On May 25, 2011, at 19:58, Ray Hunter wrote: > I've just read the RFC covering the (very interesting) mesh under / route > over mechanism used in 6LoWPAN > http://tools.ietf.org/html/draft-ietf-6lowpan-nd-16 . Very cool stuff.
Thanks! > Even there it was a requirement that all nodes taking part in the network > behave the same way. > > The applicability of this specification is limited to LoWPANs where all > > nodes on the subnet implement these optimizations in a homogeneous way. The idea here is that this draft updates RFC 4944 (the IP-over-foo for IEEE 802.15.4, usually referred to as 6LoWPAN) so that *all* nodes on a 6LoWPAN MUST implement 6LoWPAN-ND as opposed to ND-classic. > So if the point of this draft is really to limit multicast, then from an > operational perspective don't you want ALL nodes on a link to avoid using > multicast as much as possible? Yes, that is one of the reasons why we didn't try to tackle the theoretical possibility of interoperation between nodes implementing 6LoWPAN-ND and other nodes implementing ND-classic on 6LoWPANs, because even listening for multicast is very expensive for some nodes there. > So if the point of this draft is really to avoid operational problems with > STP thrashing, then from an operational perspective don't you want ALL nodes > on a link to avoid timing out too fast as much as possible? There is no STP in 6LoWPAN, so that isn't a consideration for this draft. Again, 6LoWPAN-ND is currently defined for non-Ethernet networks that are homogeneously 6LoWPAN-ND, i.e. 802.15.4 (and, most likely once their IP-over-foo documents stabilize, similar constrained networks such as BT-LE or DECT-ULE), However if people want to go ahead and do the work of adapting 6LoWPAN-ND (or some of its elements) to other networks, e.g., Ethernet/WiFi, then one would have to open that can of worms. Gruesse, Carsten -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
