HP procurve 8100fl series Management And Configuration Manual page 243

If a Backup router doesn't receive a keep-alive advertisement from the
■
current Master within a certain period of time, it will transition to the
Master state and start sending advertisements itself. The amount of time
that a Backup router will wait before it becomes the new Master is based
on the following equation:
Master-down-interval = (3 * advertisement-interval) + skew-time
The skew-time depends on the Backup router's configured priority:
Skew-time = ( (256 - Priority) / 256)
Therefore, the higher the priority, the faster a Backup router will
detect that the Master is down. For example:
– Default advertisement-interval = 1 second
– Default Backup router priority = 100
– Master-down-interval = time it takes a Backup to detect the
Master is down
= (3 * adv-interval) + skew-time
= (3 * 1 second) + ((256 - 100) / 256)
= 3.6 seconds
If a Master router is manually rebooted, or if its interface is manually
■
brought down, it will send a special keep-alive advertisement that lets the
Backup routers know that a new Master is needed immediately.
■ A virtual router will respond to ARP requests with a virtual MAC address.
This virtual MAC depends on the virtual router ID:
virtual MAC address = 00005E:0001xy
where xy is the virtual router ID (in hexadecimal format)
This virtual MAC address is also used as the source MAC address of
the keep-alive Advertisements transmitted by the Master router.
■ As specified in RFC 2338, a Backup router that has transitioned to Master
will not respond to pings, accept Telnet sessions, or field SNMP requests
directed at the virtual router's IP address.
By not responding the Backup router allows network management to
notice that the original Master router (that is, the IP address owner) is
down.
VRRP Configuration
Configuration Parameters
16-5