ATM exchange system and priority control method

Claim 2

The ATM exchange system of claim 1, wherein said priority control means outputs cells stored in buffers to said output channel according to a priority defined by said band width demand classes.

Claim 3

The ATM exchange system of claim 1 or 2, wherein said call reception control means comprises means for determining a band width demand class to which a generated call belongs.

Claim 4

An ATM exchange system for receiving a plurality of calls each having different required communication quality comprising: a first buffer for providing each of a plurality of band width demand classes that have been defined according to required communication quality for storing call cells belonging to said respective band width demand classes; a first counter for providing said respective band width demand classes; a second buffer for providing each of plurality of best effort classes that have been defined according to required communication quality for best effort transfer for storing call cells belonging to respective best effort classes; a second counter for providing said respective best effort classes; call reception control means for setting a guaranteed band width represented by a number of cells per certain time required to be output to an output channel for assuring each communication quality of said band width demand classes in a first counter of said respective band width demand classes at said certain time interval and setting each of values defined by a ratio of each of said respective best effort classes to use a remained band width resulted from taking a guaranteed band width from a whole band width of said output channel that is represented by said number of cells that can be output to said output channel within said certain time in said respective second counters when at least one of said second counters has a count value 0 and all best effort classes are in suspended status; and a priority control means for outputting cells stored either in said first buffer or said second buffer for a band width demand class or a best effort class, respectively having a counter value not set to 0, subtracting 1 from a value of either a first counter or a second counter of a band width demand class or a best effort class, respectively that has output cells at every output of cells to said output channel and outputting cells stored in said first buffer or said second buffer of a band width demand class or a best effort class, respectively having a counter value 0 to said output channel.

Claim 5

The ATM exchange system of claim 4, wherein said priority control means outputs cells stored in a buffer for said band width demand class with priority over cells stored in a buffer for said best effort class to said output channel and, when outputting cells of said band width demand classes, for outputting cells stored in a buffer to said output channel according to a priority defined by band width demand classes.

Claim 6

The ATM exchange system of claim 4 or 5, wherein said suspended status represents that said second counter value is 0 or said second buffer has an empty area.

Claim 7

The ATM exchange system of any of claims 1 to 6, wherein said call reception control means complising means for setting a guaranteed band width wider than a logically obtained guaranteed band width in said counter.

Claim 8

An ATM exchange system for receiving a plurality of calls each having different required communication quality comprising: a first buffer for providing each of a plurality of band width demand classes that have been defined according to required communication quality for storing call cells belonging to said respective band width demand classes; a first counter for providing said respective band width demand classes; a second buffer for providing each of plurality of best effort classes that have been defined according to required communication quality for best effort transfer for storing call cells belonging to said respective best effort classes; a second counter for providing each of said respective best effort classes; a third counter for providing each of said band width demand classes and said best effort classes; call reception control means for setting a guaranteed band width represented by a number of cells per certain time required to be output to an output channel for assuring each communication quality of said respective band width demand classes in a first counter of each of said respective band width demand classes at said certain time interval and setting each of values defined by a ratio of each of said respective best effort classes to use a remained band width resulted from taking a guaranteed band width from a whole band width of said output channel that is represented by said number of cells that can be output to said output channel within said certain time in said respective second counters when at least one of said second counters has a count value 0 and all best effort classes are in suspended status; addition means for setting a value obtained by adding a count value of said first counter to a count value of a third counter corresponding to a band width demand class of said first counter in said third counter just before setting a guaranteed band width in a first counter of a band width demand class and setting a value obtained by adding a count value of said second counter to a count value of a third counter corresponding to a best effort class of said second counter in said third counter just before setting a value in a second counter for each of said respective best effort classes; and priority control means for outputting cells stored in said first buffer of a band width demand class having a value of said first counter not set to 0 to said output channel, subtracting 1 from a value of a first counter of a band width demand class that has output cells at every output of cells to said output channel, outputting cells stored in said first buffer of a band width demand class having a value of said first counter set to 0 and a value of said third counter not set to 0 to said output channel, subtracting 1 from a value of a third counter of a band width demand class that has output cells at every output of cells to said output channel, outputting cells stored in said second buffer for a best effort class having a value obtained by adding a value of said second counter to a value of said third counter not set to 0 to said output channel, subtracting 1 from a value of either a second counter or a third counter of a best effort class that has output cells at every output of cells to said output channel, and finally outputting cells stored in said first buffer for a band width demand class having both values of said first counter and third counter set to 0 to said output channel.

