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 2.7 System configuration in NIC switching mode of "2.1.2 NIC switching mode").
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 the system is RHEL, if you are using IPv6 virtual interface, you must set "NETWORKING_IPV6=yes" in the /etc/sysconfig/network file. By defining this configuration, the system loads ipv6 module during the system startup.
When using an IPv6 virtual interface, an radvd daemon is occasionally reactivated not to delay configuring an IPv6 address automatically. A message "radvd[XXXX]: resuming normal operation" is output from the radvd daemon following this, but this is not an error.
Do not configure the server running NIC switching mode as an IPv6 router.
