Carsten, Forgive me, but I am not sure if this question was answered:
>>Is the NS+ARO message sent with multicast when I do registration the first time? You say: > Well, we don't need to resolve an address, so it should be unicast. This is under the assumption that I know where to register the very first time. Is it obvious that I know that? (how?) Thanks, Anders > -----Original Message----- > From: Carsten Bormann [mailto:[email protected]] > Sent: Wednesday, October 27, 2010 15:18 > To: Anders Brandt > Cc: [email protected] > Subject: Re: [6lowpan] ND: Sending NS+ARO message for the first time > > On Oct 27, 2010, at 14:56, Anders Brandt wrote: > > > Is the NS+ARO message sent with multicast when I do > registration the first time? > > One of the problems with specifying 6LoWPAN-ND as a delta to > 4861 is that it more than doubles the effective size of the > spec (6LoWPAN-ND is 59 pages, 4861 is 97 pages). 4861 says: > > 4.3. Neighbor Solicitation Message Format > > ... Neighbor Solicitations are multicast when the node needs > to resolve an address and unicast when the node seeks to verify the > reachability of a neighbor. > > Well, we don't need to resolve an address, so it should be unicast. > > I think the general rule is: > > -- Hosts only ever multicast RS (link-local, which is just > radio-range for Route-Over!) > -- Routers MAY multicast RAs, but generally unicast them > -- NS and NA (as well as DAR/DAC) are never multicast. > > I think it couldn't hurt to say this succinctly somewhere. > But the answer to your specific question is in there: > > 5.1. Forbidden Actions > > A host would never multicast a Neighbor Solicitation message. > > 5.2. Interface Initialization > > ...nobody multicasts Neighbor Solicitations in this type of network > > See also section 3: > The most important part of the optimizations is the > evolved host-to- > router interaction that allows for sleeping nodes and avoids using > multicast Neighbor Discovery messages except for the case of a host > finding an initial set of default routers, and redoing such > determination when that set of routers have become unreachable. > > But then there is some weird text in 6.5.5: > > Optionally Routers can use multicast Neighbor Solicitations as in > [RFC4861] to resolve each others link-layer addresses. > Thus Routers > MAY multicast Neighbor Solicitations for other routers, for example > as a result of receiving some routing protocol update. > Routers MUST > respond to multicast Neighbor Solicitations. This implies that > Routers MUST join the Solicited-node multicast addresses > as specified > in [RFC4861]. > > Rationale is not given and unknown to me; I don't think one > should implement either of these MUSTs. > > Gruesse, Carsten > > >>Hi >> >> >>> ND-14 version has been submitted after addressing the comments from working group LC. >> >> >> >>Having just managed to get through -13 I have a rather basic question: >> >>Is the NS+ARO message sent with multicast when I do registration the first time? >>In that case, what happens if this message reaches 50 different 6LRs within direct range? >>I suppose something prevents me from getting flooding? >> >>Thanks, >> Anders _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan
