Traffic generator with priority flow control

A method to generate and transmit test traffic over a network under test, comprising:

• scheduling a sequence of packets to be transmitted as the test traffic, each packet in the sequence of packets belonging to one of a plurality of flow control groups;
• and
• generating packets in the determined sequence to output completed packets for transmission over the network under test, generating packets further comprising:
• a pipeline of three or more processing engines, including a first processing engine, and a last processing engine, and a second processing engine intermediate the first processing engine and the last processing engine, performing respective sequential stages of a packet generation process;
• for each packet in the sequence of packets, the first processing engine storing first packet forming data in a first bank of first-in-first-out (FIFO) queues, the first bank of FIFO queues including a plurality of FIFO queues associated respectively with the plurality of flow control groups, the first processing engine storing the first packet forming data in the FIFO queue, from the first bank of FIFO queues, associated with the flow control group to which each packet belongs;
• for each packet in the sequence of packets, a second processing engine, intermediate the first processing engine and the last processing engine, storing second packet forming data in a second bank of first-in-first-out (FIFO) queues, the second bank of FIFO queues including a plurality of FIFO queues associated respectively with the plurality of flow control groups, the second processing engine storing the second packet forming data in the FIFO queue, from the second bank of FIFO queues, associated with the flow control group to which each packet belongs;
• the second processing engine providing the first processing engine with data indicating whether or not each FIFO queue in the second bank of FIFO queues can accept additional second packet forming data;
• and
• when one or more FIFO queues in the second bank of FIFO queues cannot accept additional second packet forming data, the first processing engine discontinuing performing the respective stage of the packet generation process for packets belonging to one or more corresponding flow control groups.

A non-transitory computer-readable storage medium storing configuration data which, when used to program a programmable device, configures the programmable device to include a traffic generator to transmit test traffic to test a network, the traffic generator comprising:

• a scheduler configured to determine a sequence of packets to be transmitted as the test traffic, each packet in the sequence of packets belonging to one of a plurality of flow control groups;
• a pipeline of three or more processing engines, including a first processing engine, and a last processing engine configured to output completed packets for transmission over the network under test, and a second processing engine intermediate the first processing engine and the last processing engine, each of the three or more processing engines configured to perform respective sequential stages of a packet generation process;
• and
• a first bank of first-in-first-out (FIFO) queues, the first bank of FIFO queues including a plurality of FIFO queues associated respectively with the plurality of flow control groups;
• and
• a second bank of FIFO queues, the second bank of FIFO queues including a plurality of FIFO queues associated respectively with the plurality of flow control groups, wherein:
• for each packet in the sequence of packets, the first processing engine stores first packet forming data in the FIFO queue, from the first bank of FIFO queues, associated with the flow control group to which each packet belongs and the second processing engine stores second packet forming data in the FIFO queue, from the second bank of FIFO queues, associated with the flow control group to which each packet belongs,
• the second processing engine is configured to provide the first processing engine with data indicating whether or not each FIFO queue in the second bank of FIFO queues can accept additional second packet forming data, and
• when one or more FIFO queues in the second bank of FIFO queues cannot accept additional second packet forming data, the first processing engine is configured to stop performing the respective stage of the packet generation process for packets belonging to one or more corresponding flow control groups.