HP 3500YL - Manual (Page 362)

Virtual Router Redundancy Protocol (VRRP)
Using the Pre-empt Delay Timer
Syntax: [no] preempt-delay-time <1-600 >
Allows you to specify a time in seconds that this router will
wait before taking control of the virtual IP address and
beginning to route packets. You can configure the timer on
VRRP Owner and Backup routers.
Note: If you have configured the Preempt Delay Timer with a
non-zero value, you must use the
no form of the command to
change it to 0 (zero).
Default: 0 (zero) seconds.
N o t e The value of the PDT cannot be changed when the VR is active. This is in
accordance with other VR parameters (such as advertisement interval,
priority, virtual IP address, mode, and so forth) that cannot be changed when
the VR is active.
VRRP Preempt Mode with LACP and Older ProCurve Devices
There can be an issue with VRRP Preempt Mode if an older ProCurve device
(2524, 2650, 2848, 3400, or 5300) is the intermediate device connecting to a
VRRP router and has LACP set in “enable, passive” mode. This mode is set by
default on older ProCurve devices, whereas it is disabled by default on later
models such as the ProCurve Series 5400zl. ProCurve recommends that you
use compatible LACP settings on devices that connect with VRRP routers on
VRRP VLANs.
What Occurs at Startup
When the Owner router comes online, it will wait for the configured amount
of time before taking control of the virtual IP address. This period of time is
calculated as follows:
If the value of the Master down time (3 * advertisement interval) is less than or
equal to the preempt delay time, then the Owner router will wait until the Master
down time (3 * advertisement interval) has expired.
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