Patent ID: 7912087

Claim:
A capacity variable link apparatus including a main signal system and a control signal system, said main signal system comprising: an upper layer signal accommodation part for accommodating an upper layer signal; a lower layer path termination part; a signal switching part configured to divide said upper layer signal into lower layer signals in a lower layer path group having a capacity that is determined according to an amount of traffic of said upper layer signal, and configured to pass said lower layer signals to said lower layer path termination part; said control system comprising: a traffic amount measuring part configured to measure said amount of traffic that flows in said upper layer signal accommodation part, and to determine whether the capacity of said lower layer path group is to be increased or decreased according to said amount of traffic; a signal switching management part configured to control said signal switching part according to the result of determination by said traffic amount measuring part; and a lower layer path management control part configured to exchange control messages for path setting and exchange control messages for path deletion with another capacity variable link apparatus placed on a route according to the increase or decrease of said capacity of said lower layer path group, the signal switching management part controlling, based on the control messages, the signal switching part to set the lower layer path group as a virtual concatenation path or a trunked logical link, wherein, when a control message is received from the other capacity variable link apparatus, the lower layer path management part sends a request message to the signal switching management part to cause the signal switching management part to create a setting for the signal switching part, and the signal switching part edits the upper layer signal into the lower layer path group based on the setting, and the control message sent from the capacity variable link apparatus to the other capacity variable link apparatus includes trigger information for the other capacity variable link apparatus to edit the upper layer signal into the lower layer path group as the virtual concatenation path or the trunked logical link.