142. VLAN Offload Tests

The support of VLAN offload features by Poll Mode Drivers consists in:

  • the filtering of received VLAN packets,
  • VLAN header stripping by hardware in received [VLAN] packets,
  • VLAN header insertion by hardware in transmitted packets.

The filtering of VLAN packets is automatically enabled by the testpmd application for each port. By default, the VLAN filter of each port is empty and all received VLAN packets are dropped by the hardware. To enable the receipt of VLAN packets tagged with the VLAN tag identifier vlan_id on the port port_id, the following command of the testpmd application must be used:

rx_vlan add vlan_id port_id

In the same way, the insertion of a VLAN header with the VLAN tag identifier vlan_id in packets sent on the port port_id can be enabled with the following command of the testpmd application:

tx_vlan set port_id vlan_id

The transmission of VLAN packets is done with the start tx_first command of the testpmd application that arranges to first send a burst of packets on all configured ports before starting the rxonly packet forwarding mode that has been previously selected.

142.1. Prerequisites

Assuming that ports 0 and 1 are connected to a traffic generator’s port A and B. Launch the testpmd with the following arguments:

./build/app/testpmd -cffffff -n 3 -- -i --burst=1 --txpt=32 \
--txht=8 --txwt=0 --txfreet=0 --rxfreet=64 --mbcache=250 --portmask=0x3

The -n command is used to select the number of memory channels. It should match the number of memory channels on that setup.

Set the verbose level to 1 to display information for each received packet:

testpmd> set verbose 1
testpmd> vlan set filter on

142.2. Test Case: Enable receipt of VLAN packets and disable VLAN header stripping

Setup the mac forwarding mode:

testpmd> set fwd mac
Set mac packet forwarding mode

Enable the receipt of VLAN packets with VLAN Tag Identifier 1 on port 0:

testpmd> rx_vlan add 1 0
testpmd> vlan set strip off 0
testpmd> start
  rxonly packet forwarding - CRC stripping disabled - packets/burst=32
  nb forwarding cores=1 - nb forwarding ports=10
  RX queues=1 - RX desc=128 - RX free threshold=64
  RX threshold registers: pthresh=8 hthresh=8 wthresh=4
  TX queues=1 - TX desc=512 - TX free threshold=0
  TX threshold registers: pthresh=32 hthresh=8 wthresh=8
Configure the traffic generator to send VLAN packets with the Tag Identifier
1 and send 1 packet on port A.

Verify that the VLAN packet was correctly received on port B with VLAN tag 1.

Configure the traffic generator to send VLAN packets with not matched Tag Identifier and send 1 packet on port A.

Verify that the VLAN packet was not correctly received on port B with this not matched VLAN Tag.

142.3. Test Case: Enable receipt of VLAN packets and VLAN header stripping

Setup the mac forwarding mode:

testpmd> set fwd mac
Set mac packet forwarding mode

Enable the receipt of VLAN packets with VLAN Tag Identifier 1 on port 0:

testpmd> rx_vlan add 1 0
testpmd> vlan set strip on 0
testpmd> start
  rxonly packet forwarding - CRC stripping disabled - packets/burst=32
  nb forwarding cores=1 - nb forwarding ports=10
  RX queues=1 - RX desc=128 - RX free threshold=64
  RX threshold registers: pthresh=8 hthresh=8 wthresh=4
  TX queues=1 - TX desc=512 - TX free threshold=0
  TX threshold registers: pthresh=32 hthresh=8 wthresh=8
Configure the traffic generator to send VLAN packets with the Tag Identifier
1 and send 1 packet on port A.

Verify that the VLAN packet was correctly received on port B without VLAN tag 1.

142.4. Test Case: Disable receipt of VLAN packets

Disable the receipt of VLAN packets with Tag Identifier 1 on port 0. Send VLAN packets with the Tag Identifier 1 check that no packet is received on port B, meaning that VLAN packets are now dropped on port 0:

testpmd> rx_vlan rm 1 0
testpmd> start
rxonly packet forwarding - CRC stripping disabled - packets/burst=32
nb forwarding cores=1 - nb forwarding ports=8
RX queues=1 - RX desc=128 - RX free threshold=64
RX threshold registers: pthresh=8 hthresh=8 wthresh=4
TX queues=1 - TX desc=512 - TX free threshold=0
TX threshold registers: pthresh=32 hthresh=8 wthresh=8
testpmd> stop

Verify that no packet was received on port B.

142.5. Test Case: Enable VLAN header insertion in transmitted packets

Arrange to only send packets on port 0:

testpmd> set nbport 1
Number of forwarding ports set to 1

Arrange to send one VLAN packet with VLAN Tag Identifier 1 on port 0:

testpmd> tx_vlan set 1 0
testpmd> start tx_first

Verify that the packet is correctly received on the traffic generator side (with VLAN Tag Identifier 1)