Cabletron Systems SmartSwitch manual Vrrp Configuration Notes, Ip-redundancy show

Chapter 7: VRRP Configuration Guide

ip-redundancy show

The ip-redundancy show command reports information about a VRRP configuration. To display VRRP information, enter the following commands in Enable mode.

Display information about all	ip-redundancy show vrrp
virtual routers.
Display information about all	ip-redundancy show vrrp interface <interface>
virtual routers on a specified
interface.
Display detailed statistics about	ip-redundancy show vrrp <vrid> interface
a specific virtual router	<interface> verbose

VRRP Configuration Notes

•The Master router sends keep-alive advertisements. The frequency of these keep-alive advertisements is determined by setting the Advertisement interval parameter. The default value is 1 second.

•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.

106 SmartSwitch Router User Reference Manual