Pascal Thubert (pthubert) a écrit :
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.
I don't understand why the ER needs to do proxy ND on behalf of a
6LoWPAN node.
If a node on the backbone wants to talk to a 6LoWPAN node then it talks
to its default route which will ICMP Redirect towards ER, and then pure
NS/NA about the ER.
No need for ER to do proxy ND for 6LoWPAN nodes for this to work.
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.
Moreover, in Mobile IPv6 the nodes are not behind the HA - they simply
are gone and away. Whereas here your nodes _are_ behind the ER yet the
ER proxies for them - why the troubling noise and clutter?
Alex
Pascal
-----Original Message-----
From: Colin O'Flynn [mailto:[email protected]]
Sent: mardi 17 novembre 2009 17:55
To: 'Carsten Bormann'; 'Alexandru Petrescu'
Cc: Pascal Thubert (pthubert); Ralph Droms (rdroms); '6lowpan'
Subject: RE: [6lowpan] Thoughts on draft-ietf-6lowpan-nd-07
Hello,
The backbone is supposed to be an Ethernet or a similar high-capacity
link, so it should have little problem with that load.
Agreed.
the idea was to enable other nodes to live on the backbone link and ?
communicate with the 6lowpan nodes without requiring any
6lowpan-specific
code. Those other nodes will speak 4861 only.
Is the NA/NS solely to exchange information about the whiteboard
between the
ERs?
If so, they could perform a proxy-ND to respond to NS directed at nodes
on
the 6LoWPAN.
Then some other method to keep whiteboards up to date could be used.
I'm not advocating such a thing, just saying if the clutter of 4861
traffic
on the Ethernet side of the ER was an issue I would think there would
be
other solutions!
Regards,
-Colin
-----Original Message-----
From: Carsten Bormann [mailto:[email protected]]
Sent: November 17, 2009 4:49 PM
To: Alexandru Petrescu
Cc: Colin O'Flynn; 'Pascal Thubert (pthubert)'; 'Ralph Droms (rdroms)';
'6lowpan'
Subject: Re: [6lowpan] Thoughts on draft-ietf-6lowpan-nd-07
On Nov 17, 2009, at 16:08, Alexandru Petrescu wrote:
Is it efficient for the Edge Router to send a myriad of Neighbor
Advertisement messages (which are addressed to a link-layer multicast
address, and a L3 multicast address) on the backbone?
Well, we try to be fully 4861-compliant on the backbone.
The backbone is supposed to be an Ethernet or a similar high-capacity
link,
so it should have little problem with that load.
Why cluttering the backbone?
Because that's what 4861 does to you? :-)
Of course, the ERs could speak a different protocol between themselves,
but
the idea was to enable other nodes to live on the backbone link and
communicate with the 6lowpan nodes without requiring any
6lowpan-specific
code. Those other nodes will speak 4861 only.
Gruesse, Carsten
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