Hi David, On Tue, Aug 11, 2009 at 9:09 PM, David Li<[email protected]> wrote: > > Hi Mikos, > > I looked into the overhead inside message_t and it's surprise that it's > quite big too for RF230. > > 1. message_header_t: This is the same as IEEE154_header_t so it's 13 bytes > > 2. message_footer_t: This is rf230packet_footer_t which is zero > > 3. meassage_metadata_t: This is rf230packet_metadata_t and it is 7 bytes > without LP listening. > > 4. The TOSH_DATA_LENGTH is 28 by default. So the total packet size is 28 + > 13 + 7 = 48 by default as long as the payload stays within 28 bytes. So > this gives the total overhead of 13 + 7 = 20 bytes.
Yes that is correct. I would not name the ieee154_header an overhead, since you cannot really do anything about it. The 7 bytes is 4-byte timestamp, 1-byte lqi, 1-byte tx-power shared with rssi, and 1-byte flags. That is quite minimal. But overall, you are absolutely right, the total payload is quite small compared to the size of message_t. Miklos _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
