mtu Test Suite

MTU update and jumbo frame forwarding test suite.

A suite of tests to ensures the consistency of jumbo and standard frame transmission within a DPDK application. If a NIC receives a packet that is greater than its assigned MTU length, then that packet should be dropped. Likewise, if a NIC receives a packet that is less than or equal to a designated MTU length, the packet should be accepted.

The definition of MTU between individual vendors varies with a +/- difference of 9 bytes, at most. To universally test MTU functionality, and not concern over individual vendor behavior, this test suite compensates using a 9 byte upper and lower bound when testing a set MTU boundary.

class TestMtu

Bases: TestSuite

DPDK PMD jumbo frames and MTU update test suite.

Assess the expected behavior of frames greater than, less then, or equal to a designated MTU size in a DPDK application.

Verify the behavior of both runtime MTU and pre-runtime MTU adjustments within DPDK applications. (Testpmd’s CLI and runtime MTU adjustment options leverage different logical in components within ethdev to set a value).

Test cases will verify that any frame greater than an assigned MTU are dropped and packets less than or equal to a designated MTU are forwarded and fully intact.

set_up_suite() → None

Set up the test suite.

Setup:

Set traffic generator MTU lengths to a size greater than scope of all test cases.

runtime_mtu_updating_and_forwarding() → None

Verify runtime MTU adjustments and assess packet forwarding behavior.

Steps:

  • Start testpmd in a paired topology.

  • Set port MTU to 1500.

  • Send packets of 1491, 1500 and 1509 bytes.

    • Verify the first two packets are forwarded and the last is dropped.

  • Set port MTU to 2400.

  • Send packets of 1491, 1500 and 1509 bytes.

    • Verify all three packets are forwarded.

  • Send packets of 2391, 2400 and 2409 bytes.

    • Verify the first two packets are forwarded and the last is dropped.

  • Set port MTU to 4800.

  • Send packets of 1491, 1500 and 1509 bytes.

    • Verify all three packets are forwarded.

  • Send packets of 4791, 4800 and 4809 bytes.

    • Verify the first two packets are forwarded and the last is dropped.

  • Set port MTU to 9000.

  • Send packets of 1491, 1500 and 1509 bytes.

    • Verify all three packets are forwarded.

  • Send packets of 8991, 9000 and 9009 bytes.

    • Verify the first two packets are forwarded and the last is dropped.

Verify:

  • Successful forwarding of packets via a search for an inserted payload. If the payload is found, the packet was transmitted successfully. Otherwise, the packet is considered dropped.

  • Standard MTU packets forward, in addition to packets within the limits of an MTU size set during runtime.

cli_mtu_forwarding_for_std_packets() → None

Assesses packet forwarding of standard MTU packets after pre-runtime MTU adjustments.

Steps:

  • Start testpmd with MTU size of 1518 bytes, set pre-runtime.

  • Send packets of size 1491, 1500 and 1509 bytes.

Verify:

  • First two packets are forwarded and the last is dropped.

  • Successful forwarding of packets via a search for an inserted payload. If the payload is found, the packet was transmitted successfully. Otherwise, the packet is considered dropped.

  • All packets are forwarded and the last is dropped after pre-runtime MTU modification.

cli_jumbo_forwarding_for_jumbo_mtu() → None

Assess packet forwarding of packets within the bounds of a pre-runtime MTU adjustment.

Steps:

  • Start testpmd with MTU size of 9018 bytes, set pre-runtime.

  • Send packets of size 8991, 9000 and 1509 bytes.

Verify:

  • Successful forwarding of packets via a search for an inserted payload. If the payload is found, the packet was transmitted successfully. Otherwise, the packet is considered dropped.

  • All packets are forwarded after pre-runtime MTU modification.

cli_mtu_std_packets_for_jumbo_mtu() → None

Assess boundary of jumbo MTU value set pre-runtime.

Steps:

  • Start testpmd with MTU size of 9018 bytes, set pre-runtime.

  • Send a packets of size 8991, 9000 and 9009 bytes.

Verify:

  • First two packets are forwarded and the last is dropped.

  • Successful forwarding of packets via a search for an inserted payload. If the payload is found, the packet was transmitted successfully. Otherwise, the packet is considered dropped.

  • Packets are forwarded and the last is dropped after pre-runtime MTU modification.

tear_down_suite() → None

Tear down the test suite.

Teardown:

Set the MTU size of the traffic generator back to the standard 1518 byte size.

required_capabilities: ClassVar[set[Capability]] = {28}

The capabilities the test case or suite requires in order to be executed.