the same effect as clicking the "Provision this stack" button, and Dashboard will only attempt this once. If Dashboard is unable to auto provision the stack, the switches will appear on the same page in the Detected stacks that failed auto provisioning section, and the stack will need to be manually provisioned using the Provision this stack button once the cause of the provisioning failure has been fixed.

Provision this stack view

When rebooting a stack member from the dashboard using the "Reboot device" tool will reboot only that individual stack member. The same applies when performing a factory reset on a stack member. This does not apply to MS390 or C9300/L/X stacked switches, for the behavior of these models please refer to the section Stacking Catalyst Switches

Creating a stack manually

If Dashboard does not detect the potential stack, you can configure the stack manually. Navigate to Switching > Monitor > Switch stacks. Click the link to add one or the Add a stack button, depending on the option available: Provision this stack view

Next, select the checkboxes of the switches you would like to stack, enter a name for the stack, and click Create.

create new stack

Validate the switches are now successfully stacked via Switching > Monitor > Switch Stacks

6. If unsuccessful, review and correct the error and reattempt provisioning.

NOTE: After the switch stack is up and running, multiple uplinks can be added for redundancy.

Stacking Catalyst (MS390s / C9300-M / C9300X-M)

Follow the steps below to setup a MS390/C9300/C9300X stack or watch Cisco Meraki MS390 Stack Setup Walkthrough video.

Add the switches into a dashboard network. For that, you may follow Adding and Removing Devices from Dashboard Networks article. This can be a new dashboard network for these switches, or an existing network with other switches. Do not configure the stack in dashboard yet.
With all switches powered off and links disconnected, connect the switches together via stacking cables in a ring topology (as shown in the following image). To create a full ring, start by connecting switch 1/stack port 1 to switch 2/stack port 2, then switch 2/stack port 1 to switch 3/stack port 2 and so forth, with the bottom switch connecting to the top switch to complete the ring. While connecting the stacking cables, ensure that each connector is correctly aligned to the switch's stacking port it is connecting to and finger-tighten the screws (clockwise direction). Make sure the Cisco logo is on the top side of the connector.
Connect one uplink for the entire switch stack. Power on all the switches, then wait several minutes for them to download the latest firmware and updates from dashboard. The switches may reboot during this process.
Download the same firmware build using the Firmware Upgrade Manager under Organization > Monitor > Firmware upgrades, if they are not already set for this. This helps ensure each switch is running the same firmware build. Please note that it might take close to an hour for the switches to upgrade.
Navigate to Switching > Monitor > Switch stacks
Configure the switch stack in dashboard. If dashboard has already detected the correct stack under Detected potential stacks, click Provision this stack to automatically configure the stack. Otherwise, click the link to add one or the Add a stack button, depending on the option available:

It is expected that not all member switches will appear online until the stack is fully configured in the dashboard, as instructed in step 6.
Based on the number of members in a stack, the switch stack may require approximately one hour to become operational and connect to the Meraki Dashboard.

The MS AutoStacking process applies to MS390s and C9300/L/X as well, please see the note above regarding auto provisioning.

Select the checkboxes of the switches you would like to stack, name the stack, and then click Create.

switch stack view

7. Ensure that all switches have downloaded the latest configuration. To verify this, navigate to Switching > Monitor > Switches and select the MS390 switch. Look for CONFIG in the column on the left of the switch details page and check if the status reads Up to date.

When using static IP addressing for switch management interfaces rather than DHCP, the management IP address cannot be individually altered for each stack member through the dashboard. Once the stack is configured, all members will display the management IP address of the active (primary/master) switch, where the control plane resides. It is important to note that if a change to the management IP is made after the stack has been configured, that change will apply to the active switch and will be reflected across all stack members. The management IP is shared and not unique to each switch within the stack.

Note: Due to the management IP behavior described above, accessing the Local Status Page from any member will direct to the local status page of the active switch, regardless of which stack member you are physically connected to.
Based on the number of members in a stack and switch ports being used boot time can vary.
Rebooting a stack member from the dashboard using the "Reboot device" tool will reboot all the members in a stack. The same applies when performing a factory reset on a stack member.
Physically power cycling switch stack members may cause other stack members to be unreachable for a short time, while the management plane re-initializes.

