Hi,

I'm not sure about the inner details of the code used for the CC2420 on 
the TelosB platform. Here is what I found:
http://docs.tinyos.net/index.php/CC2420

Anyway, it sounds as if the radio chip did a filtering of incoming 
messages. If the radio discards messages in hardware, then you cannot 
snoop in software. You would need to put the radio in some sort of 
promiscuous mode. There is probably a precompiler definition you can set 
to disable hardware filtering, but I don't know its name. Maybe someone 
more familiar with the CC2420 radio code could help?

A work-around might be to send all messages as broadcasts and include a 
destination field in your own message format, then do the filtering 
yourself.

Cheers,
Urs


On 8/29/10 3:06 PM, Xiaohui Liu wrote:
> I'm using TelosB.
>
> On Sun, Aug 29, 2010 at 2:13 AM, <[email protected] 
> <mailto:[email protected]>> wrote:
>
>     Hi,
>
>     What platform are you using? If you use, e.g., Iris motes and have
>     hardware acknowledgments enabled, the radio will filter messages
>     out that are neither broadcasts nor addressed to this node. So on
>     a platform where the radio filters messages you cannot do snooping.
>
>     Cheers,
>     Urs
>
>     -original message-
>     Subject: [Tinyos-help] Snoop not working
>     From: Xiaohui Liu <[email protected] <mailto:[email protected]>>
>     Date: 28/08/2010 22:28
>
>     Hi,
>
>     I'm calling AMSnooperC[9]$Receive to overhear unicast packets sent
>     by AMSenderC[9]$AMSend, but none of the packets are snooped.
>     However, AMReceiverC[9]$Receive is able to receive packets and
>     snoopers are closer to the sender than the receiver. Can you
>     please help me to locate what might go wrong here? Thanks.
>
>     --
>     -Xiaohui Liu
>
>     <<ATT00001..txt>>
>
>
>
>
> -- 
> -Xiaohui Liu

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