Protecting an ethernet network having a ring architecture

A hub network node adapted to deliver multicast data traffic over a communication network comprising the hub network node and at least two spoke network nodes and a transmission network connecting the hub and spoke network nodes in a ring architecture, and wherein the hub network node and the spoke network nodes implement a point-to-multipoint layer 2 protocol, the hub network node comprising a multicast traffic delivery protection function adapted to:

• collect alarm signals indicative of a failure condition of the transmission network along the whole ring and of the at least two spoke network nodes, and
• based on a current state of the alarm signals, cause the delivery of the multicast data traffic:
• in a first delivery direction along the ring when no fault is detected;
• in a second delivery direction along the ring opposite to the first delivery direction if the collected alarm signals indicate a failure condition of a first type, wherein the failure condition of the first type comprises at least one of:
• a failure of a network node directly connected to the first network node and a failure of a portion of the transmission network between the first network node and the network node directly connected to the first network node;
• and
• in both the first and second delivery directions along the ring if the collected alarm signals indicate a failure condition of a second type different from the first type, wherein the failure condition of the second type comprises at least one of:
• a failure of a network node not directly connected to the hub network node and a failure of a portion of the transmission network not directly connected to the hub network node.

A spoke network node adapted to receive multicast data traffic delivered by a hub network node connected to the spoke network by a transmission network in a ring architecture, and wherein the spoke network node implements a point-to-multipoint layer 2 protocol, the spoke network node comprising a multicast traffic delivery protection function adapted to:

• collect local alarm signals indicative of a failure condition of the transmission network locally to the spoke network node and of the spoke network node,
• transmit, to the hub network node, a message indicating the collected local alarm signals, wherein the message is configured to cause the hub network node to deliver the multicast data traffic in a second delivery direction if the message indicates a failure condition of a first type, wherein the failure condition of the first type comprises at least one of:
• a failure of a network node directly connected to the first network node and a failure of a portion of the transmission network between the first network node and the network node directly connected to the first network node;
• and to deliver the multicast data traffic in both the second direction and a first delivery direction along the ring opposite to the second delivery direction if the message indicates a failure condition of a second type different from the first type, wherein the failure condition of the second type comprises at least one of:
• a failure of a network node not directly connected to the hub network node and a failure of a portion of the transmission network not directly connected to the hub network node;
• and
• 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 delivery direction along the ring, forwarding the multicast data traffic in the first delivery direction along the ring, 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 delivery direction along the ring, forwarding the multicast data traffic in the second delivery direction along the ring, and transmitting the local data traffic to the first network node along the first delivery direction along the ring.

A communication network comprising:

• a first network node;
• at least two second network nodes;
• a transmission network connecting the first and second network nodes in a ring architecture;
• wherein:
• the first network node is adapted to deliver multicast data traffic over the communication network, and wherein the first network node and the at least two second network nodes implement a point-to-multipoint layer 2 protocol, the first network node including a multicast traffic delivery protection function adapted to:
• collect alarm signals indicative of a failure condition of the transmission network along the whole ring and of the at least two second network nodes, and
• based on a current state of the alarm signals:
• cause the delivery of the multicast data traffic in a first delivery direction along the ring when no fault is detected;
• delivering the multicast data traffic in a second delivery direction along the ring opposite to the first delivery direction if the collected alarm signals indicate a failure condition of a first type, wherein the failure condition of the first type comprises at least one of:
• a failure of a network node directly connected to the first network node and a failure of a portion of the transmission network between the first network node and the network node directly connected to the first network node;
• and
• delivering the multicast data traffic in both the first and second delivery directions along the ring if the collected alarm signals indicate a failure condition of a second type different from the first type, wherein the failure condition of the second type comprises at least one of:
• a failure of a network node not directly connected to the first network node and a failure of a portion of the transmission network not directly connected to the first network node;
• and
• each of the second network nodes is adapted to receive multicast data traffic delivered by the first network node, each second network node including a multicast traffic delivery protection function adapted to:
• collect local alarm signals indicative of a failure condition of the transmission network locally to the second network node and of the second network node, and
• 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 delivery direction along the ring, forwarding the multicast data traffic in the first delivery direction along the ring, 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 delivery direction along the ring, forwarding the multicast data traffic in the second delivery direction along the ring, and transmitting the local data traffic to the first network node along the first delivery direction along the ring.