[mc1322x] [Contiki-developers] Broadcast PAN on Router solicitation

[Jon Smirl]

On Tue, Nov 17, 2009 at 10:29 PM, David Kopf <dak664 at embarqmail.com> wrote:
> Looking at those pcaps, the 13224 has an extra bit set in the frame control
> field, 0xc841 vs. 0xc801 for the Raven.
> Not sure what that bit means,

The extra bit is the Intra-PAN bit which is set when both the PAN's match.

but the raven has ffff ffff cdab in the header
> while the 13224 just has ffff ffff, no src PAN field.

That's the difference:
13224: src abcd:ffff dest abcd:fffff
raven: src abcd:ffff dest ffff:ffff

13224 has a src PAN, the dest PAN field has been compressed out
because the intra-PAN bit is set.

The router responds to the raven and not to the 13224.

> In the Raven I think all that is automatically handled by the radio chip.

There are comments several places in the code that say the PAN is FFFF
until the node is associated. But I can find no place in the code that
initializes the PAN FFFF.

Did you notice that the 13224 6lowpan field length is two bytes longer
than it should be? I believe that length error is caused by the
missing PAN field in the 802.15.4 header but I'm not sure.



>
> ----- Original Message -----
> From: "Jon Smirl" <jonsmirl at gmail.com>
> To: "Contiki developer mailing list"
> <contiki-developers at lists.sourceforge.net>; "mc1322x" <mc1322x at devl.org>
> Sent: Tuesday, November 17, 2009 5:14 PM
> Subject: [Contiki-developers] Broadcast PAN on Router solicitation
>
>
>> My Raven LCD sends a RS (router solicitation) with destination PAN
>> 0xFFFF and source PAN 0xABCD.
>> The 6lowpan data field is 30 byt
>> In attached raven pcap packet 12.
>> Same packet in expanded for is in packet 4.
>> This RS works.
>>
>> In my port to the mc13224 I can't get the RS packet right.
>> The equivalent undecoded packet is 4.
>> Source and destination PAN are both 0xABCD
>> The 6lowpan data field is 32 bytes.
>> The extra two bytes in the data field appear to be there because of
>> the missing destination PAN.
>> In the decoded packet (11) this two byte difference causes the unknown
>> option to be added.
>>
>> I can't figure out where in the code the destination PAN gets set to
>> 0xFFFF before association.  The bug is probably cause by some
>> structure needing a __packed__ attribute on ARM7. But I haven't been
>> able to locate where in the code the 0xFFFF is set.
>>
>> --
>> Jon Smirl
>> jonsmirl at gmail.com
>>
>
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-- 
Jon Smirl
jonsmirl at gmail.com