Patent ID: 7983267

Claim:
A transmission apparatus connected to a first transmission apparatus and connected to a second transmission apparatus via a communications network, said transmission apparatus comprising: a switch which forwards a frame based on a label of the frame which identifies a first path and a second path; a first interface unit which communicates with the second transmission apparatus via the first path; a second interface unit which communicates with the second transmission apparatus via the second path which provides redundancy to the first path; a third interface unit which encapsulates a user frame received from a first physical port of said first transmission apparatus included in a link aggregation port and forwards the frame to the switch; a fourth interface unit which encapsulates a user frame received from a second physical port of said first transmission apparatus included in the link aggregation port and forwards the frame to the switch; and a first storage unit which stores information of the third interface unit and the fourth interface unit wherein ACT or SBY is set, respectively; wherein said third interface unit receives a user frame sent from the first physical port of said first transmission apparatus, and forwards the user frame to the second transmission apparatus by encapsulating the user frame with the label of the first path via the first path by said switch; wherein said fourth interface unit receives a user frame sent from the second physical port of said first transmission apparatus, and forwards the user frame to the second transmission apparatus by encapsulating the user frame with the label of the first path via the first path by said switch; wherein, when said third interface unit and fourth interface unit are respectively set to ACT, said third interface unit and said fourth interface unit respectively send a connectivity verification frame to said second transmission apparatus; wherein, when said third interface unit and fourth interface unit are respectively set to SBY, said third interface unit and said fourth interface unit respectively do not send a connectivity verification frame to said second transmission apparatus.