Netgear XCM8806 - 8800 SERIES 6-SLOT CHASSIS SWITCH ユーザーズマニュアル

For complete information about software licensing, including how to 

obtain and upgrade your license and what licenses are appropriate 
for these features, see 

VRRP Master Election

When a VRRP configured network starts, VRRP uses an election algorithm to dynamically 
assign master responsibility to one of the VRRP routers on the network. The VRRP master is 
determined by the following factors:

VRRP priority—This is a user-defined field. The range of the priority value is 1 to 254; a 

higher number has higher priority. The value of 255 is reserved for a router that is 
configured with the virtual router IP address. A value of 0 is reserved for the master 
router, to indicate it is releasing responsibility for the virtual router. The default value is 
100.

Higher IP address—If the routers have the same configured priority, the router with the 

higher IP address becomes the master.

If the master router becomes unavailable, the election process provides dynamic failover and 
the backup router that has the highest priority assumes the role of master. 

A new master is elected when one of the following things happen: 

VRRP is disabled on the master router.

Loss of communication occurs between master and backup routers.

If VRRP is disabled on the master interface, the master router sends an advertisement with 
the priority set to 0 to all backup routers. This signals the backup routers that they do not 
need to wait for the master down interval to expire, and the master election process for a new 
master can begin immediately.

The master down interval is set using the following formula: 3 * advertisement interval + skew 
time.

Where:

The advertisement interval is a user-configurable option.

The skew time is (256-priority/256).

An extremely busy CPU can create a short dual master situation. To 

avoid this, increase the advertisement interval.