On Tue, Mar 15, 2016 at 3:11 AM, Michael Richardson <mcr@xxxxxxxxxxxx> wrote: > > Stefan Schmidt <stefan@xxxxxxxxxxxxxxx> 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. > > > Remis, Alex, Michael how does this sound. It would allow Remi to go ahead and > > do the work needed to get his driver and things for 15.4g mainline while the > > interop problem can get further discussed, speced and implemented. Whats your > > folks opinion on this? > > > > -- > ] Never tell me the odds! | ipv6 mesh networks [ > ] Michael Richardson, Sandelman Software Works | network architect [ > ] mcr@xxxxxxxxxxxx http://www.sandelman.ca/ | ruby on rails [ > -- Rémi Philippe - CTO Linqio -- To unsubscribe from this list: send the line "unsubscribe linux-wpan" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
