Patent ID: 8768162

Claim:
A method for realizing primary and backup link protection in a passive optical network (PON), the method comprising, establishing a PON ring between at least two optical line terminations (OLTs) through at least two user side edge nodes, a topology of the PON ring is an inverse-connection of at least two Point-to-Multipoint trees, wherein the at least two user side edge nodes are at least two optical network terminals (ONTs), or are at least two optical network units (ONUs), and each of the OLTs is coupled to any other OLT in the PON ring through the at least two edge nodes, the at least two OLTs are roots of the at least two Point-to-Multipoint trees, and the at least two user side edge nodes are leaves of the at least two Point-to-Multipoint trees; and configuring two links respectively in a clockwise direction and a counterclockwise direction in the PON ring, wherein one link is a primary link and the other link is a backup link; when the primary link is normal, receiving data via the primary link by the nodes in the PON ring, and when the primary link fails, notifying the nodes in the PON ring of a failure and receiving the data via the backup link by the nodes in the PON ring; when the primary link is normal, in a first transmitting and receiving mode, transmitting data via the primary link and the backup link by the nodes in the PON ring and receiving the data via only the primary link by the nodes in the PON ring; and when the primary link is normal, in a second transmitting and receiving mode, transmitting and receiving data via only the primary link by the nodes in the PON ring.