Packet switch

Abstract

A virtual output queuing controlling device in an input buffering switch with a virtual output queuing technique includes a specialized class for CBR traffic, and a connection request generation section that makes a connection request for a switch scheduler, which can execute a three-step priority control. The connection request generation section makes the connection request of the specialized class for CBR traffic prior to the connection request of the other classes for the switch scheduler.

1 . A virtual output queuing controlling device in an input buffering switch with a virtual output queuing technique, comprising:
 a specialized class for a CBR (constant bit rate) traffic; and   a connection request generation section that makes a connection request for a switch scheduler, which can execute a three-step priority control, characterized in that said connection request generation section makes the connection request of said specialized class for the CBR traffic prior to the connection request of the other classes for said switch scheduler.   
   
   
       2 . The virtual output queuing controlling device according to  claim 1 , wherein said three-step priority control comprises steps of:
 a) determining whether a cell to be sent comprises a cell in said specialized class for the CBR traffic;   b) determining whether said cell to be sent, if it does not comprise a cell in said specialized class for the CBR traffic, comprises a conforming cell in any class other than said specialized class for the CBR traffic; and   c) determining whether said cell to be sent, if it does not comprise a cell in said specialized class for the CBR traffic and does not comprise a conforming cell in any class other than said specialized class for the CBR traffic, comprises a non-conforming cell in any class.   
   
   
       3 . The virtual output queuing controlling device according to  claim 1 , wherein said specialized class comprises a class for only a CBR traffic. 
   
   
       4 . The virtual output queuing controlling device according to  claim 3 , wherein said three-step priority control comprises steps of:
 a) determining whether a cell to be sent comprises a cell in said specialized class for only the CBR traffic;   b) determining whether said cell to be sent, if it does not comprise a cell in said specialized class for only the CBR traffic, comprises a conforming cell in any class other than said specialized class for only the CBR traffic; and   c) determining whether said cell to be sent, if it does not comprise a cell in said specialized class for only the CBR traffic and does not comprise a conforming cell in any class other than said specialized class for only the CBR traffic, comprises a non-conforming cell in any class.   
   
   
       5 . A virtual output queuing controlling device in an input buffering switch with a virtual output queuing technique, comprising:
 a first specialized class for a CBR (constant bit rate) traffic;   a second class for other traffics than the CBR traffic;   a cell read-out controlling section that reads out cells from each of said classes; and   a connection request generation section that makes a connection request for a switch scheduler, which can execute a two-step priority control, characterized in that, when said connection request generation section received the connection request from said switch scheduler, said cell read-out controlling section reads out the cells from said first class prior to said second class.   
   
   
       6 . The virtual output queuing controlling device according to  claim 5 , wherein said two-step priority control comprises steps of:
 a) determining whether a cell to be sent comprises a cell in said first specialized class for the CBR traffic; and   b) determining whether said cell to be sent comprises a conforming cell in any class.   
   
   
       7 . The virtual output queuing controlling device according to  claim 5 , wherein:
 said first specialized class comprises a class for only the CBR traffic, and   said second class comprises a class for all other traffics than the CBR traffic.   
   
   
       8 . The virtual output queuing controlling device according to  claim 7 , wherein said two-step priority control comprises steps of:
 a) determining whether a cell to be sent comprises a cell in said first specialized class for only the CBR traffic; and   b) determining whether said cell to be sent comprises a conforming cell in any class.   
   
   
       9 . An input buffering switch, comprising:
 a specialized class for a CBR (constant bit rate) traffic; and   a connection request generation section that makes a connection request for a switch scheduler, which can execute a three-step priority control, characterized in that said connection request generation section makes the connection request of said specialized class for the CBR traffic prior to the connection request of the other classes for said switch scheduler.   
   
   
       10 . The input buffering switch according to  claim 9 , wherein said three-step priority control comprises steps of:
 a) determining whether an input cell comprises a cell in said specialized class for the CBR traffic;   b) determining whether said input cell, if it does not comprise a cell in said specialized class for the CBR traffic, comprises a conforming cell in any class other than said specialized class for the CBR traffic; and   c) determining whether said input cell, if it does not comprise a cell in said specialized class for the CBR traffic and does not comprise a conforming cell in any class other than said specialized class for the CBR traffic, comprises a non-conforming cell in any class.   
   
   
       11 . The input buffering switch according to  claim 9 , wherein said specialized class comprises a class for only a CBR traffic. 
   
   
       12 . The input buffering switch according to  claim 11 , wherein said three-step priority control comprises steps of:
 a) determining whether an input cell comprises a cell in said specialized class for only the CBR traffic;   b) determining whether said input cell, if it does not comprise a cell in said specialized class for only the CBR traffic, comprises a conforming cell in any class other than said specialized class for only the CBR traffic; and   c) determining whether said input cell, if it does not comprise a cell in said specialized class for only the CBR traffic and does not comprise a conforming cell in any class other than said specialized class for only the CBR traffic, comprises a non-conforming cell in any class.   
   
   
       13 . An input buffering switch, comprising:
 a first specialized class for a CBR (constant bit rate) traffic;   a second class for other traffics than the CBR traffic;   a cell read-out controlling section that reads out the cells from each of said classes; and   a connection request generation section that makes a connection request for a switch scheduler, which can execute a two-step priority control, characterized in that, when said connection request generation section received the connection request from said switch scheduler, said cell read-out controlling section reads out the cells from said first class prior to the cells from said second class.   
   
   
       14 . The input buffering switch according to  claim 13 , wherein said two-step priority control comprises steps of:
 a) determining whether an input cell comprises a cell in said first specialized class for the CBR traffic; and   b) determining whether said input cell comprises a conforming cell in any class.   
   
   
       15 . The input buffering switch according to  claim 13 , wherein:
 said first specialized class comprises a class for only a CBR traffic, and   said second class comprises a class for all other traffics than the CBR traffic.   
   
   
       16 . The input buffering switch according to  claim 15 , wherein said two-step priority control comprises steps of:
 a) determining whether an input cell comprises a cell in said first specialized class for only the CBR traffic; and   b) determining whether said input cell comprises a conforming cell in any class.