| 主权项 |
1. A communication network system comprising:
a plurality of edge equipments (AEs) on an access line side that accommodate an access line; and a plurality of backhaul edge equipments (BHEs) connected to a network side, wherein each of the BHEs is located at a top of a tree structure formed in a relay network including the plurality of AEs, and includes communication paths with the plurality of AEs; includes an intercommunication path through which a data signal does not flow in a normal operation and the data signal is mutually transmitted and received as a traffic accommodation path in an emergency between each of the plurality of BHEs, each of which is at the top of the tree structure; and includes a BHE transfer table which stores in advance a correlation between an input communication path and an output communication path, and an inter-BHE path table which stores in advance a correlation between an input communication path and an output communication path in the intercommunication path, wherein each of the plurality of AEs has communication paths for the plurality of BHEs, and is connected to the plurality of BHEs in advance via paths independent from one another; sets an active system path for one of the plurality of BHEs which are tops of a plurality of tree structures to which the self AE belongs, and sets a standby system path for one or a plurality of BHEs among the other BHEs; wherein the AE, in a normal operation state, receives data communication from a first BHE, and periodically receives a connection checking frame for checking normality of a communication path in order to monitor communication circumstances of a first communication path between the AE and the first BHE; the AE determines that a failure occurs in the first communication path when a subsequent connection checking frame is not received until a specific time has elapsed; and the AE sends a path switching request frame to a second BHE using a second communication path with the second BHE in which abnormality is not recognized on the communication path, wherein, when the second BHE receives the path switching request frame transmitted by the AE, the second BHE recognizes that some sort of problem which disrupts continuous communication between the AE and the first BHE occurs; the second BHE makes the second communication path connected between the AE and the second BHE valid as a main signal path in a second BHE transfer table in the second BHE, sets a communication path directed to the AE using the intercommunication path connecting the first BHE and the second BHE for a downlink signal to the AE, and changes settings so as to set a transmission path by the intercommunication path for an uplink signal from the AE; and the second BHE further transmits a transfer request frame for accommodating communication which is directed to the AE from the first BHE in the intercommunication path, to the first BHE, wherein, when the first BHE receives the transfer request frame from the second BHE, the first BHE changes settings in the first BHE transfer table in the first BHE so as to switch a path, which receives an uplink signal from the AE, from the first communication path to the intercommunication path; and the first BHE further changes settings in the first BHE transfer table so as to transfer a downlink signal directed to the AE received from the network to the intercommunication path, in relation to the downlink signal to the AE which has been transferred using the first communication path connecting the first BHE to the AE, and wherein a sub-tree having a sub-tree structure in which the second BHE of a standby system by passing a failure point is placed as a top is built under the first BHE of an active system, and communication between the AE and the first BHE of the active system is relayed by a standby system path via the second BHE of the standby system. |
