PRIMECLUSTER Global Link Services Configuration and Administration Guide: Redundant Line Control Function 4.2 (for Linux)

3.7.2.2 Operating tagged VLAN interface on NIC switching mode

When using a tagged VLAN interface on NIC switching mode, specify the tagged VLAN interface instead of a physical interface at configuration.

In addition, when tagged VLAN interfaces on the same physical network cable is made redundant by two or more virtual interfaces, the mode to "synchronous switching" or "asynchronous switching" operation is defined. Below, operation of "synchronous switching" and "asynchronous switching" is explained.

[Table 3.7 Synchronous switching and asynchronous switching]

Redundant network methods		Switchover
		Synchronous	Asynchronous
NIC switching mode (Logical IP takeover)	IPv4	Enabled	Enabled
	IPv6	Enabled	Enabled
	Dual	Enabled	Enabled
NIC switching mode (Physical IP takeover)	IPv4	Disabled	Enabled

For configuration of monitoring target, refer to "7.7 hanetpoll Command".

Synchronous switching

In two or more virtual interfaces which bundle multiple tagged VLAN interfaces redundantly, by defining the same monitoring target IP address, all virtual interfaces are synchronous switching, when failure occurs in monitoring of transfer path. When the switch/HUB of a monitoring target has only one IP address, "synchronous switching" of a virtual interface is chosen.

Figure 3.8 illustrates of synchronous switching architecture.

[Figure 3.8 NIC switching mode with tagged VLAN interface (synchronous switching)]

In the above figure, sha0 and sha1 of the network interfaces monitor the same IP address. If a transmission route failure is detected on sha0, virtual interface switching of sha1 as well as sha0 will occur,

Asynchronous switching

Two or more virtual interfaces that bundle the tagged VLAN interface can be asynchronously switched. In this case, the monitoring target IP address from which it differs for every virtual interface is defined as monitoring target information. When two or more definitions of the IP address are possible to switch/HUB used as a monitoring target, the asynchronous switching of the virtual interfaces is chosen to use Standby NIC effectively.

Figure 3.9 illustrates of asynchronous switching architecture.

[Figure 3.9 NIC switching mode with tagged VLAN interface (asynchronous switching)]

In the above figure, sha0 and sha1 of the network interfaces monitor the different IP addresses respectively. If a transmission route failure is detected on sha0, and virtual interface switching of sha0 occurs, that of sha1 will not occur.

• On NIC switching mode, if several tagged VLAN interfaces exist on two physical interfaces, and at lease two virtual interfaces are created on pairs of those tagged VLAN interfaces, please ensure that you configure the standby patrol function exclusively on a single virtual interface. For example, say virtual interface (sha0) is created on two tagged VLAN interfaces "eth0.1" and "eth1.1", and similarly, another virtual interface (sha1) is created on "eth1.2" and "eth0.2", the standby patrol function must be configured on either one of the virtual interfaces (sha0 or sha1).
• On NIC switching mode, tagged VLAN interfaces on a pair of physical interfaces should be used to create multiple virtual interfaces, if tagged VLAN networks are used. For example, you cannot have an environment where a virtual interface is created on a pair of VLAN interfaces "eth0.1" and "eth1.1", and another virtual interface is created on a pair of VLAN interfaces "eth1.2" and "eth2.2" because the physical interface "eth1" is the only shared physical interface here.
• If you specify two monitoring targets with synchronous switching mode, please specify two network addresses which belong to the same network. If their network addresses are different, switch/HUB monitoring cannot operate normally, because they are assigned to only one virtual interface.
• When the physical IP address takeover function of the NIC switching mode is used, a virtual interface cannot be synchronous switched.