On Oct 21, 2010, at 16:48, Margaret Wasserman wrote: [in her RPL review about RPL's various forms of encapsulation:]
> (1) 6lowpan, > which is the only link type I know of that RPL has been > run over to date, has an MTU of 1280, not 1280+++ as > required by the 6lowpan spec, (I think you meant 6man/RPL spec at the end.) Indeed. However, the number 1280 is somewhat arbitrary for 6LoWPAN, as we have to piece L3 packets together out of ~100 byte L2 fragments anyway. The actual adaptation layer format is fine with any MTU up to 2047; we just chose the lowest MTU possible*) in IPv6 as a concession for constrained nodes (and 1280 still is quite heavy for some of them). So it is not unconceivable that 6LoWPAN could help RPL routers by adding a mode that extends the MTU somewhat. Of course, the details of such an extension would need to be defined, preferably in conjunction with the rest of the 6man/RPL stack. Gruesse, Carsten *) The assumption was that, as a stub network, a 6LoWPAN would not need to support tunneling. That assumption may have been wrong. _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan
