Re: 802.15.4G support?

[Stefan Schmidt <stefan@osg.samsung.com>]

Hello.

On 15/03/16 06:19, Remi Philippe wrote:
> On Tue, Mar 15, 2016 at 3:11 AM, Michael Richardson <mcr@sandelman.ca> wrote:
>> Stefan Schmidt <stefan@osg.samsung.com> wrote:
>>      > 2) If the 802.15.4g node uses a SUN PHY with a 2047 byte MTU we can run into
>>      > trouble with normal nodes only able to handle 127. So far there is nothing
>>      > specified to handle this case. Michael is proposing to use 6lo ND for this
>>      > and record the MTU value for this neighbour in the l2 nd cache. Something
>>      > that would certainly work but would need specing and implementing. I see this
>>      > as a mid term goal we want to have. Anyone going to work on this?
>>
>> It's not even clear to me that ND can do this.
>> I still propose that we want to have a space in the l2 or l3 ND cache for
>> this info.  It could well go in the L3 cache because it is really a statement
>> about how the 6lowpan layer should fragment.
>>
>>      > 3) Until 2) is done I would suggest we add a config option "802.15.4g with
>>      > SUN PHY" which will change the hardcoded MTU from 127 to 2047 and will thus
>>      > only work for a 15.g with SUN PHY only network. No interop as we have no way
>>      > of knowing. The option would be disabled by default and the help text needs
>>      > to mention the drawbacks. Once we have 2) in place we can remove this.
>>
>> Couldn't we use "ifconfig blah0 mtu 2047"?
> Maybe we should do both, have a flag to specify the PHY type as the
> PHY header is slightly different in15.4g MR-FSK to support for mode
> switch, data whitening... it needs to support 2 octets header (page 52
> of the 802.15.4g-2012 spec) it can also lock the max MTU supported for
> the media. And allow to change the MTU from command line.
>

Did you move on with this? If you ahve any patches let us know. We are 
happily going to review them.

regards
Stefan Schmidt