28.2.2 Control VLAN

In a network using the Ring Protocol, a special VLAN for sending and receiving control frames is used to restrict the range for sending control frames. These VLANs are called control VLANs, and the same VLAN is used for all nodes constituting a ring. Because control VLANs use a single common VLAN for each ring, in a multi-ring configuration, different VLANs need to be used in neighboring rings.