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

Teco Boot <teco@inf-net.nl> Wed, 04 August 2010 06:20 UTC

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From: Teco Boot <teco@inf-net.nl>
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Date: Wed, 4 Aug 2010 08:21:11 +0200
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To: Ulrich Herberg <ulrich@herberg.name>
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Subject: Re: [Autoconf] Using DHCPv6 without link-local? Support only EUI-64interfaces?
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Op 3 aug 2010, om 10:28 heeft Ulrich Herberg het volgende geschreven:

> Hi Henning,
> 
> On Tue, Aug 3, 2010 at 7:25 AM, Henning Rogge
> <henning.rogge@fkie.fraunhofer.de> wrote:
>> Hello,
>> 
>> is there a reason why we cannot place an DHCPv6-relay on every node for its
>> neighbors ? Each node requesting an address/prefix will send out an IP
>> datagram with an anycast destination an a linklocal source, which will be
>> forwarded by its neighbors (with a unicast) to the DHCPv6-server.
> 
> Sure, that works. DHCP clients would typically send their messages to
> the All_DHCP_Relay_Agents_and_Servers multicast address. However, that
> necessitates the use of a unicast routing protocol, because the relay
> has to have a route towards the DHCP server. The question is, do we
> want to depend on that? I think we should also have a running autoconf
> mechanism in cases when there is no unicast routing protocol in place.

This is the 2b scenario.
A problem is that all neighbors relay the DHCP request. In a dense network,
(to) many neighbors will relay. One can think of a backpressure mechanism. 
Another problem is the discovery of the DHCP server(s). Easy to solve,
solutions are around (BRDP is just one of them). But in many solutions,
the MANET protocol is adjusted for service discovery support. (BRDP is not
a MANET protocol, it is an RA extension).
I don't think the need for a routing protocol for forwarding packages is a
problem. There are no functional MANETs without. 


Teco.