On 09/07/2010 04:43 AM, Jorge Miguel wrote: > I installed GNU Radio on a ThinkPad Lenovo T4410 under Ubuntu 10.04. > After connecting the USRP2 with the original Ettus code on the SD card > D and F LEDs are ok and when executed: > > ~$ sudo find_usrps > No USRP2 found. > > I run wireshark or tcpdump to see what happens in my network and I got: > > ~$ sudo find_usrps > 00:50:c2:85:35:a2 hw_rev = 0x0400 > > If I stop the sniffer, I get again: > > ~$ sudo find_usrps > No USRP2 found. > > My problem is that 'find_usrps' only works when a sniffer is running. > How can it be explained? > > Jorge, > When a sniffer is running, the ethernet interface is placed into "promiscuous" mode in which all ethernet frames are processed and passed up to higher layers in the networking stack. In non-promiscuous mode, only frames that are addressed to the particular hosts ethernet address, and the broadcast address, are forwarded up the stack.
My understanding is that find_usrps sends out a broadcast packet, and the responding USRP2 replies using a broadcast packet, but even in non-promiscuous mode, the hosts interface should pass the broadcast traffic "upwards". I wonder if there's some interaction with firewall rules at play here as well? -- Marcus Leech Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