Claim 9

An ATM exchange system for receiving a plurality of calls each having different required communication quality comprising: a first buffer for providing each of a plurality of band width demand classes that have been defined according to required communication quality for storing call cells belonging to said respective band width demand classes; a first counter for providing each of said respective band width demand classes; a second buffer for providing each of plurality of best effort classes that have been defined according to required communication quality for best effort transfer for storing call cells belonging to said respective best effort classes; a second counter for providing each of said respective best effort classes; a third counter for providing each of said band width demand classes and said best effort classes; call reception control means for setting a guaranteed band width represented by a number of cells per certain time required to be output to an output channel for assuring each communication quality of said respective band width demand classes in a first counter of each of said respective band width demand classes at said certain time interval and setting each of values defined by a ratio of each of said respective best effort classes to use a remained band width resulted from taking a guaranteed band width from a whole band width of said output channel that is represented by said number of cells that can be output to said output channel within said certain time in said respective second counters when at least one of said second counters has a count value 0 and all best effort classes are in suspended status; addition means for setting a value obtained by adding a count value of said first counter to a count value of a third counter corresponding to a band width demand class of said first counter in said third counter just before setting a guaranteed band width in a first counter of a band width demand class and setting a value obtained by adding a count value of said second counter to a count value of a third counter corresponding to a best effort class of said second counter in said third counter just before setting a value in a second counter for each of said respective best effort classes; and priority control means for outputting cells stored in said first buffer for a band width demand class having a value of said first counter not set to 0 to said output channel, subtracting 1 from a value of a first counter of a band width demand class that has output cells at every output of cells to said output channel, outputting cells stored in said first buffer for a band width demand class having a value of said first counter set to 0, a value of said third counter not set to 0 and said number of cells stored in said first buffer equal to or larger than a first threshold value set with respect to said band width demand class, subtracting 1 from a value of a third counter of a band width demand class that has output cells at every output of cells to said output channel, outputting cells stored in said first buffer of a band width demand class having a value of said first counter set to 0, a value of said third counter not set to 0, said number of cells stored in a first buffer smaller than a first threshold value set with respect to said band width demand class, subtracting 1 from a value of a third counter of a band width demand class that has output cells at every output of cells to said output channel, then outputting cells stored in said second buffer for a best effort class having a value obtained by adding a value of said second counter to a value of said third counter not set to 0 to said output channel and subtracting 1 from a value either of a second counter or a third counter of a best effort class that has output cells at every output of cells to said output channel, and finally outputting cells stored in said first buffer for a band width demand class having both values of said first counter and said third counter set to 0.

Claim 10

The ATM exchange system of claim 9, wherein cells of said band width demand classes stored in buffers are output to said output channel according to a priority defined by band width demand classes.

Claim 11

The ATM exchange system of claim 9 or 10, wherein said suspended state represents that said second counter value is 0 or said second buffer has an empty area.

Claim 12

The ATM exchange system of any of claims 4 to 11, wherein said call reception control means comprises means for determining a class to which a generated call belongs.

Claim 13

The ATM exchange system of any of claims 1 to 12, wherein said call reception control means comprises means for rejecting a call when receiving said call is expected to exhaust a remained band width.

Claim 14

The ATM exchange system of any of claims 8 to 13, wherein said call reception control means comprises means for setting a logically obtained guaranteed band width in said counter.

Claim 15

The ATM exchange system of any of claims 4 to 14, wherein said priority control means comprises means for weighted rotational priority controlling band width demand classes having the same priority using a guaranteed band width for each of said respective band width demand classes as a weight.

