MVID 03h - Claim Token - CL_TK
Destination Address: C0-00-FF-FF-FF-FF (ring multicast / 'this ring')
Destination Class: 0 (ring station)
Source Class: 0 (ring station)
Subvectors: SVID 0Bh - Physical Drop Number
If an active monitor stops operation, the next downstream ring station will miss its frames; then this downstream station will send 'claim token' MAC frames. If no other station claims to be active monitor, the error detecting station will take over the active monitor function. Other stations may claim to be active monitor if they are configured to join in the monitor contention process.
During monitor contention process, any station that is allowed to join the contention process will replace the 'claim token' frame's destination address by its own address under condition that its own MAC address has a higher value than the frame's destination address.
This causes that the adapter with the highest MAC address will become the next active monitor (mostly bridges).