Flexible network test apparatus

1. A network card configurable in a first mode or a second mode, comprising:

a scheduler to schedule packets to be generated, the scheduler providing, for each packet to be generated, a stream identifier and variable data;

four 10 GHz transmit engines to generate packets at a data rate of 10 GHz, each transmit engine further comprising:

a template memory storing a plurality of packet templates associated with a corresponding plurality of streams,

a background engine to select a packet template from the template memory for each packet to be generated in accordance with the respective stream identifier provided by the scheduler, and

an overlay fill engine to insert the respective variable data provided by the scheduler into the selected packet template;

four 10 GHz receive engines to receive and process packets at a data rate of 10 GHz; and

when configured in the first mode, further comprising:

four 10 GHz network interface units coupled to respective ones of the four 10 GHz transmit engines and the four 10 GHz receive engines, each 10 GHz network interface unit adapted to transmit packets generated by the respective 10 GHz transmit engine to a network under test and to direct packets received from the network under test to the respective 10 GHz receive engine,

wherein the scheduler is configured in the first mode to schedule four independent 10 GHz packet streams to be generated by respective ones of the four 10 GHz transmit engines;

when configured in the second mode, further comprising:

a coherent multiplexer to combine packets generated by the four 10 GHz transmit engines into test traffic at a 40 GHz data rate,

a packet distribution engine to accept packets at a 40 GHz data rate and distribute the accepted packets between the four 10 GHz receive engines, and

a 40 GHz network interface unit coupled to the coherent multiplexer and the packet distribution engine, the 40 GHz network interface unit adapted to transmit the test traffic formed by the coherent multiplexer to a network under test and to direct traffic received from the network to the packet distribution engine,

wherein the scheduler is configured in the second mode to schedule one 40 GHz packet stream to be generated by the four 10 GHz transmit engines collectively.

2. The network card of claim 1 , wherein

the network card comprises one or more programmable hardware devices, and

the network card is configured in one of the first mode and the second mode by programming the one or more programmable hardware devices.

3. An apparatus for testing a network, comprising:

a network card configurable in a first mode to provide N bidirectional test ports operable at a first data rate, and configurable in a second mode to provide a single bidirectional test port operable at a second data rate higher than the first data rate, wherein N is an integer greater than one,

the network card further comprising:

a scheduler selectively configurable to schedule N test traffic streams at the first data rate in the first mode or one test traffic stream at the second data rate in the second mode, the scheduler providing, for each packet in the test traffic streams, a stream identifier and variable data;

N transmit engines to generate packets at the first data rate, each transmit engine further comprising:

a template memory storing a plurality of packet templates associated with a corresponding plurality of streams,

a background engine to select a packet template from the template memory for each packet to be generated in accordance with the respective stream identifier provided by the scheduler, and

an overlay fill engine to insert the respective variable data provided by the scheduler into the selected packet template;

N receive engines to receive and process packets at the first data rate;

wherein the network card is configured in one of the first mode and the second mode by programming one or more programmable hardware devices included in the network card.

4. The apparatus of claim 3 , wherein, when configured in the first mode, the network card further comprises:

N first-data-rate network interface units coupled to respective ones of the N transmit engines and the N receive engines, each first-data-rate network interface unit adapted to:

transmit packets generated by the respective transmit engine to a network under test at the first data rate, and

direct packets received from the network under test at the first data rate to the respective receive engine.

5. The apparatus of claim 3 , wherein, when configured in the second mode, the network card comprises:

a coherent multiplexer to combine packets generated by the N transmit engines into test traffic at the second data rate;

a packet distribution engine to accept packets at the second data rate and distribute the accepted packets between the N receive engines; and

a second-data-rate network interface unit coupled to the coherent multiplexer and the packet distribution engine, the second-data-rate network interface unit adapted to

transmit the test traffic formed by the coherent multiplexer to a network under test at the second data rate, and

direct traffic received from the network at the second data rate to the packet distribution engine.

6. The apparatus of claim 3 , where in the second data rate is essentially N times the first data rate.

7. A method to test a network, comprising:

configuring a network card in one of a first mode to provide four bidirectional 10 GHz test ports and a second mode to provide a single bidirectional 40 GHz test port;

a scheduler scheduling four 10 GHz packet streams, the scheduler providing, for each packet in the packet streams, a stream identifier and variable data;

four 10 GHz transmit engines generating packets for the four 10 GHz packet streams, generating each packet further comprising:

selecting a packet template from a template memory in accordance with the respective stream identifier provided by the scheduler, the template memory storing a plurality of templates associated with a corresponding plurality of streams, and

inserting the respective variable data provided by the scheduler into the selected packet template; and

when the network card is configured in the first mode:

transmitting the four 10 GHz packet streams to the network via the four 10 GHz test ports respectively,

receiving test traffic form the network via the four 10 GHz test ports, and

processing the test traffic with four 10 GHz receive engines, each receive engine coupled to a corresponding one of the four 10 GHz test ports;

when the network card is configured in the second mode:

coherently multiplexing the packets generated by the four 10 GHz transmit engines to form the 40 GHz packet stream,

transmitting the 40 GHz packet stream to the network and receiving 40 GHz test traffic from the network via the 40 GHz test port, and

distributing the received 40 GHz test traffic between the four 10 GHz receive engines.

8. The method for testing a network of claim 7 , wherein configuring the network card further comprises programming at least one programmable hardware device.

9. The method for testing a network of claim 7 , further comprising, when the network card is configured in the first mode:

reporting test results independently for each of the four 10 GHz receive engines.

10. The method for testing a network of claim 7 , further comprising, when the network card is configured in the second mode:

consolidating tests results from the four 10 GHz receive engines; and

reporting the consolidated results.

11. A machine-readable non-transitory storage medium storing configuration data which, when used to program one or more programmable devices, causes a network card to be configured in one of two selectable modes, the network card comprising:

a scheduler to schedule packets to be generated, the scheduler providing, for each packet to be generated, a stream identifier and variable data;

four 10 GHz transmit engines to generate packets at a data rate of 10 GHz, each transmit engine further comprising:

a template memory storing a plurality of packet templates associated with a corresponding plurality of streams,

a background engine to select a packet template from the template memory for each packet to be generated in accordance with the respective stream identifier provided by the scheduler, and

an overlay fill engine to insert the respective variable data provided by the scheduler into the selected packet template;

four 10 GHz receive engines to receive and process packets at a data rate of 10 GHz; and

when configured in the first mode, further comprising:

four 10 GHz network interface units coupled to respective ones of the four 10 GHz transmit engines and the four 10 GHz receive engines, each 10 GHz network interface unit adapted to transmit packets generated by the respective 10 GHz transmit engine to a network under test and to direct packets received from the network under test to the respective 10 GHz receive engine,

wherein the scheduler is configured in the first mode to schedule four independent 10 GHz packet streams to be generated by respective ones of the four 10 GHz transmit engines;

when configured in the second mode, further comprising:

a coherent multiplexer to combine packets generated by the four 10 GHz transmit engines into test traffic at a 40 GHz data rate,

a packet distribution engine to accept packets at a 40 GHz data rate and distribute the accepted packets between the four 10 GHz receive engines, and

a 40 GHz network interface unit coupled to the coherent multiplexer and the packet distribution engine, the 40 GHz network interface unit adapted to transmit the test traffic formed by the coherent multiplexer to a network under test and to direct traffic received from the network to the packet distribution engine,

wherein the scheduler is configured in the second mode to schedule one 40 GHz packet stream to be generated by the four 10 GHz transmit engines collectively.