The IEEE 802.15.4 specification for the PHY only allows for 1 byte to specify the PSDU size (the payload size for the MAC). 1 bit of that is reserved, so your whole MAC payload should only be < 127 bytes.
I don't know how Javier is able to send such a large payload, unless mutliple PHY packets are being sent, or 802.15.4 PHY packet documentation is not being followed somehow. I'd be interested to know though. Regards, Kurt --Forwarded Message Attachment-- From: [email protected] To: [email protected] Date: Wed, 25 Feb 2009 11:04:52 +0100 Subject: Re: [Tinyos-help] maximum packet size On Wed, 25 Feb 2009 14:25:29 +0800 Pratibha S <[email protected]> wrote: > Hi, > Is there any limit to the packet size inclusive of all the headers and crc? > The CC2420 TEP, says that the max size is 128 bytes according to 802.15.4 > spec, but it also says that you can increase the size by changing the > TOSH_DATA_LENGTH with a trade-off of potential interferences. Can I assume > that excepting the consequences, there is no limit on the packet size? > > Regards, > Pratibha > Hi! I send packets with a size of 133 bytes (5 bytes head and 128bytes payload) and I have not any problem. Anyway, I remember when I started with tinyos and mica2 motes, that packet size over almost 200 bytes give me problems. I think it must be any hardware limitation, but I didn't read the radio transceiver (in this case a cc1000) documentantion. If you need to know this, you should read your radio transceiver datasheet (it shoud be a cc2420 or a cc1000 chip) and the interfaces used to send messages over radio to see if there is any hardware/tinyos limitation. cheers -- Nunca confies en un S.O. del que no tienes código fuente ;-) -------------------------------- Javier Almansa Sobrino. Ingeniero Técnico en Informática de Sistemas. FSF #7032 Member (www.fsf.com) Grupo de Investigación ARCo. Escuela Superior de Informática. Ciudad Real Tel: (+34)926 29 53 00 Ext: 3705 --Forwarded Message Attachment-- From: [email protected] CC: [email protected]; [email protected] To: [email protected] Date: Wed, 25 Feb 2009 10:08:16 +0000 Subject: Re: [Tinyos-help] maximum packet size Hi, Two following discussions may be the ones you need: http://mail.millennium.berkeley.edu/pipermail/tinyos-help/2007-August/027614.html http://mail.millennium.berkeley.edu/pipermail/tinyos-help/2006-April/016195.html Ittipong On 25/02/2009, Ruben Catteeuw <[email protected]> wrote: > > Hi, > > I think there must be a hardware-limit on the packet size. > > regards > > Ruben > > Date: Wed, 25 Feb 2009 14:25:29 +0800 > From: [email protected] > To: [email protected] > Subject: [Tinyos-help] maximum packet size > > Hi, > Is there any limit to the packet size inclusive of all the headers and crc? > The CC2420 TEP, says that the max size is 128 bytes according to 802.15.4 > spec, but it also says that you can increase the size by changing the > TOSH_DATA_LENGTH with a trade-off of potential interferences. Can I assume > that excepting the consequences, there is no limit on the packet size? > > Regards,Pratibha >
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