ERPS timers

Hold-off

The hold-off timer starts when the port detects a link fault.

The port reports the link fault if the fault persists when the timer expires.

This timer delays the fault report time and affects the link switching performance.

Guard

The guard timer starts when the port detects a link recovery.

The port does not process R-APS packets before the timer expires.

This timer prevents R-APS packets from impacting the network and affects the link switching performance when multiple points of failures exist.

WTR

In revertive mode, the WTR timer starts when the owner node in protection state receives NR packets.

The RPL is unblocked and the recovered node is blocked before the timer expires. The owner node blocks the RPL and sends NR-RB packets when the timer expires.

If the port receives SF packets before the timer expires, the timer stops and the RPL remains unblocked.

This timer prevents intermittent link failures from impacting the network.

WTB

In revertive mode, the WTB timer starts when the owner node in MS or FS state receives NR packets.

The RPL is unblocked and the recovered node sends NR packets before the timer expires. The owner node blocks the RPL and sends NR-RB packets when the timer expires.

If the port receives SF packets before the timer expires, the timer stops and the RPL remains unblocked.

This timer prevents the RPL ports from being blocked and unblocked frequently.