Dell PowerSwitch S4820T 9.50.1 Configuration Guide for the S4820T System - Page 793

The range is from 50 to 950 milliseconds. 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. Rapid Spanning Tree Protocol (RSTP) 793