How to Stack Cisco 9300 Switches for Network Scalability and Resiliency
Selene Gong
For small to medium-sized enterprises (SMEs) navigating the complexities of modern network infrastructure, optimizing performance, ensuring high availability, and simplifying management are paramount. When considering network switches, questions often arise: How can we scale our access layer efficiently? How do we provide robust redundancy without overcomplicating our setup? Cisco 9300 stacking emerges as a powerful solution, transforming multiple physical switches into a single, cohesive logical unit.
What is Cisco 9300 Stacking?
Cisco 9300 stacking leverages Cisco's innovative StackWise technology to combine up to eight individual Cisco Catalyst 9300 Series Switches into a single, virtual switch. This approach offers a unified control plane and management plane, significantly simplifying network operations and enhancing overall system resilience. Instead of managing each switch individually, IT administrators can configure and monitor the entire stack as one logical entity, whether on-premises, virtually, or from the cloud. This also means that Layer 2 and Layer 3 protocols present the entire switch stack as a single entity to the network.
Types of Cisco 9300 Stacking: Bandwidth and Compatibility
The Cisco Catalyst 9300 Series offers flexible stacking options tailored to various performance needs:
StackWise-1T: Available exclusively on Cisco Catalyst 9300X models, this provides up to 1 Tbps of stacking bandwidth. It is the industry’s highest-density stacking bandwidth solution with a flexible uplink architecture, supporting 100G, 40G, 25G, Multigigabit, 10G, and 1G modular uplinks.
StackWise-480: Supported by Cisco Catalyst 9300 modular uplink models, offering a robust 480 Gbps of stacking bandwidth.
StackWise-320: Found on Cisco Catalyst 9300L and 9300LM fixed uplink models, providing 320 Gbps of stacking bandwidth.
Mixed Stacking with Cisco 9300
Cisco 9300 stacking supports mixed configurations. You can stack Catalyst 9300X models with Catalyst 9300 modular uplink models, although the stack will operate at the lower StackWise-480 speed. However, it's important to note that fixed uplink models (C9300L SKUs) cannot be stacked with modular uplink models (C9300/C9300X SKUs) or other Catalyst switches like the 3850 and 3650 Series. Additionally, some higher-scale C9300 models (C9300-24UB, C9300-24UXB, C9300-48UB) can only be stacked with each other. It's also crucial that all switches in the stack run the same license level and compatible software versions to ensure proper operation.
How to Stack Cisco 9300 Switches: A Basic Guide
Power Off: Ensure all switches are powered off before connecting any cables to prevent unintended stack merges or splits.
Connect Stack Cables: Each switch has dedicated stack ports on its rear panel. For StackWise-1T/480, directly connect the proprietary Cisco StackWise cables (available in 0.5m, 1m, 3m lengths). For StackWise-320 (C9300L/LM models), you'll need a Stack Kit (e.g., C9300L-STACK-KIT), which includes two stack adapters and a stacking cable. Cabling typically forms a ring topology for redundancy and full bandwidth. A common switch stack diagram involves connecting the bottom stack port of one switch to the top stack port of the next switch in a daisy-chain fashion, and then looping back the last switch's bottom port to the first switch's top port to complete the ring. Ensure the cable is properly connected to avoid errors.
Power On: Power on the switches. The switches will automatically elect an active switch (master) and a standby switch. You can influence this election by assigning a higher priority value (1-15, default is 1) to your preferred active switch, or by powering it on first. If you have no preference, power on all switches within 1 minute for them to participate in the election.
Verification and Configuration: After power-on, connect a console cable to the active switch. Use the show switch command to verify stack members, their roles (active, standby, member), and priorities.
show switch stack-ring speed and show switch stack-bandwidth provide details on the current and next-boot stacking speeds.
show interface status can confirm all ports across the stack are visible and operational as if from a single device.
To manually configure higher speeds on homogeneous 9300X stacks, use the global configuration command switch stack-speed high. This requires a reload for the change to take effect.
Stacking Priority Setting: Complete CLI Example
For deterministic system role election, it is recommended to adjust the switch priority for all stack switches. The switch with a higher priority (15 is the highest, 1 is default) becomes the active switch. This configuration needs to be done from EXEC mode and requires a reload for the change to take effect.
