Patent ID: 7352753

Claim:
A method for detecting duplicated frames in a mirrored data communication network system, the method comprising: creating and maintaining at least one data structure comprising one or more entries, an entry comprising key information for each one of the received data frames; receiving a data frame via a data communication network; computing an index to the data structure based on information acquired from the received data frame, the index pointing to an entry in the data structure; and when the entry corresponding to the computed index is empty or the entry does not comprise key information matching the key information in the received data frame, storing the key information of the received data frame on the entry; and forwarding the data frame to an upper software layer; when the entry corresponding to the computed index comprises the key information matching the key information in the received data frame, the method further includes, discarding the received data frame; and deleting the corresponding key information from the entry, wherein the mirrored data communications network system includes at least one sender, at least one receiver and at least two redundant physically separate data communication networks between the sender and receiver.