Configuring Fast Hellos For Link State Detection - Dell S4820T Configuration Manual

• If the interface to be shut down is a port channel, all the member ports are disabled in the hardware.
• When you add a physical port to a port channel already in the Error Disable state, the new member
port is also disabled in the hardware.
• When you remove a physical port from a port channel in the Error Disable state, the error disabled
state is cleared on this physical port (the physical port is enabled in the hardware).
• The reset linecard command does not clear the Error Disabled state of the port or the hardware
disabled state. The interface continues to be disables in the hardware.
• You can clear the Error Disabled state with any of the following methods:
– Perform an shutdown command on the interface.
– Disable the shutdown-on-violation command on the interface (the no spanning-tree
stp-id portfast [bpduguard | [shutdown-on-violation]] command).
– Disable spanning tree on the interface (the no spanning-tree command in INTERFACE mode).
– Disable global spanning tree (the no spanning-tree command in CONFIGURATION mode).
To enable EdgePort on an interface, use the following command.
• Enable EdgePort on an interface.
INTERFACE mode
spanning-tree rstp edge-port [bpduguard | shutdown-on-violation]
Example of Verifying an EdgePort is Enabled on an Interface
To verify that EdgePort is enabled on a port, use the show spanning-tree rstp command from EXEC
privilege mode or the show config command from INTERFACE mode.
NOTE: Dell Networking recommends using the show config command from INTERFACE mode.
In the following example, the bold line indicates that the interface is in EdgePort mode.
Dell(conf-if-te-2/1)#show config
!
interface TenGigabitEthernet 2/1
no ip address
switchport
spanning-tree rstp edge-port
shutdown
Dell(conf-if-te-2/1)#

Configuring Fast Hellos for Link State Detection

To achieve sub-second link-down detection so that convergence is triggered faster, use RSTP fast hellos.
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.
• Configure a hello time on the order of milliseconds.
PROTOCOL RSTP mode
hello-time milli-second interval
Rapid Spanning Tree Protocol (RSTP)
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