Delivering multicast data traffic over a communication network includes a first network node delivering multicast data traffic to second network nodes. The first and second network nodes are connected by a transmission network in a ring architecture and implement a point-to-multipoint layer 2 protocol. A method includes at the first network node: collecting alarms signals indicative of a failure along the whole ring and of the second network nodes. Based on a current state of the alarm signals, delivering the multicast data traffic either in a first delivery direction along the ring, or in a second delivery direction along the ring opposite to the first delivery direction, or in both the first and second delivery directions. At each of the second network nodes: collecting alarm signals indicative of a failure of the transmission network locally to the second network node and of the second network node. Based on a current state of the local alarm signals either receiving the multicast data traffic delivered by the first network node from the first direction, forwarding the multicast data traffic in the first direction and transmitting local data traffic to the first network node along the second delivery direction, or receiving the data traffic delivered by the first network node from the second direction, forwarding the multicast data traffic in the second direction and transmitting the local data traffic to the first network node along the first delivery direction.