Adding a new member to the stack

Add the new switch into a dashboard network of the existing switch stack. For that, you may follow Adding and Removing Devices from Dashboard Networks article.
Connect the new switch to an uplink to bring it online and ensure it checks in with the Meraki dashboard.
Upgrade the switch to the same firmware build as that running on the switch stack, using the Firmware Upgrade Manager under Organization > Monitor > Firmware upgrades,
Before adding the new member to an existing stack make sure the total number of VLANs is limited to 1000. E.g If you have an existing stack with each switch port set to Native VLAN 1, 1-1000 and the new member switch ports are set to native VLAN 1; allowed VLANs: 1,2001-2500 then your total number of VLAN in the stack will be 1000(1-1000)+500(2001-2500) = 1500. Dashboard will not allow the new member to be added to the stack and will show the following error:

Stack alert due to using over 1000 VLANs

Navigate to Switching > Monitor > Switch stacks and select the existing stack you want to add the switch to.
Check that the switches in the existing stack have all fetched the new configuration. To verify this, navigate to Switching > Monitor > Switches and select a switch in the stack. Look for 'Configuration status' in the column on the left of the switch details page and check if the status reads 'Up to date'.
In Switching > Monitor > Switch stacks > Manage members add the new switch to the existing stack.
Power off the switch and physically stack the new switch to the existing stack in a ring fashion.
Power on the new member.

Note: Please ensure to remove any layer 3 interface from a switch, before attempting to add it as a new member to a stack with existing layer 3 interfaces. If not, you will get the following error: ERROR "Cannot add a switch with layer 3 interfaces to a stack with layer 3 interfaces".

Configuring a Flexible Switch Stack

Up to eight Meraki MS420/425 switches can be configured in a flexible stack to allow for high-speed communication between devices.

Flexible stacking is available on MS420 and MS425 switches, which do not have dedicated stacking ports. Any SFP+ interface on these switches can be configured as a stack port. On the MS425, the QSFP+ ports can also be configured as stack ports. Please note that 10 Gb/s is the minimum speed required to support flexible stacking. This section describes flexible stacking.

Only like-models can be stacked. For example, MS350-48 and MS350-24X can be stacked, but MS250-48 cannot be stacked with a MS350-48.

Physical stacking is available on MS210, MS225, MS250, MS350, MS355, MS390, MS410, and MS450 switches, which include dedicated stacking ports. For physical stacking, check the Configuring a Physical Switch Stack section of this article.

On the MS420 and MS425 series switches, you have the flexibility to use any of the front switch ports as either ethernet (default) or stacking. This option is available under the port configuration and can be easily modified by just selecting enable from the dropdown.

Enable stack configuration

Converting a link aggregate to a stacking port is not a supported configuration and may result in unexpected behavior.

Once this configuration is made and the switches have downloaded the new configuration it's recommended to follow a similar ring topology as mentioned above for the overall switch port cabling. Switch ports configured as stack ports will show up with a new symbol on the nodes status page to indicate that it's configured for stacking.

Switch GUI on dashboard

Flexible Switch Stack Configuration Steps

The following steps explain how to prepare a group of switches for flexible stacking, how to stack them together, and how to configure the stack in dashboard:

Add the switches into a dashboard network. This can be a new dashboard network for these switches, or an existing network with other switches. . For that, you may follow Adding and Removing Devices from Dashboard Networks article. Do not configure the stack in dashboard yet.
Connect an uplink to each switch. Ensure that the uplink switch ports are different than the intended stacking ports.

Power on all the switches, then wait several minutes for them to download the latest firmware and updates from dashboard. The switches may reboot during this process.
- The power LEDs on the front of each switch will blink during this process.
- Once the switches are done downloading and installing firmware, their power LEDs will stay solid white or green.
Choose (but do not yet connect) two switch ports per switch to be the dedicated stacking ports. Switch stacks should be connected in a ring topology (as shown in the following image). Ensure that the stacking ports are different than the switch uplink switch port. Do not actually connect the switch ports yet. This will be done in Step 6.

Ring stacking scheme

It is recommended to configure and use identical switch port types as flexible stacking ports. For example, 2 x 10Gb/s (SFP+) or 2 x 40Gb/s (QSFP) interfaces can be connected together as flexible stacking ports.

Please note that 10 Gb/s is the minimum speed required to support flexible stacking.

