StackWise Technology

StackWise Technology was invented to address the challenges of managing multiple switches in growing enterprise networks. Traditionally, each switch had to be configured and monitored separately, which was time-consuming and error-prone. StackWise simplifies this by allowing multiple switches to be managed as one logical unit with a single IP address and configuration. It also improves scalability by making it easy to add new switches to the stack without disrupting the network.

In terms of performance and reliability, StackWise uses high-speed stack cables that offer much faster inter-switch communication than traditional Ethernet uplinks, and it provides redundancy through its ring topology, if one switch or cable fails, traffic reroutes automatically. Finally, it enhances uptime by enabling automatic master-switch election if the original master fails, ensuring continuous operation without manual intervention. We will explain this technology and its features in this article, be with us.

StackWise Technology:

StackWise is a Cisco proprietary technology that allows you to connect multiple Cisco Switches together to function as a single logical switch. This is mainly used in enterprise networks to simplify management and improve resiliency and scalability. This technology was introduced in Cisco Catalyst 3750 Series first.

How StackWise works?

• Physical Connection: Switches are connected using special stack cables through dedicated StackWise ports (not Ethernet). These cables create a ring topology each switch connects to the next and the last one connects back to the first, forming a loop.
• Logical Satck Formation: Once physically connected, the switches negotiate and elect a master switch and All switches operate under the control of the master, sharing a single configuration and control plane.
• Control and data planes: Control Plane, Handled by the master switch (responsible for configuration, routing decisions, spanning-tree, etc.) and Data Plane, Each switch still handles its own traffic forwarding, but all decisions come from the master.
• Management: The entire stack is managed as a single switch, with one IP address and You can SSH, Telnet, or access it via SNMP as if it were one device.

StackWise Versions:

There are several versions of StackWise technology, including StackWise-32, StackWise-160, StackWise-480 and StackWise Virtual. These versions differ in bandwidth capabilities and how they connect. For example, StackWise-480 supports up to 480Gbps of stack bandwidth and is used in more advanced models like the Catalyst 3850 and 9300 series.

StackWise Virtual, unlike traditional StackWise, doesn’t require special stack cables and instead allows two switches to form a logical stack over standard Ethernet uplinks like 10G or 40G links. This is useful when switches are physically located in different places (e.g., different racks or floors).

Benefits of StackWise:

• Simplified Management: One switch to manage instead of many.
• Increased Uptime: If one switch fails, the others continue functioning.
• Scalability: Add switches without changing IP or config.
• High Speed: Stack cables allow fast inter-switch communication.
• Redundancy: Ring topology allows loop protection traffic can flow both directions.

Limitations of StackWise:

• All switches must support StackWise Technology and use compatible stack cables.
• Limited to certain Cisco models (mostly Catalyst switches).
• Adding/removing switches can require careful planning to avoid downtime.
• Master switch failure causes a short failover period while a new master is elected.
• Stack members usually need to run the same IOS version.

Read more: What is IPsec?

Different Cisco Switches supports StackWise?

Catalyst 3750 Series

• 3750 / 3750G / 3750-E / 3750-X
• These were the first switches to introduce StackWise Technology.
• Use StackWise or StackWise Plus depending on the model.
• Max 9 switches in a stack.

Catalyst 3850 Series

• Supports StackWise-480
• Up to 9 switches in a stack.
• 480Gbps stack bandwidth.
• Supports IP routing, Layer 3, and wireless controller features.

Catalyst 9300 Series

• Supports StackWise-480 or StackWise-320 (depending on the model).
• Most current and widely used access switches in enterprise networks.
• Stack up to 8 switches.
• Also supports StackPower for power redundancy.

Catalyst 9200 Series

• Supports StackWise-160 or StackWise-80 (for lower-end models).
• Mid-level access switches.
• Stack up to 8 switches.
• Good for campus access layer.

Catalyst 2960-X Series

• Supports FlexStack or FlexStack-Plus (similar to StackWise).
• Up to 4 switches in a stack.
• More limited compared to higher-end models.

Catalyst 4500 and 6500 Series

• These are modular chassis switches and do not use StackWise Technology, but they use VSS (Virtual Switching System) instead a similar concept for chassis switches. You can order different types of Cisco Switch in Ateech.ae.

StackWise in Cisco Business Switches (CBS)?

Actually, traditional StackWise technology as found in Catalyst switches is generally NOT supported on Cisco Business (CBS) switches. Instead, Cisco Business switches use different stacking or management methods depending on the model.

• FlexStack (or FlexStack-Extended):
  Some Cisco Business switches (like the CBS 350 series) support FlexStack technology, which is similar to StackWise but designed for smaller SMB deployments. It allows stacking of up to 4 switches using stacking modules or cables.
• StackWise-like functionality:
  Higher-end Cisco Business switches (like CBS 450 or CBS 550 series) may support FlexStack Plus or StackPower, but not the full StackWise or StackWise Virtual technology that you find in Catalyst 9000 series.
• Web-based or Cloud management:
  Many CBS switches support centralized management via Cisco Business Dashboard, Cisco DNA Center, or Cisco Meraki Dashboard (if Meraki model), which helps simplify configuration but is different from true hardware stacking.

What Is StackWise Virtual?

StackWise Virtual is a Cisco technology that allows two separate switches to operate as a single logical switch, similar to traditional StackWise, but without requiring physical stack cables. Instead, the switches are connected using high-speed Ethernet links (like 10G, 40G, or 100G), usually via uplink or network modules.

