To reduce the amount of traffic sent over the ISL between Switch-1 and Switch-2, enable Equal Cost Multi Path (ECMP) on both Switch-1 and Switch-2 is not a correct explanation of how to control how core-to-access traffic is forwarded. Switch-1, Switch-2, and the router run OSPF on LAG 100, which is a Layer 3 LAG. ECMP is a feature that allows a router to load balance traffic destined to some network that is reachable through multiple equal cost route nexthops. Enabling ECMP on Switch-1 and Switch-2 would not reduce the amount of traffic sent over the ISL, but rather increase it by sending traffic over both links instead of one. A better way to reduce the amount of traffic sent over the ISL would be to enable active forwarding on LAG 100 on both Switch-1 and Switch-2, which would make one link active and one link standby for each direction of traffic1.

The status is Protection, which means that the ring is up and fully connected with the RPL port blocked is what the specified status means for Ethernet Ring Protection Switching (ERPS) on an ArubaOS-CX switch. Protection is one of the possible statuses for an ERPS ring instance, and it indicates that the ring is operating normally with one port blocked to prevent loops. The RPL port is the port that connects to the RPL node, which is responsible for blocking and unblocking traffic on the ring.