Configure the intended switch ports for stacking in dashboard under Switching > Monitor > Switch ports:

Stack configuration enable on port

Connect the switch stack via the intended stacking ports like the image shown in step 4.
Navigate to Switching > Monitor > Switch stacks.
Configure the switch stack in dashboard. If dashboard has already detected the correct stack under Detected potential stacks, click Provision this stack to automatically configure the stack.
Otherwise, to configure the stack manually:

The MS AutoStacking process applies to flexible switch stacks as well, please see the note above regarding auto provisioning.

Navigate to Switching > Monitor > Switch stacks.
Click add one / Add a stack:

Configure the switch stack in dashboard

Select the checkboxes of the switches you would like to stack, name the stack, and then click Create.:

Create New Stack

Disconnect all but one switch's uplink, which will be the uplink for the switch stack.

Viewing and Creating Your Stacks

The Switch Stacks Page gives you quick access to all of the configured stacks in the network as well as provides easy configuration options for new Stacks that are being deployed. Clicking on "Add a stack" or when there is a detected stack you'll be able to easily configure a new physical stack.

Switch Stacks overview

Potential stacks

Check the Health of the Stack

Viewing a Stack

In order to check the stack status visually simply click any row on the Stacks List. This will take you to the Overview of the stack selected. From here you can easily get a feel for connected switch ports and which switches are contained in the stack. We've included the capability to blink the LEDs on switches in the stack to easily indicate which switch it is for anyone who's on site looking at the stack.

Stack Members

Managing Stack Members

To add or remove Stack Members simply click on the Manage Members tab and select the switch/es that you want to add or remove from the stack and click either add or remove switches.

Add and remove stack members

Viewing Switch Stack Role info

When using physical or flexible stacking, one switch in the stack acts as the active switch, managing all of the stack functions such as spanning-tree. It may occasionally be useful to understand which switch is the active switch and which are stack members.

Beginning with MS 15.18, the stack role is displayed on the switch details page for an individual switch accessed from the Switching > Monitor > Switches page if the switch in question belongs to a switch stack. The "switch stack" section of the left-hand column displays one of three stack roles:

Active
Standby
Member

Switches other than the MS390 have one active switch in the stack and all other switches are member switches.
MS390 stacks also have one standby switch. The standby becomes the active unit in the event of a failure of that switch.

Switch Stack Role

Replacing and Cloning Stack Members

The steps below should be used for the following use cases:

Replacing a Stack Member
- A stacked switch has failed and needs to be replaced.
- A stacked switch needs to be replaced in a stack with 8 switches.
Cloning a Stack Member
- A stacked switch needs to be replaced, but the new switch should be up and running before the replacement occurs.
- A new switch needs to be added and requires the same switch port configurations of another stack member.

Note: All the following instructions are the same for both physical and flexible switch stacks.

Replacing and Cloning a Stack Member Video

Replacing a Stack Member

The following steps will clone the original stack member and remove it from the stack:

Note: If the Active stack member is replaced there will be a short loss in connectivity when it is powered down while a new Active member is elected.

Power off the stack member to be replaced
Claim the new/replacement switch in the inventory (Using the Organization Inventory):

Navigate to Organization > Inventory
Click the Claim button
Enter the serial number of the new switch. If replacing multiple members, list all serials

Claim by serial number

Click Claim

Add the switch to the network containing the stack

Select the switch to be added to the network
Click Add to...
Select the network and Add to existing

Note: After the switch has been added to the network and before it is added to the stack or replaced, it should be brought online individually and updated to the same firmware build as the rest of the stack. Failing to do so can prevent the switch from stacking successfully. The configured firmware build for the network can be verified under Organization > Firmware Upgrades. A flashing white or green LED on the status light on the switch indicates that a firmware upgrade is in progress.

(Optional) Edit the name of the new switch

Navigate to Switching > Monitor > Switches
Select the new switch
Click the next to the title to rename the switch

Clone and replace the stack member

Navigate to Switching > Monitor > Switch stacks
Select the existing stack
Navigate to the Clone and replace member tab
Select the source switch to be replaced
Select the destination switch which will replace the source switch

Clone and replace stack member

Click Clone switch

Physically swap the switches

The old switch can then be repurposed as a standalone switch or removed from the network (Adding and Removing Devices from Dashboard Networks).

