US 5,852,602 A · Credit control method and system for ATM communication apparatus

Abstract

In a credit control method and system, an initial credit value is sent from a receiving-side to a sending-side prior to transferring a packet. Transfer of a packet is started on the sending-side when this credit value is received. On the receiving-side, a new credit value is calculated when the packet is received, and the same number of packets as the number indicated by the calculated new credit value are received and processed. A new credit value is sent to the sending-side whenever receiving buffers whose number equals the preceding new credit value are emptied. On the sending-side, the sum of the new credit value and the initial credit value, whenever the new credit value is received, is stored as a credit value indicating the number of successively transmittable packets. The stored credit value is decremented by one on the sending-side whenever a packet is sent, and packets are continuously transferred until the credit value becomes "0" or there is no more packet to be sent. An integral new credit value Cn calculated based on a condition: Ta+Tp.times.(Cn-1)<Tp.times.Ci where Ta is a time from transmission of the initial credit value to reception of the first packet on the receiving-side, Tp is a time required to send one fixed-length packet, and Ci is the initial credit value is Ci.

Claims11

Dependent claims

A credit control method for an ATM communication apparatus for performing data transfer of a fixed-length packet from a packet sending-side to a packet receiving side by flow control using credit information, comprising:

sending an initial credit value from said packet receiving-side to said packet sending-side prior to transferring a packet;
starting transfer of a packet on said packet sending-side when the initial credit value is received;
calculating a new credit value on said packet receiving-side when the packet is received from said packet sending-side;
receiving and processing the same number of packets as the number indicated by the calculated new credit value on said packet receiving-side;
sending a new credit value from said packet-receiving side to said packet sending side whenever a number of receiving buffers, equal to a number indicated by the preceding new credit values, are emptied;
storing, on said packet-sending side, a value obtained by adding the new credit value to the initial credit value from said packet receiving side, whenever the new credit value is received, as a credit value indicating the number of successively transmittable packets;
and
decrementing the stored credit value by one on said packet sending-side whenever a packet is sent and continuously transferring packets until the credit value becomes "0" or there are no more packets to be sent,
wherein the step of calculating the new credit value calculates an integer new credit value Cn on the basis of a condition
Ta+Tp.times.(Cn-1)<Tp.times.Ci
where Ta is a time from transmission of the initial credit value from said packet receiving-side to reception of a first packet on said packet-receiving side, Tp is a time required to send one fixed-length packet, and Ci is the initial credit value.

8 more elements

A credit control system for an ATM communication apparatus for performing data transfer of a fixed-length packet from a packet sending-side to a packet receiving-side by flow control using credit information, wherein

said packet sending-side comprises:
packet transfer means for starting transfer of a packet to said packet receiving-side in response to an initial credit value sent from said packet receiving-side;
first storage means for storing a value obtained by adding a new credit value to the initial credit value from said packet receiving-side, whenever the new credit value is received, as a credit value indicating the number of successively transmittable packets;
and
transfer control means for decrementing by one the credit value stored in said storage means whenever a packet is sent and completing the packet transfer when the credit value becomes "0" or there are no more packets to be sent,
said packet receiving-side comprises:
initial credit sending means for sending the initial credit value to said packet sending-side prior to transfer of a packet from said packet sending-side;
new credit calculating means for calculating a new credit value when receiving a packet sent from said packet sending-side in response to the initial credit;
receiving buffers for receiving a number of packets equal to the number indicated by the new credit value calculated by said new credit calculating means;
and
new credit sending means for sending a new credit value to said packet sending-side whenever a number of said receiving buffers equal to the number indicated by the new credit value are emptied in accordance with processing of the packets, and
said new credit calculating means calculates an integer new credit value Cn on the basis of a condition
Ta+Tp.times.(Cn-1)<Tp.times.Ci
where Ta is a time from transmission of the initial credit value from said packet receiving-side to reception of a first packet on said packet receiving-side, Tp is a time required to send one fixed-length packet, and Ci is the initial credit value.

11 more elements

Dependencies are inferred from the claim text.

Credit control method and system for ATM communication apparatus

Life of this patent

Credit control method and system for ATM communication apparatus

Life of this patent

Abstract

Claims11