ATM cell service apparatus accommodating an ATM cell in an optical asynchronous communications network through a North America asynchronous communications network

Abstract

After a DS3 signal is terminated by the DS3 interface circuit, an ATM cell is extracted by an ATM cell extraction circuit from a signal input through a DS3 network after performing an ATM mapping process. The ATM cell is mapped in a SONET frame by an ATM cell/N.A. new synchronous SONET STS mapping unit, and is transmitted to a SONET. When an STS signal is input from the SONET, an STS frame is terminated in an STS demapping circuit. An ATM cell is extracted by an ATM cell extraction circuit, and is mapped in the DS3 signal and transmitted by an ATM cell/N.A. asynchronous DS3 mapping unit.

1 . An ATM cell service apparatus which accommodates an ATM cell in an optical synchronous communications network through an N.A. (North America) asynchronous communications network, comprising: 
 an optical synchronous communications network signal terminating unit terminating a signal in an optical synchronous communications network;    an N.A. asynchronous communications network signal terminating unit terminating a signal in an N.A. asynchronous communications network;    first and second ATM cell extraction units respectively extracting an ATM cell from a signal of the optical synchronous communications network and a signal of the N.A. asynchronous communications network;    first and second ATM cell mapping units respectively mapping ATM cells respectively extracted by said first and second ATM cell extraction units in signals of the N.A. asynchronous communications network and the optical synchronous communications network respectively; and    first and second signal transmission units respectively transmitting a signal of the N.A. asynchronous communications network in which the ATM cell is mapped, and a signal of the optical synchronous communications network in which the ATM cell is mapped.    
   
   
       2 . The apparatus according to  claim 1 , further comprising: 
 an optical synchronous communications network interface unit connecting a signal for an optical synchronous communications network to an optical synchronous communications network; and    an ATM network interface unit connecting a signal for an optical synchronous communications network to an ATM network without intervening signal processing units.    
   
   
       3 . The apparatus according to  claim 2 , further comprising 
 at least said optical synchronous communications network signal terminating unit commonly to said optical synchronous communications network interface unit and an ATM network interface unit so that an amount of hardware of said ATM cell service apparatus can be reduced.    
   
   
       4 . The apparatus according to  claim 1 , wherein 
 said extracting second unit extracts an ATM cell from a signal obtained by directly mapping an ATM cell in an N.A. asynchronous communications network signal; and    said first extracting unit extracts an ATM cell from a signal obtained by mapping an ATM cell in a predetermined format in the N.A. asynchronous communications network signal, wherein    an amount of hardware can be reduced by sharing a part of the hardware of said first and second extraction units.    
   
   
       5 . (canceled)  
   
   
       6 . (canceled)  
   
   
       7 . A method of providing an ATM cell service in which an ATM cell is accommodated in an optical synchronous communications network through an N.A. (North America) asynchronous communications network, comprising: 
 (a) terminating a signal in an optical synchronous communications network;    (b) terminating a signal in an N.A. asynchronous communications network;    (c) extracting an ATM cell from one of a signal of the optical synchronous communications network and a signal of the N.A. asynchronous communications network;    (d) mapping the ATM cell extracted in step (c) in a signal of the other of N.A. asynchronous communications network and the optical synchronous communications network; and    (e) transmitting the signal in which the ATM cell is mapped.    
   
   
       8 . The method according to  claim 7 , further comprising: 
 (f) connecting a signal for an optical synchronous communications network to an optical synchronous communications network; and    (g) connecting a signal for an optical synchronous communications network to an ATM network without intervening signal processing units.    
   
   
       9 . The method according to  claim 7 , wherein 
 said step (c) comprises: 
 (h) extracting an ATM cell from a signal obtained by directly mapping an ATM cell in an N.A. asynchronous communications network signal; and  
 (i) extracting an ATM cell from a signal obtained by mapping an ATM cell in a predetermined format in the N.A. asynchronous communications network signal.  
   
   
   
       10 . (canceled)  
   
   
       11 . An ATM cell service apparatus which accommodates an ATM cell for synchronous and asynchronous communications networks, comprising: 
 a detection unit detecting an out of frame state, a loss of a signal, or a signal fault; and    a cell insertion unit mapping one of an idle cell and an unassigned cell in a synchronous frame upon receipt of a detection result from said detection unit.