Reference Guide

Example of Verifying Hello-Time Interval
Dell(conf-rstp)#do show spanning-tree rstp brief
Executing IEEE compatible Spanning Tree Protocol
Root ID Priority 0, Address 0001.e811.2233
Root Bridge hello time 50 ms, max age 20, forward delay 15
Bridge ID Priority 0, Address 0001.e811.2233
We are the root
Configured hello time 50 ms, max age 20, forward delay 15
NOTE: The hello time is encoded in BPDUs in increments of 1/256ths of a second. The standard
minimum hello time in seconds is 1 second, which is encoded as 256. Millisecond. hello times are
encoded using values less than 256; the millisecond hello time equals (x/1000)*256. When you
configure millisecond hellos, the default hello interval of 2 seconds is still used for edge ports; the
millisecond hello interval is not used.
Flush MAC Addresses after a Topology Change
Dell Networking OS has an optimized MAC address flush mechanism for RSTP, MSTP, and PVST+ that
flushes addresses only when necessary, which allows for faster convergence during topology changes.
However, you may activate the flushing mechanism defined by 802.1Q-2003 using the tc-flush-
standard
command, which flushes MAC addresses after every topology change notification.
To view the enable status of this feature, use the show running-config spanning-tree mstp
command from EXEC Privilege mode.
MSTP Sample Configurations
The running-configurations support the topology shown in the following illustration.
The configurations are from SFTOS systems.
Figure 95. MSTP with Three VLANs Mapped to Two Spanning Tree Instances
622
Multiple Spanning Tree Protocol (MSTP)