Hi Peter,
Your guess is correct - GP is the address autoconfigured with the global prefix (from the RA) based on the 16-bit MAC address. This autoconfiguration is specified in RFC4944, section 6. Hc-08 changes that slightly though for the 16-bit address, see section 3.2.2. Regards, -Colin From: [email protected] [mailto:[email protected]] On Behalf Of Peter Bigot Sent: July 26, 2010 5:17 PM To: Zach Shelby Cc: 6lowpan 6lowpan Subject: Re: [6lowpan] #87: GP16 as source address in initial NS This thread refers to "GP16" from a Zigbee Interop document, and I infer it's probably a global-scope IPv6 address derived from a 16-bit 802.15.4 short address, but how the derivation is done is not clear. The term does not appear in 6lowpan-nd except in a comment in -11 that refers to this thread; nor is it in RFC4944 or 6lowpan-hc-08. If it's a Zigbee concept, could somebody translate it into IETF-speak, or at least suggest where those of us privileged to access the Zigbee Alliance docs might find the referenced interop report? Thanks. Peter On Sun, Jul 25, 2010 at 3:59 PM, Zach Shelby <[email protected]> wrote: On Jul 19, 2010, at 4:54 PM, Robert Cragie wrote: > I'm still confused by this. Earlier, Zach said that in fact we should not be using GP16 in the src IP address of the NS. I totally agree. Sorry, that was a temporary brain-short (which I corrected). In nd-10 the NS src IP address must be the address being registered, and the SLLAO the LLA corresponding to that address. In the case of ZigBee IP, that would be the GP16 and the 16-bit MAC address. The main reason for using the address being registered as the NS src IP address is related to security. We would like to preserve compatibility with SeND for more general applicability of this mechanism in the future. I am not totally caught up on the 6lowpan and ZigBee IP mailing lists (just came back from vacation yesterday), but to throw a few possible options out here: a. Do things as in nd-10 and require more specialized code for this, this was the conclusion the authors came when closing ticket #87. Most 6lowpan implementations are specialized stacks anyways - is this really an issue? b. Move the address being registered to the ARO and add a flag (breaking SeND compatibility). c. Allow use of the 64-bit MAC address in the SLLAO of the NS even when the IP src address is a tentative GP16. This doesn't really solve the resolution problem worrying Dario and Robert though. I will add a bullet point about this to the ND presentation for the WG meeting tomorrow. Zach -- Zach Shelby, Chief Nerd, Sensinode Ltd. http://zachshelby.org - My blog "On the Internet of Things" http://6lowpan.net - My book "6LoWPAN: The Wireless Embedded Internet" Mobile: +358 40 7796297 _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan
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