ATM communication apparatus and bandwidth control method of the same

Abstract

An ATM communication apparatus and a bandwidth control method guarantee the minimum cell rate and limit the upper-limit for each of subscriber terminals, dynamically and fairly distribute the shared bandwidth based on the register status, and are easily applied to the system this is already operating the actual service. A traffic supervisory unit supervises traffic situations of upstream ATM cells, and a bandwidth controller controls an access bandwidth of each of the optical network units 3 - 1 to 3 - n based on receiving of effective ATM cells transmitted by a plurality of the optical network units 3 - 1 to 3 - n that the traffic supervisory unit detects. A control table of permission transmits an upstream cell for maintaining the access bandwidth judged by the bandwidth controller. A generator of permission to transmit an upstream cell for generating permission to transmit an upstream cell according to the access bandwidth judged by the bandwidth controller.

1 . A communication apparatus, which determines sizes of communication bandwidths which are permitted to a plurality of respective user terminals, issues a permission of transmission of data to the respective user terminals according to the sizes of the communication bandwidths, and receives data from the respective user terminals according to the issued permission of transmission of data, the communication apparatus comprising: 
 a bandwidth controller which dynamically determines the communication bandwidths which are permitted to the respective user terminals;    a bandwidth supervisory unit which supervises the data received from the respective user terminals, and supervises the communication bandwidths which the respective user terminals actually use;    a transmission permission issuing unit which respectively issues the transmission permission to the respective user terminals according to the communication bandwidths which are permitted to the respective user terminals,    wherein the bandwidth controller, with respect to the arbitrary user terminal determines:    an amount of bandwidth assigned to the arbitrary user terminal out of a shared bandwidth which is shared by the plurality of user terminals based on the communication bandwidth which is permitted to the arbitrary user terminal by the permission of transmission issued previous time and the communication bandwidth which the arbitrary user terminal actually uses and is supervised by the bandwidth supervisory unit, and    a calculated bandwidth which is obtained by adding the shared bandwidth which is determined to be assigned to the arbitrary user terminal and a basic bandwidth which is guaranteed to the arbitrary user terminal as the communication bandwidth which is permitted to the arbitrary user terminal next time.    
   
   
       2 . A communication apparatus according to  claim 1 , wherein the bandwidth controller, with respect to the arbitrary user terminal, judges whether the arbitrary user terminal requires a communication bandwidth larger than the communication bandwidth which is permitted to the arbitrary user terminal according to the permission of transmission previously issued, by comparing the communication bandwidth which is permitted to the arbitrary user terminal according to the permission of transmission issued previous time with the supervised actually used communication bandwidth.  
   
   
       3 . A communication apparatus according to  claim 2 , wherein, when the bandwidth controller judges that the arbitrary user terminal requires the larger communication bandwidth, the bandwidth controller determines to assign a portion of the shared bandwidth which is the communication bandwidth shared by the plurality of user terminals with the arbitrary user terminal.  
   
   
       4 . A communication apparatus according to  claim 1 , wherein the bandwidth controller, with respect to the arbitrary user terminal: 
 calculates an amount of bandwidth which is assigned to the arbitrary user terminal out of the shared bandwidth,    compares the calculated shared bandwidth with an upper-limit bandwidth which is an upper-limit value of a size of the shared bandwidth which is assigned to the arbitrary user terminal, and    determines the size of the shared bandwidth as the shared bandwidth to be assigned to the arbitrary user terminal when the calculated shared bandwidth is smaller than the upper-limit bandwidth, and determines the upper-limit bandwidth as the shared bandwidth to be assigned to the arbitrary user terminal when the calculated shared bandwidth is larger than the upper-limit bandwidth.    
   
   
       5 . A communication apparatus according to  claim 4 , wherein the bandwidth controller, with respect to the arbitrary user terminal: 
 calculates a sum of the upper-limit bandwidths of the user terminals to which a portion of the shared bandwidth is assigned,    calculates a rate that the upper-limit bandwidth of the arbitrary user terminal occupies with respect to the sum of the upper-limit bandwidths, and    calculates a portion of the shared bandwidth which corresponds to the calculated rate as the shared bandwidth to be assigned to the arbitrary user terminal.    
   
   
       6 . A communication apparatus according to  claim 4 , wherein the bandwidth controller: 
 calculates differentials which are values obtained by subtracting the upper-limit bandwidth from the calculated shared bandwidth with respect to the user terminals in which the calculated shared bandwidth is larger than the upper-limit bandwidth which is set as an upper-limit value of the size to the shared bandwidth to be assigned,    calculates the sum of the calculated differentials as a surplus bandwidth, and    assigns the surplus bandwidth to the user terminals which require the further communication bandwidth.    
   
   
       7 . A communication apparatus according to  claim 1 , wherein the communication apparatus further includes: 
 a timer which measures a predetermined time and notifies the bandwidth controller each time the predetermined time elapses,    wherein the bandwidth controller, upon receiving the notification from the timer, newly determines the communication bandwidths to be permitted next time to the respective user terminals.