Re: [Discuss-gnuradio] Tun/Tap Problem while Running tunnel.py while wireshark recognizes

[Jay Prakash]

Yes I have tested using different frequency.No help.

And while debugging I figured out that PHY layer receives the packet from transmitter sent as ping ICMP packets and decodes the sender's address.

After that it writes to the tun/tap. But tun/tap reply is unavailable.

Ie there is some problem in tun/tap and PHY layer interface.

How to figure this out?

Jay Prakash 

Senior Undergraduate 

Electronics Engineering

IIT (BHU)

VARANASI

+91-9559475258

http://about.me/jay.prakash/

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On Mon, Jun 10, 2013 at 7:13 PM, Tom Rondeau <address@hidden> wrote:

On Thu, Jun 6, 2013 at 3:22 PM, Jay Prakash
<address@hidden> wrote:
> We are working on establishing a tunnel for MAC protocol design using
> tunnel.py given as example in GNU Radio but are unable to receive ping reply
> from the other node.
>
> We created tun/tap interface using ./tunnel.py -f 990M and ipconfig
> 192.168.200.1 on Machine A connected to N210 series of USRP.
> and ./tunnel.py -f 990M and ifconfig 192.168.200.2 on machine B.
>
> 1. Now on pinging machine B from A we can see ping packets being sent to B
> by A using wireshark, but there is no reply on node A.
>
> 2. We went into details and saw there were ARQ requests from B repetitively.
> I manually added the mac address to update the table.
> Now ARQ request ceased to exist but still there were no replies on A.
>
>
> 3. Since we knew the Packaging details of ICMP we read the packets being
> received by B and found the exact source address of A from the frame. It
> means message have been successfully decoded by the destination and it knows
> whom to reply for the ping but still I don't find any reception confirmation
> on source side.
>
> What may be the possible problems?USRP antenna gain?Packets collision?
>
> In short we are unable to use tunnely.py  and are seeking for possible
> causes.
>
> Jay Prakash
> Senior Undergraduate

You could be having gain issues. Test this using the standard
uhd_siggen and uhd_fft programs to understand what settings give you
the best gain.

Also, try using different frequencies for transmit and receive (use
the -h on the command line to figure out how to do this).

Tom