It’s mainly used for core or distribution layer switches where stacking with physical cables is not practical due to distance or rack separation.

How does Stack Virtual work?

To set up StackWise Virtual, you use two compatible Cisco switches, such as two Catalyst 9500s. These switches are connected using Virtual Stack Links (VSL), which are high-bandwidth Ethernet connections (like 10G or 40G). Once connected, the switches synchronize their control planes, forwarding tables, and configurations.

One of the switches takes the role of the active (control plane master), while the other becomes standby. However, unlike traditional active-standby systems, both switches continue to forward traffic simultaneously.

From the network’s point of view, the two switches function as a single logical switch you manage them with one configuration and one IP address, and you can even create EtherChannels (port bundles) that span both physical devices.

Read more: Comparing Managed and Unmanaged Switches

StackWise VS StackWise Virtual:

Traditional StackWise and StackWise Virtual serve similar purposes but are designed for different environments and use cases. Traditional StackWise allows stacking of up to 8 or 9 switches, using special stack cables that require the switches to be placed very close together, usually within the same rack. This setup is typically used in the access layer of a network, where many switches are needed in one location.

On the other hand, StackWise Virtual supports only two switches, but it does not require stack cables and allows the devices to be physically separated, even across different racks or rooms. It is ideal for the core or distribution layer, where switches often need to be placed in different physical locations.

A major advantage of StackWise Virtual is that it supports Multi-chassis EtherChannel (MEC), allowing PortChannels to span both switches, something that’s not possible with separate switches in traditional setups unless they’re stacked.

Configuration of StackWise step by step:

Totally, you are using compatible switches such as 3850, 9300 and etc. stack cables are physically connected between stack ports on each switch and then switches are powered off before cabling.

Step 1: Connect the Stack Cables

• Use the StackWise ports (usually on the back).
• Connect in a ring topology (last switch connects back to the first one).
• For example:
  Switch 1 → Switch 2 → Switch 3 → back to Switch 1.

Step 2: Power On the Switches

• Power on one switch at a time in the desired order (usually the master first).
• The switch with the highest priority becomes the Stack Master.

Step 3: (Optional) Set Switch Priority

• To manually control which switch becomes the master:

Switch(config)# switch 1 priority 15

Switch(config)# switch 2 priority 10

Switch(config)# switch 3 priority 5

• Priority range: 1 (lowest) to 15 (highest)
• After reboot, the highest priority switch will become master.

Step 4: (Optional) Assign Switch Numbers

• If you want to assign or change stack member numbers:

Switch(config)# switch 1 renumber 3

Switch(config)# switch 2 renumber 1

Switch(config)# switch 3 renumber 2

This change takes effect after a reload:

Switch# reload

Step 5: Verify Stack Configuration

Use the following command to check stack status:

Switch# show switch

Switch#  Role    Mac Address     Priority  State

————————————————–

1        Active  000f.abcdef01         15        Ready

2        Member  000f.abcdef02    10        Ready

3        Member  000f.abcdef03     5         Ready

This shows which switch is active (master) and the roles of the others

Step 6: Configure Normally (Single IP & Config)

Now that the stack acts like a single switch:

• You configure it just like one device.
• Interfaces will be numbered like Gig1/0/1, Gig2/0/1, Gig3/0/1 (where 1, 2, 3 are the switch numbers).

Optional: Save Configuration

Switch# write memory

What is StackWise Plus?

StackWise Plus is an enhanced version of Cisco’s original StackWise technology, introduced with the Catalyst 3750-E and 3750-X series switches. It builds on the original concept of stacking multiple switches into a single logical unit but provides higher stack bandwidth and better performance.

It was developed to meet growing network demands for higher throughput and scalability without sacrificing the ease of management that stacking provides. The doubled bandwidth helps reduce potential bottlenecks between stack members, especially in larger or busier networks.

StackWise VS StackWise Plus:

Both technologies are Cisco’s solutions for stacking multiple switches, but StackWise Plus is an improved version of the original StackWise with enhanced features, especially in terms of bandwidth and performance.

• StackWise provides a 32Gbps full-duplex stack bandwidth, which was good for basic enterprise needs.
• StackWise Plus doubles this to 64Gbps full-duplex, which means faster communication between switches in the stack, reducing bottlenecks and improving overall throughput.
• StackWise Plus also supports some enhanced features like better redundancy and faster failover.
• Both use a ring topology, so if one link or switch fails, traffic is rerouted.

Conclusion:

Cisco StackWise Technology is a powerful and flexible stacking technology that allows multiple physical switches to operate as a single logical unit. Originally developed for the Catalyst 3750 series, it evolved into versions like StackWise Plus, StackWise-160, StackWise-480, and StackWise Virtual to meet the needs of different network layers from access to core.

This technology simplifies network management, improves redundancy and boosts bandwidth between switches by enabling fast interconnects and centralized control. Traditional StackWise uses physical stack cables and supports up to 9 switches, while StackWise Virtual uses high-speed Ethernet links to logically combine two high-end switches across longer distances, ideal for core and distribution layers.

Although Cisco Business Switches (CBS) don’t support StackWise itself, they offer simpler alternatives like FlexStack or cloud-based management, designed for smaller environments.

In summary, StackWise enhances scalability, simplifies configuration, and increases resiliency, making it an essential technology in modern enterprise networks especially when high availability and ease of management are key.