Device# enable
Device# configure terminal
Device(config)# switch 1 priority 15 ! Set priority 15 for switch 1 (preferred active)
Device(config)# switch 2 priority 10 ! Set priority 10 for switch 2 (preferred standby)
Device(config)# switch 3 priority 5 ! Set priority 5 for switch 3 (member)
Device(config)# end
Device# reload ! A reload is required for the new priority to take effect and influence election
After reloading, you can verify the new priorities and roles using show switch. Manually setting the priority helps ensure that your preferred switch is elected as the active switch if a reelection occurs.
Key Benefits of Cisco 9300 Stacking for SMEs
Simplified Management: Manage up to eight physical switches as a single logical unit, streamlining configuration, monitoring, and troubleshooting. This significantly reduces operational overhead and IT staff workload.
Enhanced Scalability: Easily expand network capacity by adding more switches to the stack, allowing for a 'pay-as-you-grow' model. The high-density port offerings, including Multigigabit and UPOE+, support growing IoT and high-bandwidth wireless demands.
High Availability and Resiliency: With an active and standby switch, the stack provides Nonstop Forwarding (NSF) and Stateful Switchover (SSO), ensuring sub-50ms failover in case of an active switch failure. Cross-stack EtherChannel allows for robust uplink redundancy and load balancing across stack members.
Cost Efficiency: Consolidating management reduces operational expenses (OpEx). Additionally, features like Cisco StackPower (supported on 9300 and 9300X models) enable power sharing and redundancy across the stack, optimizing power infrastructure and providing higher power budgets for devices.
Consistent Policy Enforcement: A single policy plane for wired and wireless networks simplifies security (e.g., MACsec encryption, Encrypted Traffic Analytics) and Quality of Service (QoS) enforcement across the access layer.
Application Scenarios & Selection Advice
When selecting the right Cisco 9300 stacking solution for your SME, consider your current and future network demands:
High-Bandwidth Environments (e.g., Wi-Fi 6/6E deployments, heavy video traffic, large number of IoT devices): Cisco Catalyst 9300X models with StackWise-1T are ideal. They offer the highest stacking bandwidth and density, supporting extensive Multigigabit and 90W UPOE+ ports.
Standard Enterprise Access (general wired/wireless connectivity, branch offices): Cisco Catalyst 9300 models with StackWise-480 provide excellent performance and features for most access layer needs, offering a balance of capacity and cost.
Cost-Optimized Deployments (smaller offices, less demanding access, basic connectivity): Cisco Catalyst 9300L/LM models with StackWise-320 offer a more economical entry point while still providing robust stacking benefits for simpler network requirements.
Remember that for optimal performance, ensuring all switches in the stack run compatible software versions and have the same license level is crucial. Cisco's Smart Licensing simplifies this process, allowing for flexible license management across your organization.
Common FAQs about Cisco 9300 Stacking
Q: Can I add switches to a live stack?
A: Yes, but it is recommended to power off the new switch before connecting stack cables to avoid a stack merge that triggers a reload. If needed, enable software auto-upgrade on the active switch to automatically align software versions when adding new members.
Q: What happens if the active switch fails?
A: The standby switch automatically takes over using Nonstop Forwarding (NSF) and Stateful Switchover (SSO), ensuring fast failover with minimal disruption. The previous active switch becomes a member when it rejoins.
Q: Can I stack switches with different licenses?
A: No. All switches in the stack must use the same license level. A mismatch prevents the new switch from fully joining the stack. For IOS XE 16.9.1+, Smart Licensing may auto-enable an evaluation license; otherwise, manual activation is needed.
Q: How do I upgrade IOS XE in a stack?
A: Enable software auto-upgrade on the active switch so new switches auto-align their software. For upgrading the entire stack, Cisco 9300 supports Extended Fast Software Upgrade (xFSU) for minimal downtime (under 30 seconds) during upgrades.
Q: How many switches can I stack?
A: Up to eight Cisco 9300 switches can be stacked in a ring topology, providing up to 448 access ports in a single logical unit.
Explore our range of Cisco Catalyst 9300 Switches and Stacking Cables to enhance your network infrastructure. For more detailed configuration guides or specific product inquiries, our experts are ready to assist you.