Claim 16

The ATM exchange system of any of claims 9 to 15, wherein said priority control means comprises means for outputting cells stored in a first buffer for a band width demand class having a third counter value set to 0 and a number of cells larger than a second threshold value larger than said first threshold value that has been set with respect to a band width demand class next to a band width demand class having said third counter value not set to 0.

Claim 17

A priority control method for an ATM exchange system for receiving a plurality of calls each having different required communication quality comprising steps of: setting a plurality of band width demand classes according to required communication quality; first guaranteed band width set step for setting a guaranteed band width represented by a number of cells per certain time required to be output to an output channel for assuring communication quality of said respective band width demand classes in a counter of each of said respective band width demand classes at said certain time interval; determining a band width demand class to which a call belongs and storing call cells in a buffer of a corresponding band width demand class; output step for outputting cells stored in a buffer for a band width demand class having a counter vale not set to 0 with priority over cells stored in a buffer for a band width demand class having a counter value set to 0 to said output channel; and subtracting 1 from a value of a counter of a band width demand class that has output cells at every output of said cells to said output channel.

Claim 18

The priority control method of claim 17, wherein said output step outputs cells stored in buffers to said output channel according to a priority defined by band width demand classes in the presence of a band width demand class having values of two or more counters not set to 0.

Claim 19

The priority control method of claim 17 or 18, wherein said step for setting a guaranteed band width sets a guaranteed band width wider than a logically obtained guaranteed band width in said counter.

Claim 20

The priority control method of any of claims 17 to 19 further comprising steps of: setting a plurality of best effort classes according to required communication quality for best effort transfer; dividing a remained band width resulted from subtraction of a guaranteed band width which has been set at said first guaranteed band width set step from a whole band width of said output channel represented by a number of cells that can be output to said output channel per said certain time according to a ratio of each of said best effort classes to use said remained band width and setting resultant values in a counter for each of said best effort classes when at least one of counters for said best effort has a count value 0 and all best effort classes are in suspended status; outputting cells stored in a buffer for either a band width demand class or a best effort class having a counter value not set to 0 with priority over cells stored in a buffer for either a band width demand class or a best effort class having a counter value 0; and subtracting 1 from a counter value of either a band width demand class or a best effort class that has output cells at every output of cells to said output channel.

Claim 21

The priority control method of claim 20 further comprises steps of: providing a second counter for each of said band width demand classes and said best effort classes, respectively; setting a value obtained by adding a count value of said counter to a count value of a second counter corresponding to a band width demand class of said counter in said second counter just before setting a guaranteed band width in a counter of each of band width demand classes; setting a value obtained by adding a count value of said counter to a count value of a second counter corresponding to a best effort class of said counter in said second counter just before setting a value in a counter of each of best effort classes; outputting cells stored in a buffer for a band width demand class having a counter value not set to 0 to said output channel and subtracting 1 from a counter value of a band width demand class that has output cells at every output of cells to said output channel; outputting cells stored in a buffer for a band width demand class having a counter value 0 and a second counter value not set to 0 to said output demand and subtracting 1 from a value of a second counter that has output cells at every output of cells to said output channel; outputting cells stored in a buffer for a best effort class having a value obtained by adding a counter value to a second counter value not set to 0 to said output channel and subtracting 1 from a counter value of a best effort class that has output cells at every output of cells to said output channel; and outputting cells stored in a buffer for a band width demand class having both counter values 0 to said output channel.

Claim 22

The priority control method of claim 21 further comprises steps of: setting a first threshold value in a buffer for a band width demand class; and giving a priority to a band width demand class having a number of cells stored in a buffer for said band width demand class larger than said first threshold value over a band width demand class having said number of cells stored in a buffer for said band width demand class smaller than said first threshold value.

Claim 23

The priority control method of claim 22 further comprises steps of: setting a second threshold value larger than said first threshold value in a buffer for a band width demand class; and giving a priority to a band width demand class having a number of cells stored in a buffer for said band width demand class larger than said second threshold value over a band width demand class having said number of cells stored in a buffer for said band width demand class smaller than said second threshold value.