Re: [Discuss-gnuradio] tunnel.py destination host unreachable

[Alex Zhang]

I did the test by myself, and the most of the time ARP queries failed.... I met this problem when I do the OFDM link test, but that is because the physical layer is not robust. But for this narrow band (GMSK) modulation, I am not sure what the problem is.

May Josh knows... :)

On Fri, Jun 15, 2012 at 3:05 PM, Alex Zhang <address@hidden> wrote:

Something like discarded.

On Fri, Jun 15, 2012 at 11:59 AM, Weixian Zhou <address@hidden> wrote:

What do you mean by "it may be consumed"?

On Fri, Jun 15, 2012 at 12:44 PM, Alex Zhang <address@hidden> wrote:

Did you see RX False at the receiver for the ARP reply? If that is not seen, it could be due to some reason causing the ARP reply is not sent out at all. Although you see the log for the TX packet in the CSMA mainloop, but it may be consumed before or when  it goes to the transmitting path...

On Fri, Jun 15, 2012 at 10:49 AM, Weixian Zhou <address@hidden> wrote:

Yes, the ARP is replied. But another machine did not received and showed "Destination Host Unreachable".

On Fri, Jun 15, 2012 at 11:19 AM, Alex Zhang <address@hidden> wrote:

Do you check the ARP reply is sent out or not? 

I am not sure if there are some flow control issues for the networking. 

On Fri, Jun 15, 2012 at 10:02 AM, Weixian Zhou <address@hidden> wrote:

Thanks for responses. The problem that confused me is that when I

on machine A:

sudo ./tunnel.py --tx-freq=2.51G --rx-freq=2.515G -c 50 -r 0.5M 

then 

sudo ifconfig gr0 192.168.200.1

on machine B:

sudo ./tunnel.py --tx-freq=2.515G --rx-freq=2.51G -c 50 -r 0.5M 

then 

sudo ifconfig gr0 192.168.200.2

I can see packages tx/rx succeed on both machines. But the ping failed and one machine did not rx. Why is that?

On Thu, Jun 14, 2012 at 4:38 PM, Alex Zhang <address@hidden> wrote:

Most likely you did not set the freq and gain properly.  Unstable physical layer communications cause the ARP routing failure.

Please use different frequencies for tx and rx. 

On Thu, Jun 14, 2012 at 1:51 PM, Weixian Zhou <address@hidden> wrote:

I was testing with tunnel.py and following the instructions in README located in gnuradio/gr-digital/examples/narrwoband. 

I found that when I input ifconfig gr0 192.168.200.1 on machine A, and input ifconfig gr0 192.168.200.2 on machine B at the same time, both machines showed Tx and Rx packages.

But when I ping 192.168.200.2 from machine A ( or ping 192.168.200.1 from machine B respectively), one window of machine A only showed Tx packages and another window showed "Destination Host Unreachable". Machine B showed both Rx/Tx packages.

It means that machine B can successfully received packages from machine A but A failed to receive replied packages from machine B. It confused me that the packages tx/rx were succeed before the ping. Anyone has idea?

--

Regards,

Weixian Zhou

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--

Alex,

Dreams can come true – just believe.

--

Regards,

Weixian Zhou

--

Alex,

Dreams can come true – just believe.

--

Regards,

Weixian Zhou

--

Alex,

Dreams can come true – just believe.

--

Regards,

Weixian Zhou

--

Alex,

Dreams can come true – just believe.

--

Alex,

Dreams can come true – just believe.