I am working with two USRPS wired connection with 25 dB attenuator between them 
so I didnt expect to much corruption of the packets.

The error seems to occur quicker at lower bit rates for some reason , like 
around after 10s of minutes for below 250 kbps and more like after an hour or 
more for 1 Mbps. Unfortunatly this makes it unusable for longer duration lower 
bandwidth tests until I find a way to fix the problem.

Has anyone else had this problem with tunnel.py?

Thanks,
Dave


________________________________
From: Tom Rondeau <trondeau1...@gmail.com>
To: David Barton <david.barto...@yahoo.com>
Cc: discuss-gnuradio@gnu.org
Sent: Thu, April 21, 2011 10:22:39 AM
Subject: Re: [Discuss-gnuradio] Tunnel.py exception


On Wed, Apr 20, 2011 at 9:25 AM, David Barton <david.barto...@yahoo.com> wrote:

I am running tunnel.py on gnuradio 3.3.0 . It run successfully for a while but 
after a period of time (around an hour) the following exception prints out:
>
>Rx: ok = True  len(payload) =   82
>Tx: len(payload) =   82
>Exception in thread Thread-1:
>Traceback (most recent call last):
>  File "/usr/lib64/python2.6/threading.py", line 525, in __bootstrap_inner
>    self.run()
>  File "/usr/local/lib64/python2.6/site-packages/gnuradio/blks2impl/pkt.py", 
>line 162, in run
>    ok, payload = packet_utils.unmake_packet(msg.to_string(), int(msg.arg1()))
>  File "/usr/local/lib64/python2.6/site-packages/gnuradio/packet_utils.py", 
>line 
>183, in unmake_packet
>    payload_with_crc = dewhiten(whitened_payload_with_crc, whitener_offset)
>  File "/usr/local/lib64/python2.6/site-packages/gnuradio/packet_utils.py", 
>line 
>95, in dewhiten
>    return whiten(s, o)        # self inverse
>  File "/usr/local/lib64/python2.6/site-packages/gnuradio/packet_utils.py", 
>line 
>91, in whiten
>    z = sa ^ random_mask_vec8[o:len(sa)+o]
>ValueError: shape mismatch: objects cannot be broadcast to a single shape
>
>
>After this exception the receive chain seems to stop working. I am still able 
>to 
>transmit but no receive packets are recorded.
>
>Anyone have any clue what could be causing this issue? 
>
>Thanks,
>Dave


I think that the problem is when the receiver thinks it has a zero-length 
packet 
(that is, something gets screwed up with the header and it sees 0's there). I'm 
not positive that this is the real problem, but I'd say it has something to do 
with a packet getting corrupted in a particular way that's causing this to 
happen.

We would need to put some protections into the unmake_packet to handle this as 
a 
dropped packet and then continue, once we find the exact problem.

Tom
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