Hello, One other question/comment:
Using the PAN-ID has the advantage of allowing the use of short-address zero. As RFC4944 is written now, it looks to me like if you didn't have the PAN-ID you would have an all zero 48-bit IID (which 4944 disallows). But I really don't have strong feelings about if it should be based on PAN-ID or not, I would like to see one way made "standard" though! Regards, -Colin -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Colin O'Flynn Sent: March 5, 2010 3:40 PM To: 'Richard Kelsey' Cc: [email protected] Subject: Re: [6lowpan] 6lowpan 16-bit PAN-ID Field Hello, Hmm, makes sense to me. Would it be possible to get a recommendation in hc-06 before WGLC, or where else would it make sense? As it's difficult to use hc06 with 16-bit addresses unless you decide on which way this will work. Regards, -Colin -----Original Message----- From: Richard Kelsey [mailto:[email protected]] Sent: March 5, 2010 2:39 PM To: Colin O'Flynn Cc: [email protected] Subject: Re: [6lowpan] 6lowpan 16-bit PAN-ID Field > From: "Colin O'Flynn" <[email protected]> > Date: Thu, 4 Mar 2010 22:59:22 -0000 > > RFC4944 has the quote: > > First, the left-most 32 bits are formed by concatenating 16 zero bits to the > 16-bit PAN ID (alternatively, if no PAN ID is known, 16 zero bits may be > used). This produces a 32-bit field as follows: > > How does a receiving node know if zero's have been used there to recreate > the IP addresses? Unless I'm missing something, this seems to be a ambiguous > case. It seems unlikely a node will know it's short address but not PAN-ID. I am not sure what to make of this either. The PAN ID may change if a PAN ID conflict is detected, in which case it would be a nuisance if all of the interface IDs had to change. To me, the only time where it might make sense to to use the PAN ID in the interface ID would be if a lowpan was spread across multiple PANs that did not coordinate 16-bit address assignment. Even in that case, it would be better to use a 'symbolic' PAN ID in the interface IDs, to avoid the need to change later. In a lowpan With only a single PAN ID it makes much more sense to use zeros and avoid problems if the PAN ID has to change. -Richard Kelsey _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan
