How can modify "send frame size" and "recv frame size" for NI-USRP in LabVIEW?

[Jeff100]

How can modify "send frame size" and "recv frame size" for NI-USRP in LabVIEW?

Best regards,

Hossein Jafari

[Shalini.M]

Hi Hossein, 

It seems like those are UHD results when using uhd_usrp_probe so I would assume they can't be modified. 
With that said, are you using the NI-USRP driver in LabVIEW to code? 
If so, could you give me more information on which LabVIEW functions use those parameters? 

[Jeff100]

Hi Shalini,

I tried both gnuradio USRP and NI-USRP (LabVIEW). I used examples of TX and RX vi's and trying to capture packets in wireshark for both transmitter and receiver sides. (such as "niUSRP EX Rx Continuous Async.vi" and "niUSRP EX Tx Continuous Async"). Even I tried several other vi's for transmitting text and video.

As you mentioned when I run "uhd_usrp_probe" command, in the beginning it shows send and receive packet size are same:

-- Current recv frame size: 1472 bytes
-- Current send frame size: 1472 bytes

but in wireshark traces (for both gnuradio and NI-USRP) I see different length for TX and RX sides.

for USRP in TX mode:
frame length is 1514, IP packet is 1500, UDP packet size is 1480 and data length is 1472 bytes.

while in RX mode:
frame length is 1506, IP packet is 1492, UDP packet size is 1472 and data length is 1464 bytes.

Best regards,

Hossein Jafari

[vvkakade]

Please refer to my answer here:

https://forums.ni.com/t5/USRP-Software-Radio/Modify-quot-send-frame-size-quot-and-quot-recv-frame-si...