Patent ID: 8675645

Claim:
A method for operating a wireless mesh data network comprising a plurality of network nodes (MN) including a source node (SN), at least one intermediate node (IN), and a destination node (DN), wherein data frames are transferred from the source node (SN) through the at least one intermediate node (IN) to the destination node (DN), the method comprising: checking, during transfer of a data frame at least some of said plural network nodes (MN) which receive the data frame, with reference to a precursor list assigned to the destination node (DN) of the data frame and containing details of immediately adjacent network nodes, whether the network node (MN) sending the data frame is included in the precursor list; transferring the data frame to a further network node (MN) if the network node (MN) sending the data frame is included in the precursor list; and discarding the data frame or performing an error recovery routine if the network node (MN) sending the data frame is not included in the precursor list; wherein an entry in the precursor list comprises a Media Access Control (MAC) address or an IP address, and a lifetime of the entry; and wherein the entry in the precursor list is deleted when the lifetime of the entry has expired.