Hi Folks,
EX-series switches support all three flavors of the Spanning Tree Protocol: 802.1D (STP); 802.1s (Rapid Spanning Tree Protocol, or RSTP); and 802.1w (Multiple Spanning Tree Protocol, or MSTP).
RSTP is enabled on the EX-series switches by default. Spanning Tree is configured under the protocol stanza.
Check the Spanning Tree configuration
Basic Spanning Tree information, such as that shown below, can be obtained by entering the following command:
‘show spanning-tree bridge’
Determine who is blocking
Based on the established topology, there is a loop in the network. If Spanning Tree is working correctly, one of the links should be blocking. To check for port state (forwarding or blocking), enter the following command:
‘show spanning-tree interface’.
Next, enter the command ‘show spanning-tree interface’ to produce the following information:
- Port cost (the cost to use this link)
- State (port forwarding or blocking)
- Role (port roles are Designated [forwarding], Root [forwarding], Backup [blocking], Alternate [blocking], Edge [forwarding], and Disable [blocking])