Hi Joseph: Ping is a weird thing since you can force anything and some things just won't work.
I'd rather stick to SAS (RFC3484) and standard IPv6 behavior which was good enough for RFC 3775 and family (3963, 5555, ...). The link local of the lowpan device does not have the scope to reach the backbone. So that address is not visible to the node on the backbone and there is no way the backbone device can know it. So the node on the backbone should only resolve the global address of device. For that address, SAS rules will cause the node to source with the same scope (global) longest match (same prefix). Pascal >-----Original Message----- >From: [email protected] [mailto:[email protected]] On Behalf Of Reddy, Joseph >Sent: mercredi 18 novembre 2009 02:26 >To: [email protected] >Subject: Re: [6lowpan] Thoughts on draft-ietf-6lowpan-nd-07 > > > >Hi Pascal, > >The proxy-ND that you described from the draft may not always work....consider the case where a >backbone node attempts to "ping6" a 6lowpan node. > >To the backbone node, the 6lowpan devices appears as "on-link" since the ER responds with NS on behalf >of the 6lowpan device. This will cause the backbone node to communicate with the 6lowpan device using >its link-local address as the source address. Then the 6lowpan device has no way to respond back to >the backbone node since it only knows the link local address and not the global address of the >backbone node ( unless 6lowpan routers can forward packets with link-local destinations ). Did I miss >something here ? > > >-Regards, Joseph > > >------------------------------ > >Date: Tue, 17 Nov 2009 18:36:37 +0100 >From: "Pascal Thubert (pthubert)" <[email protected]> >Subject: Re: [6lowpan] Thoughts on draft-ietf-6lowpan-nd-07 >To: "Colin O'Flynn" <[email protected]>, "Carsten Bormann" > <[email protected]>, "Alexandru Petrescu" <[email protected]> >Cc: 6lowpan <[email protected]> >Message-ID: > <[email protected]> >Content-Type: text/plain; charset="us-ascii" > >Hi Colin: > >I think you're describing the draft. Basically the edge router does proxy-ND over the backbone. >So if a node on the backbone looks up a 6LoWPAN device, the edge router answers NS with NA on behalf >of the device. >So the node sends packets via the edge router. The edge router forwards back to the device over the >lowpan. >As you figures, this is why the device needs to periodically maintain the binding with the edge >router. > >This is somewhat similar to mobile IPv6 though there's no tunnel. > >Pascal >_______________________________________________ >6lowpan mailing list >[email protected] >https://www.ietf.org/mailman/listinfo/6lowpan _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan
