Nortel SMC 2450, Implementation Manual

Page: 179 / 262

Maintenance Page 179 of 260
Secure Multimedia Controller Implementation Guide
When the active master becomes the backup, it overwrites its virtual router
MAC address with its physical MAC address. At the same time, the newly
active master overwrites its physical MAC address with its unique virtual
router MAC address.
Note: In practice, GARP messaging is usually the mechanism that
informs switches and routers of MAC address changes.
VRRP router parameters
You can define VRRP router parameters globally using either the CLI or the
Web UI. You can use the following parameters to configure VRRP:
• Active-Standby
• Advertisement interval
• Gratuitous ARP (GARP)
• VRRP interface
• Advanced failover check
Active-Standby
The active-standby parameter enables Active-Standby, which is also referred
to as HA. You can apply Active-Standby only when there are two SMCs in
the cluster.
Advertisement interval
The advertisement interval parameter sets the interval in seconds between
advertisement messages, which are multicast to 224.0.0.18 from the active
master’s subaddress. See “VRRP interface” on
page 180 . If the backup does
not receive advertisement messages at the specified interval, the VRRP
failover process begins.
It may be necessary to increase the advertisement interval during high traffic
periods that prevent the active SMC from issuing advertisement messages at
the specified interval. Increasing the advertisement interval lowers the chance
for unnecessary disruption of packet forwarding, but increases the length of
service disruption in the event that the active master fails.