nrf7002: raw_tx_packet sequence numbers out of order and some performance questions

Question

Hi, I am running the raw_tx_packet sample (ncs v3.1.0) on nrf7002dk with the following configuration (additions to prj.conf in the sample) 
 
 # APPLICATION
CONFIG_RAW_TX_PKT_SAMPLE_INTER_FRAME_DELAY_MS=1000
CONFIG_RAW_TX_PKT_SAMPLE_TX_MODE_FIXED=y
CONFIG_RAW_TX_PKT_SAMPLE_FIXED_NUM_PACKETS=10000
CONFIG_RAW_TX_PKT_SAMPLE_QUEUE_NUM=3

# RATE
CONFIG_RAW_TX_PKT_SAMPLE_RATE_VALUE=5
CONFIG_RAW_TX_PKT_SAMPLE_RATE_FLAGS=2

# DRIVER
CONFIG_NRF70_MAX_TX_AGGREGATION=1

# CHANNEL
CONFIG_RAW_TX_PKT_SAMPLE_CHANNEL=56 The captured output looks like this The expected behaviour is that each second there a new packet will be sent. However, the sequence numbers are not increasing monotonically. Rather, it seems like every each packet is sent twice, and odd sequence numbers are skipped. I did another test with very low values for CONFIG_RAW_TX_PKT_SAMPLE_INTER_FRAME_DELAY_MS and then I see even more duplicates and out of order sequence like 8004, 8012, 7086 etc. This leads to two questions 
 
 Is the nrf7002 doing retransmissions on raw tx packets? 
 Is there any sort of re-ordering of packets in the driver/rf7002? 
 
 I also have some questions about performance tuning. I saw some numbers posted in: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/protocols/wifi/stack_configuration.html#usage_profiles . None of those are using the raw packet tx injection. Is it possible to get close to those limits in this mode? Does the nrf7002 have e.g a known max number of smaller packets, lets say 600 bytes long that it can send per second? Best regards, Rulle

Amanda Hsieh · Accepted Answer

Hi, 
 We are checking this issue and will update when I collect enough information. 
 Regards, Amanda H.

Amanda Hsieh · Answer

Hi, 
 This was a regression in NCS 3.1.0 and fixed with - fw_if: src: Free up TX buffers for raw tx by kapbh · Pull Request #73 · zephyrproject-rtos/nrf_wifi . We are in the process of merging this into NCS and will let you know once done. 
 I saw some numbers posted in: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/protocols/wifi/stack_configuration.html#usage_profiles . None of those are using the raw packet tx injection. Is it possible to get close to those limits in this mode? 
 This sample was planned as a functional example use case. The sample needs feature improvement to achieve full performance. If required, please raise the feature improvement request to your regional sales manager or use the form of Sales related questions . 
 Does the nrf7002 have e.g a known max number of smaller packets, lets say 600 bytes long that it can send per second? 
 The transmit logic confirms to the Wi-Fi channel contention & backoff rules, and hence the TX packet rate depends on contention time, data rate used, payload, etc. This can be characterized in a clean environment for a fixed rate and payload. If you specify what exactly the requirement is, we can offer some suggestions. 
 -Amanda H.

nrf7002: raw_tx_packet sequence numbers out of order and some performance questions

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