Re: [Autoconf] Using DHCPv6 without link-local? Support only EUI-64interfaces?

Hi Teco,

> -----Original Message-----
> From: Teco Boot [mailto:teco@inf-net.nl]
> Sent: Saturday, July 31, 2010 6:57 AM
> To: Templin, Fred L
> Cc: autoconf@ietf.org autoconf@ietf.org
> Subject: Re: [Autoconf] Using DHCPv6 without link-local? Support only EUI-64interfaces?
> 
> Fred,
> 
> Do you mean DHCP relay can be used on a node, that request an address
> for itself?

I mean that the client function on a node sends a DHCP
request that is intercepted by a relay function on that
same node. The relay forwards the DHCP request to a DHCP
server, which then sends a reply via the same relay. The
relay then forwards the reply to the client on the same
node, and the client does the appropriate thing.

> I think it could work this way:
> 1) Node queries with link-local to All_DHCP_Relay_Agents_and_Servers.
> 2a) Node acts as also relay and queries with ULA (site-local) to All_DHCP_Servers.
> 2b) If node is provisioned with DHCP server unicast address, it could use that
>     instead of All_DHCP_Servers.
> I think this is in line with your RFC 5558.
> 
> Drawback of 1: it can result in high number of relayed DHCP packets, in case
> of many neighbors.
> Another drawback of 1: there is a timeout delay when there is no relay or server
> at one hop.

Right, but that's not the scenario I was describing.

> For 2a: the network needs multicast support. Could be SMF.

Ack.

> For both 2a and 2b: a temporally used unicast address must be routable. So this
> DHCP mechanism can only be used as a second step, moving from the self-generated
> address to a centrally managed address.

That's what VET is essentially saying, yes.

Thanks - Fred
fred.l.templin@boeing.com

> Teco
> 
> 
> 
> 
> Op 30 jul 2010, om 17:40 heeft Templin, Fred L het volgende geschreven:
> 
> > Teco,
> >
> >> -----Original Message-----
> >> From: autoconf-bounces@ietf.org [mailto:autoconf-bounces@ietf.org] On Behalf Of Teco Boot
> >> Sent: Friday, July 30, 2010 4:58 AM
> >> To: autoconf@ietf.org autoconf@ietf.org
> >> Subject: [Autoconf] Using DHCPv6 without link-local? Support only EUI-64interfaces?
> >>
> >> RFC3315:
> >>   ...     The client
> >>   MUST use a link-local address assigned to the interface for which it
> >>   is requesting configuration information as the source address in the
> >>   header of the IP datagram.
> >>
> >> Question: can we get around a MUST in a standards track RFC?
> >> I don't think so.
> >
> > If the MANET router only behaves as a client on an internal
> > link (e.g., a loopback) but behaves as a relay on its MANET
> > interfaces, then link-locals need not be exposed for DHCPv6
> > purposes. There are other reasons why link-locals might need
> > to be considered for MANETs, but I'm not sure this is one
> > of them.
> >
> > Fred
> > fred.l.templin@boeing.com
> >
> >> The to be posted proposed text for to be RFC5889 would say that if link-locals are used, there are
> >> potential problems when using other than modified EUI-64 IIDs, and therefore must be based on
> >> modified EUI-64 IIDs.
> >>
> >> Second question, on first item in charter: do we limit ourself to MANET routers that has modified
> >> EUI-64 link-locals?
> >> I think: better think twice.
> >>
> >> Opinions?
> >>
> >> Teco.
> >>
> >>
> >> _______________________________________________
> >> Autoconf mailing list
> >> Autoconf@ietf.org
> >> https://www.ietf.org/mailman/listinfo/autoconf