Re: [Discuss-gnuradio] Running tunnel.py/benchmark tx.p y (OFDM) with XCVR2450?

[mleech]

The XCVR2450 hardware is incapable of full-duplex operation.  It *cannot* transmit and receive at the same time.

 

 

On Wed, 01 Feb 2012 18:05:53 +0100, Florian Schlembach wrote:

> > > We are now trying to establish an TCP/IP connection between both USRP2s
> > > with the tunnel.py script.
> > > Unfortunately, it says "Destination Host unreachable" when pinging the
> > > other USRP. We should have set up the tunnel correct as some packets are
> > > received and transmitted after having configured the IP address. The
> > > pinged USRPs is indicating the received icmp packet but there is still
> > > no confirmed ping-request though.
> > Short answer; dont do that. Yes, this particular USRP is a network
> > device, but that is completely unrelated to the purpose of tunnel.py.
> > You probably have to play with routing tables to make this work...
>
> Why is that unrelated to the purpose of tunnel.py? Shouldnt a simple 
> ping request be a basic application of using this TUN/TAP application?
> Anyway, we have now set up the routing table correctly by using TUN 
> instead of TAP.
> As we are transmitting the ping from one of the USRPs, we are also 
> receiving them at the RX-USRP which is answering with a ping reply:
>
> RX-USRP:
>
> -
> TIMEOUT
> Rx: ok = True  len(payload) =   84
> Tx: len(payload) =   84
> send now!
> UTIMEOUT
> -
>
> Observing the IP dataflow via Wireshark (at RX-USRP) confirms that.
> However, we are NOT receiving this ping reply and the transmitting USRP.
> It seems, like it cannot transmit and receive simultaneously. Exactky 
> the same happens if we swap the role of transmitting and receiving USRPs.
>
> Anybody has an idea how we could overcome this problem? Basically, we 
> want to measure the latency of a "real" application.
>
> _______________________________________________
>