I got the reason, the tossim message type is not the same with the cc2420
message type,
but I still have a question:

the doc  http://www.tinyos.net/tinyos-2.x/doc/html/tep111.html says the
CC2420 has 7 bytes in meta, but the definition of cc2420_metadata_t is like
this,
typedef nx_struct cc2420_metadata_t {
  nx_uint8_t rssi;
  nx_uint8_t lqi;
  nx_uint8_t tx_power;
  nx_bool crc;
  nx_bool ack;
  nx_bool timesync;
  nx_uint32_t timestamp;
  nx_uint16_t rxInterval;

  /** Packet Link Metadata */
#ifdef PACKET_LINK
  nx_uint16_t maxRetries;
  nx_uint16_t retryDelay;
#endif
} cc2420_metadata_t;

It seems not 7 bytes.

2011/7/18 崔晓宗 <[email protected]>

> In http://www.tinyos.net/tinyos-2.x/doc/html/tep111.html , it says The
> CC2420 header is 11 bytes long.
> But I print the length of each field of message_t with dbg() in tossim,
> "%d %d %d %d %d
> \n",sizeof(message_t),sizeof(message_header_t),TOSH_DATA_LENGTH,sizeof(message_footer_t),sizeof(message_metadata_t)
> I got the following result:
> 41 7 28 2 4
>
> Why the header length is 7, and why the footer length is 2 while the doc
> says that cc2420 don't have a footer?
> --
> Regards,
> Xiaozong Cui
>
>


-- 
Regards,
Xiaozong Cui
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