Fast Hellos For Link State Detection - Dell Force10 C150 Configuration Manual

Fast Hellos for Link State Detection

Fast Hellos for Link State Detection
Use RSTP Fast Hellos to achieve sub-second link-down detection so that convergence is triggered faster.
The standard RSTP link-state detection mechanism does not offer the same low link-state detection speed.
RSTP Fast Hellos decrease the hello interval to the order of milliseconds and all timers derived from the
hello timer are adjusted accordingly. This feature does not inter-operate with other vendors, and is
available only for RSTP.
Task
Configure a hello time on the order of milliseconds.
FTOS(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
Bridge ID
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.
Note: When millisecond hellos are configured, the default hello interval of 2 seconds is still used for edge
ports; the millisecond hello interval is not used.
is available only on platform:
50 ms, max age 20, forward delay 15
Priority 0, Address 0001.e811.2233
s
Command Syntax
hello-time milli-second interval
Range: 50 - 950 milliseconds
Command Mode
PROTOCOL RSTP
Rapid Spanning Tree Protocol | 909