Re: [Discuss-gnuradio] Diffirence between receive data from USRP and sent via UDP

[Marcus D. Leech]

On 20/09/11 09:55 PM, Luong Tan Phong wrote:

Hi Readers,

My PC has 2 gigabit ethernet controlers. I read data from USRP2 (UHD, COMPLEX_FLOAT32, sample rate = 2.5 MHz) and sent it to another PC via UDP protocol.

If I sent data to another PC directly (use IP address), in System Monitor view : Receiving = 10.0 MiB/s; Sending = 19.6 MiB/s.

    uhd_src = uhd_make_usrp_source(dev_addr, uhd::io_type_t::COMPLEX_FLOAT32, 1);

    uhd_src->set_center_freq(d_rf_freq,0);

    uhd_src->set_samp_rate(2500000);

uhd_src->set_gain(20);

    udp_dataSender = gr_make_udp_sink(sizeof(gr_complex), "192.168.1.54", udp_port, 1472, true);

    tb->connect(uhd_src, 0, udp_dataSender, 0);

If I sent data to another PC use broadcast address, in System Monitor view : Receiving = 10.0 MiB/s; Sending = 1.2 MiB/s.

    udp_dataSender = gr_make_udp_sink(sizeof(gr_complex), "192.168.1.255", udp_port, 1472, true);


Could you demonstrate to me the issues, please?

Thanks.


LTP

The udp_sink object doesn't support broadcast.  In a "sockets" interface, if you want to use
  a broadcast address, you have to *explicitly turn on* IP broadcast by setting the SO_BROADCAST
  option on the socket (and a few other housekeeping details).  The udp_sink block doesn't do this,
  it will only support unicast.

-- 
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org