Quick Reference Guide

230 PowerConnect B-Series TI24X Configuration Guide
53-1002269-02
Virtual Switch Redundancy Protocol (VSRP)
8
Timer scale
The VSRP hello interval, dead interval, backup hello interval, and hold-down interval timers are
individually configurable. You also can easily change all the timers at the same time while
preserving the ratios among their values. To do so, change the timer scale. The timer scale is a
value used by the software to calculate the timers. The software divides a timer value by the timer
scale value. By default, the scale is 1. This means the VSRP timer values are the same as the
values in the configuration. For more information on timer scale parameters and how it affects the
timers, refer to Table 35.
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
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.
Table 1:
Timer Timer scale Timer value
Hello interval 1 1 second
20.5 seconds
Dead interval 1 3 seconds
21.5 seconds
Backup Hello interval 1 60 seconds
2 30 seconds
Hold-down interval 1 2 seconds
21 second