Subject: RE: NUD and solicitated Router Advertisement ?

From: "Soliman Hesham" <[email-masked]>
Date: Mon, 16 Aug 2004 13:26:31 -0400

> ----- Original Message ----- 
 > From: <JINMEI Tatuya / $B?@L@C#:H (B 
 > <[email-masked]>)>
 > To: "Grubmair Peter" <[email-masked]>
 > Cc: "IPV6 IETF (E-mail)" <[email-masked]>
 > Sent: Monday, August 16, 2004 10:57 AM
 > Subject: Re: NUD and solicitated Router Advertisement ?
 > 
 > 
 > > >>>>> On Mon, 2 Aug 2004 12:24:11 +0200 ,
 > > >>>>> Grubmair Peter <[email-masked]> said:
 > >
 > > > In page 49, chapter 4.3.4 of draft-soliman-ipv6-2461-bis-01.txt
 > > > it is stated that after reception of Router Advertisement, which
 > > > contains a source link-layer address option, a new
 > > > neighbor cache entry SHOULD be created.
 > > > The state of this new cache entry shall be STALE.
 > > > But to my mind, if the destination address of
 > > > Router advertisement packet is a unicast address of
 > > > the interface, I can set state to REACHABLE.
 > > > This is because this router advertisement must be a
 > > > response to my router solicitation.
 > >
 > > This is not correct, since the router advertisement may be an
 > > unsolicited one or a solicited one but in response to other router
 > > solicitations (and your solicitation may have been lost).  So we
 > > cannot set the state to REACHABLE in this case.
 > >
 > 
 > I think that Unsolicted RA *ALWAYS* sent to "All Nodes 
 > Multicast Address -
 > ff02::1".
 > 
 > [PS : Solicited RA may also be sent to All Nodes, in case 
 > unsolicited RA is
 > just scheduled
 > after the reception of RS]
 > 
 > Conclusions:
 > 1) All Unsolicited RAs are multicast destined but vice versa 
 > does not hold
 > good :)
 > 2) All unicast RAs are solicited.
 > 
 > Am I right ?

=> Yes I think you are. BTW, the right draft to look
at now is draft-ietf-ipv6-2461bis-00.

Just to make sure I/we understand this optimisation clearly, 
I guess the purpose here is to eliminate NUD. The STALE
state will not delay packet delivery, so the gain here is 
eliminating the NUD exchange. 

I don't see a problem with this. If someone else sees 
any issues here please let us know. 

Hesham

 > 
 > Thank you,
 > O.L.N. Rao
 > 
 > 
 > > JINMEI, Tatuya
 > > Communication Platform Lab.
 > > Corporate R&D Center, Toshiba Corp.
 > > [email-masked]
 > >
 > > 
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