void __4_5_1__DEVICE_LEVEL_RING_DLR() {
    /**
     * @group:       	4.5.1 DEVICE LEVEL RING (DLR)
     *
     * @description:	DLR is a redundancy protocol defined for EtherNet/IP industrial networks by Open DeviceNet Vendor Association
     * 					(ODVA). It calls for a ring topology consisting of a supervisor node and a number of ring nodes. Backup (inactive) super-
     * 					visors are also permitted.
     * 					To prevent frames from circulating endlessly around the ring, the supervisor blocks one of its ports (except for special
     * 					protocol frames). To monitor the health of the network, the supervisor periodically transmits duplicate Beacon frames
     * 					out both of its ring ports. The Beacon frame pairs then traverse the ring in opposite directions and arrive back at the
     * 					supervisor. The supervisor (and any of the other ring nodes) can detect a ring failure by watching received Beacon
     * 					frames and monitoring the absence of a frame. When a network failure occurs, all nodes flush their Ethernet forwarding
     * 					tables, and the supervisor unblocks its blocked port. To minimize the switchover time, it is critical that failure detection
     * 					and response occur very quickly.
     * 					The KSZ9477S provides the following hardware support for the implementation of a DLR network:
     * 					• Automatic generation of Beacon frames (supervisor node)
     * 					• Beacon timeout detection (all nodes)
     * 					• Port blocking (supervisor node)
     * 					• Instant flush of forwarding tables (all nodes)
     * 					Any two ports of the KSZ9477S may be used as the ports for participation in the DLR ring. These ports are selected by
     * 					setting two bits, as appropriate, in the DLR Port Map register.
     * 					The main feature to help off-load the host processor in the supervisor node is the Beacon frame generator. This is
     * 					enabled by setting bit 1 in the Global DLR Control register (0x0610). All of the fields of the Beacon frame are program-
     * 					mable, using registers 0x0608 to 0x0627. These include source IP address, node state, ring state, supervisor prece-
     * 					dence, beacon interval and beacon timeout interval. Even the destination MAC address is programmable, though the
     * 					value is specified by the standard. The Beacon interval, which defaults to 400 us, is programmable in the Global DLR
     * 					Beacon Interval register (0x0614-17).
     * 					Beacon timeout detection is performed by setting up the appropriate ACL rules.
     * 					To enable backup supervisor mode, set bit 2 in the Global DLR Control register (0x0610). When in this mode, the chip
     * 					will detect the loss of the active supervisor by detecting beacon timeout on both ports. For this mode, a Beacon timeout
     * 					window value is programmable in the Global DLR Beacon TO Window register (0x061C-1F). This window limits the time
     * 					between the beacon timeouts on the two ports. If the interval is greater than this limit, then the two timeouts do not qualify
     * 					as a legitimate loss of active supervisor.
     * 					Port blocking is achieved by clearing bits 1 and 2 in the Port MSTP State Register.
     * 					When a ring failure is detected or notification of such is received, each node in the ring must flush its dynamic MAC
     * 					address forwarding table. This is controlled via the Switch Lookup Engine Control 2 Register.
     *
     */
}