Dell PowerConnect B-FCXs, Configuration Manual

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1120 PowerConnect B-Series FCX Configuration Guide
53-1002266-01
Configuring additional VRRP and VRRPE parameters
31
Syntax: non-preempt-mode
The syntax is the same for VRRP and VRRPE.
Changing the timer scale
To achieve sub-second failover times, you can shorten the duration of all scale timers for VSRP,
VRRP, and VRRP-E by adjusting the timer scale. The timer scale is a value used by the software to
calculate the timers. By default, the scale value is 1. If you increase the timer scale, each timer’s
value is divided by the scale value. Using the timer scale to adjust timer values enables you to
easily change all the timers while preserving the ratios among their values. Here is an example.
If you configure the device to receive its timer values from the Master, the Backup also receives the
timer scale value from the Master.
NOTE
The Backups always use the value of the timer scale received from the Master, regardless of whether
the timer values that are saved in the configuration are the values configured on the Backup or the
values received from the Master.
To change the timer scale, enter a command such as the following at the global CONFIG level of the
CLI.
PowerConnect (config)# scale-timer 2
This command changes the scale to 2. All VSRP, VRRP, and VRRP-E timer values will be divided by
2.
Syntax: [no] scale-timer <num>
The <num> parameter specifies the multiplier. You can specify a timer scale from 1 – 10.
VRRP-E slow start timer
In a VRRP-E configuration, if a Master router goes down, the Backup router with the highest priority
takes over. When the Master comes back up again, it takes over from the Backup. By default, this
transition from Backup back to Master takes place immediately. However, you can configure the
VRRP-E slow start timer feature, which causes a specified amount of time to elapse between the
time the Master is restored and when it takes over from the Backup. This interval allows time for
OSPF convergence when the Master is restored.
Timer Timer scale Timer value
Hello interval 1 1 second
2 0.5 seconds
Dead interval 1 3 seconds
2 1.5 seconds
Backup Hello interval 1 60 seconds
2 30 seconds
Hold-down interval 1 2 seconds
2 1 second