How to Configure RSTP (802.1w) and Implement Spanning Tree Best Practices on ICX Switches

Hello everyone,

Today, I'd like to delve into configuring Rapid Spanning Tree Protocol (RSTP) on ICX switches and share some best practices. By default, ICX switches operate using the standard 802.1d Spanning Tree Protocol (STP) on a per-VLAN basis. However, for faster network convergence, it's advantageous to switch to RSTP (802.1w). I'll guide you through general configuration steps and highlight some key practices that serve as a solid foundation for many network setups. While these configurations might not fit every scenario perfectly, they're a great starting point.

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Enabling RSTP on VLANs

First, we'll enable RSTP on your desired VLANs. You can configure multiple VLANs simultaneously or handle them individually. Here's how to enable RSTP on VLANs 10, 20, and 30:

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Setting the Root Bridge Priority

Next, it's essential to set the root bridge priority. If you don't specify a priority, the switch uses the default value of 32768. To ensure your switch becomes the root bridge, assign it a lower priority number. Setting the priority to zero guarantees that this switch will be the root:

 

Your configuration should now resemble:

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Optimizing Switch-to-Switch Links

For optimal convergence times, define switch-to-switch connections as point-to-point links. Assuming ports 1/2/1 through 1/2/8 are your inter-switch links, configure them like this:

 

This updates your configuration to include:

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Configuring Edge Ports

For ports connected to end devices (edge ports), define them as operational edge ports to expedite the transition to the forwarding state. If ports 1/1/1 through 1/1/48 are your edge ports, use the following commands:

You can also enable STP BPDU Guard on these ports to protect against accidental loops by shutting down the port if a BPDU is received:

 

This results in:

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Monitoring RSTP Status

To view RSTP information, use the following commands:

Note: If you're using the standard 802.1d STP, the commands are show spanning-tree and show spanning-tree detail. For Multiple Spanning Tree Protocol (MSTP), use show mstp and show mstp detail.

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For a comprehensive list of configuration options and further details, refer to the FastIron Layer 2 Switching Configuration Guide.