3Com 5500G, 4210, 4200G manual Vlan Interface

72CHAPTER 13: AUTO DETECT CONFIGURATION GUIDE

Auto Detect	You can implement VLAN interface backup through auto detect. When data can
Implementation in	be transmitted through two VLAN interfaces on the switch to the same
VLAN Interface	destination, configure one of the VLAN interfaces as the active interface and the
Backup	other as the standby interface. Through the auto detect function, the standby
	interface is enabled automatically when the active fails, so as to ensure the data
	transmission:
	■ In normal situations (that is, when the detected group is reachable), the
	standby VLAN interface is down and packets are sent to the destination
	through the active VLAN interface.
	■ When the communication between the active VLAN interface and the
	destination fails (that is, the detected group is unreachable), the system
	enables the backup VLAN interface.
	■ When the communication between the active VLAN interface and the
	destination resumes, the system shuts down the standby VLAN interface again.
Network Diagram	Figure 21 Network diagram of applying auto detect to VLAN interface backup
			Vlan- int1		Vlan- int2
		192.168.1.2 /24 Switch B 10.1.1 .3/24
		Vlan-int1			Vlan -int2
		192.168.1.1/24			10 .1.1.4/24
				Vlan-int2	Vlan- int1
	Host A	Switch A		192.168.3.1/24	10.1.2.1/24	Host C
					Switch C
			Vlan-int2		Vlan-int1
		192.168.3.2 /24			10.1.2 .2/24

Switch D

Networking and

Configuration

Requirements

■Make sure that there is a route between Switch A and Switch B, Switch B and Switch C, Switch A and Switch D, and Switch D and Switch C.

■Create detected group 10 on Switch A to detect the connectivity between Switch A and Switch C.

■Configure VLAN-interface 1 to be the active interface, which is enabled when the detected group 10 is reachable.

■Configure VLAN-interface 2 to be the standby interface, which is enabled when the detected group 10 is unreachable.

■Create detected group 9 on Switch C to detect the connectivity between Switch C and Switch A.

■Configure VLAN-interface 2 to be the active interface, which is enabled when the detected group 9 is reachable.

■Configure VLAN-interface 1 to be the standby interface, which is enabled when the detected group 9 is unreachable.