3Com 3500 manual Router Indexes, Backup Auto-learn

496CHAPTER 17: VIRTUAL ROUTER REDUNDANCY (VRRP)

Advertisement Intervals

■When you define a Primary router on a VLAN that contains a single interface, the single interface is automatically chosen as the primary address when you select IP-addressas the Address mode.

■When you define a Backup virtual router, selecting auto-learnas the address mode configures the Backup router to learn the IP addresses that are associated with the virtual router by means of VRRP advertisements from the Primary router. The Primary router must be up for backup routers to auto-learn the addresses that are associated with the specified VRID.

■When you define Backup virtual routers, the auto-learn address mode option enables auto address learning for the specified VRID. If a new interface is added to the VLAN on a primary virtual router, the new IP address is sent out in VRRP advertisements so that the Backup routers in auto-learn mode can learn the new address without having to manually add the new address to each backup router.

■The smaller the advertisement interval, the smaller the failover time if the master fails.

■The advertisement interval must be the same across the set of VRRP routers that are associated with a single VRID. Backup routers must have the same advertisement interval as the Master router.

Options

Prompt	Description	Possible Values	[Default]
VLAN	Index number of the	■ Index number of an IP	Index
interface	virtual LAN (VLAN) on	virtual LAN (VLAN) that is	number of
index	which you want to	defined on the system.	first available
	define the virtual	■ ? (for a list of selectable	VLAN
	router
		indexes)
VRID	Virtual router	1 – 255	1
	identifier. Identifies
	the virtual router that
	you want to define on
	the LAN.

Virtual	Type of virtual router
router type	that you want to
	define
Address	Method by which the
mode	virtual router you
	want to define learns
	its IP addresses

■ Primary Primary

■Backup

■ auto-learn auto-learn

■IP address