Method and device for label automatic allocation in ring network protection

A method for label retention in ring network protection, comprising:

• after a ring tunnel bears a service, if a first node is an intermediate node on the ring tunnel, receiving, by the first node, a first label retention message sent by a downstream node;
• and
• if connectivity detection between the first node and the downstream node is Down, retaining, by the first node according to the first label retention message, a first label allocated by the downstream node for the ring tunnel, and after the connectivity detection between the first node and the downstream node is updated to UP, continuing to forward the service by adopting the retained first label allocated by the downstream node for the ring tunnel,
• wherein the first node and the downstream node are adjacent nodes on the ring tunnel.

A communication device, wherein the communication device is a physical device on a ring network, and the communication device is an intermediate node of a ring tunnel, the communication device comprising:

• a detecting unit, configured to, after physical topology configuration of ring network protection is completed, detect connectivity between adjacent nodes;
• a receiving unit, configured to receive a first label distribution message sent by a downstream device, wherein the first label distribution message comprises:
• an identifier of a ring bearing the ring tunnel, an identifier of a tail device of the ring tunnel, an identifier indicating that a tail device label is ready, and a first label allocated by the downstream device for the ring tunnel;
• and
• a sending unit, configured to, when the first label distribution message received by the receiving unit comprises the identifier indicating that the tail device label is ready, and when the detecting unit detects that connectivity between the communication device and an upstream device is UP, send a second label distribution message to the upstream device, wherein the second label distribution message comprises:
• the identifier of the ring bearing the ring tunnel, the identifier of the tail device of the ring tunnel, the identifier indicating that the tail device label is ready, and a second label allocated by the communication device for the ring tunnel;
• so that the upstream device learns, according to the identifier indicating that the tail device label is ready, that label allocation for all devices on the ring tunnel between the communication device and a tail device corresponding to the identifier of a tail device of the ring tunnel is completed, wherein the upstream device and the communication device are adjacent devices on the ring tunnel, and the communication device and the downstream device are adjacent devices on the ring tunnel.