Patent ID: 7397760
Filing Date: 2008-07-08
Classification: H04L

Abstract:
1. A transmission apparatus for accommodating a plurality of asynchronous networks and a plurality of SONET (Synchronous Optical Network) or SDH (Synchronous Digital Hierarchy) networks, said transmission apparatus comprising: a plurality of asynchronous network interface units each having an asynchronous network termination unit for inputting and outputting a packet from and to one of said asynchronous networks, and a mapping unit for carrying out a conversion process between said packet and a SONET/SDH frame, each of said plurality of asynchronous network interface units being used as a presently used line or a spare line; a plurality of SONET/SDH network interface units each used for interfacing with one of said SONET or SDH networks; a line exchange unit for carrying out line exchange processing between said mapping units and said SONET/SDH network interface units on the basis of line setting; a buffer provided only on a first asynchronous network interface unit used as the spare line; and a control unit for storing the packet output by a second asynchronous network termination unit used as the presently used line in the event of a line failure occurring in the SONET or SDH network on a route related to the second network interface unit and a packet output by said first asynchronous network termination unit into said buffer by adding identifiers for identifying said first and second asynchronous network termination units, and reading out said packets from said buffer, wherein: when the line failure does not occur in the SONET or SDH network on the route related to an asynchronous network interface unit used as the presently used line, the packet outputted from the asynchronous network interface unit used as the presently used line is outputted to the mapping unit included in the asynchronous network interface unit used as the presently used line, and when the line failure in the SONET or SDH network on the route related to said second asynchronous network interface unit occurs, the packets outputted from the first and second asynchronous network interface units read out from said buffer are outputted to the mapping unit included in the first asynchronous network interface unit.