One unit of HUB to be connected in NIC switching mode is sufficient, but communication may not be conducted normally if the HUB has MAC learning capabilities. In such a case, add a HUB to make a HUB-to-HUB connection and then connect the cable to each HUB (See "Figure 2.12 System configuration in NIC switching mode" of "2.1.3 NIC switching mode").
It is not possible to use a standby patrol function when the type of interface to use is "mpnetX (a logical interface of a multipath)".
Communication with a multicast IP address is executed using a physical interface (normally, hme0) corresponding to a node name (uname -n). When used this interface in NIC switching mode, it is not possible to communicate with a multicast IP address. This occasionally outputs a following WARNING message from in.rdisc when activated a system:
in.rdiscd[xxx]: setsockopt(IP_DROP_MEMBERSHIP): Cannot assign requested address
In this case, either to set /etc/defaultrouter not to activate in.rdisc or reassign a node name to another interface.
In a standby patrol function of NIC switching mode, a dedicated Ethernet frame is used. Therefore, when operating VLAN (Virtual LAN), occasionally it is not possible to use a standby patrol function depending on the setting of VLAN. In such a case, either to stop a standby patrol function or VLAN, or change the setting of VLAN so that it becomes possible to use an optional Ethernet frame.
In NIC switching mode, it is necessary to use a hub that can be assigned an IP address in order for the hub to be monitored. If a hub cannot be assigned an IP address, an IP address of a device connected to the hub can be monitored. However, it should be noted that if the device whose IP address is monitored fails, the failure is regarded as a transfer route failure.
When using an IPv6 virtual interface, create an /etc/hostname6.interface file corresponding to a Primary physical interface so that an in.ndpd daemon is activated at activating a system. When the in.ndpd daemon is not activated, an IPv6 address is not configured automatically. When creating a /etc/hostname6.interface file, make it empty without fail.
When using an IPv6 virtual interface, an in.ndpd daemon is occasionally reactivated not to delay configuring an IPv6 address automatically. A message "SIGHUP: restart and reread config file" is output from the in.ndpd daemon following this, but this is not an error.
