Patent ID: 6879594

Claim:
A method for preventing routing loop from forming when joining a node to a Multi-Protocol Label Switching tree, comprising the steps of: a) obtaining at a label switching router (LSR)a label mapping for a forwarding equivalency class (FEC); b) determining if previous bindings exist for said FEC: c) determining if said joining node is a signal node or a parent node of a subtree; d) accepting the mapping for said single node if no previous bindings exist; and if said previous bindings exist when said subtree is attached to said Multi-Protocol Label Switching tree: e) sending a label splice message (Lsm) from said LSR to a root-node on a label switched path and returning a label splice message acknowledgement (ACK) to said LSR, and f) accepting the mapping after receiving said ACK at said LSR; g) terminating any further action if said LSR is waiting for a previous ACK message, h) forwarding said Lsm to the next LSR if said LSR is not waiting for said previous ACK message.