Cloning a Stack Member

The following steps will clone the original stack member without removing it from the stack.

Claim the new/replacement switch in the inventory:

Navigate to Organization > Inventory
Click the Claim button
Enter the serial number of the new switch. If replacing multiple members, list all serials

Claim by serial number

Click Claim

Add the switch to the network containing the stack

Select the switch to be added to the network
Click Add to...
Select the network and Add to existing

(Optional) Edit the name of the new switch

Navigate to Switching > Monitor > Switches
Select the new switch
Click the next to the title to rename the switch

Clone the stack member

Navigate to Switching > Monitor > Switches
Select the replacement switch
Click on Clone as highlighted below

Clone switch

Search for the original stack member name or mac address and select it.

Clone selection

Click Clone.

Submit clone

Add the new switch to a stack.

Navigate to Switching > Monitor > Switch stacks
Select the existing stack
Navigate to the Manage members tab. In the Add members section, select the switch to add
Click Add Switches

Switch Replacement Walkthrough for Stacks Bound to a Template

Below are instructions for how to copy configurations from a failed switch that is part of a stack and where the network is bound to a template.

On the Organization > Configure > Inventory page, claim the new switch and then add the new switch to the existing network.

Bind new switch to the switch template.

Navigate to the parent template in dashboard.
Navigate to Switching > Configure > Switch templates within that template.
Click on the corresponding template.
Click the Bind switches button.
Click the checkbox next to the new switch and click the Bind to switch template button.

Firmware upgrade for the new switch.

Provide the new switch a physical uplink connection and then power it on. The new switch needs to be brought online as a standalone device, not yet added to the stack so that it can update its firmware.
Confirm via the connectivity graph or Support that the switch has upgraded its firmware.
While the new switch upgrades, you may proceed with the below steps, stopping before Step 8 until the new switch has had a chance to upgrade.

Obtain Current Configuration.

Navigate to Switching > Configure > Switch templates within the parent template.
Click on the template in question.
Filter in the Search switches… field for the name of the old switch.
Note the local override configuration. Save in a text editor for use in Step 5.

In the child network, navigate to the Switching > Monitor > Switch ports page.
In the Search switches… field, filter by the name of the old switch and select the below column options.

Then, take screenshots of the port configurations or copy and paste into a spreadsheet or text editor application.

Configure replacement switch.

On the Switching > Monitor > Switch ports page of the child network, configure the switch ports of the new switch based on the configuration gathered in Step 4.
Once complete, navigate back to the switch template details page from Step 4 and ensure that the local overrides between the old and new switch match.

Power down the old switch.
Unbind Old Switch from template.

On the switch template details page, click the check box next to the old switch and then click the Unbind button.

Add the new switch to the stack.

After confirming that the new switch has upgraded its firmware as mentioned in Step 3, power down the new switch.
In the child network, navigate to the Switching > Monitor > Switch stacks page.
Click on the stack in question.
Click the Manage members tab.
Under Add members, click the checkbox next to the new switch and then click the Add switches button.

Remove the old switch from the stack.

In the child network, navigate to the Switching > Monitor > Switch stacks page.
Click on the stack in question.
Click the Manage members tab.
Click the checkbox next to the old switch and then click the Remove switches button.

Physically cable and stack the new switch.

Power on the new switch.

Layer 3 Interface Configuration

For configuration details and caveats regarding layer 3 switch stack routing, please reference the article MS Layer 3 Switching and Routing.

Common Alerts

Ensure all stack members are configured on dashboard, online and connected via their stacking ports.

Note: If connected and configured correctly, the alert will disappear within up to 1 hour. If the error persists, please contact Cisco Meraki Technical Support for further troubleshooting.

This switch's current stack members differ from the dashboard configuration.

This switch's current stack members differ from the dashboard configuration

This error can occur in the following scenarios:

Stack members are configured on dashboard, but not all members are connected via their stacking ports.
A stack member has failed or is powered off.

This switch is not connected to a stack.

This switch is not connected to a stack

This error can occur in the following scenarios:

The switch is configured on dashboard as a stack member, but is not connected to a stack.

This switch does not have a stack configuration.

This switch does not have a stack configuration

This error can occur in the following scenarios:

The switch is physically connected as a stack, but not configured on dashboard as a stack member.