Subject: Re: [dhcwg] questions about dhcpv6-28

From: JINMEI Tatuya / 神明達哉<[email-masked]>
Date: Tue, 04 Feb 2003 19:20:19 +0900

(In the followings, I folded some long lines)

>>>>> On Tue, 28 Jan 2003 12:42:33 -0600, 
>>>>> "Bernie Volz (EUD)" <[email-masked]> said:

>> Ralph pointed out to me the possibility of some "magic" between a
>> primary server and a backup server, which allows those servers to be
>> synchronized in real time.  I'm not sure how this is realistic,
>> either, but I'd personally prefer to keep the possibility.

> For DHCPv6 there seems to me a better way to handle things like failover?

> The two standard mechanisms would be:
> 1. Failover like protocol between the two servers
> 2. Redundant backend database

> But, with the large IPv6 addresses, there is another way which I
> think is even better and requires no communication between
> "redundant" servers (well, there is the configuration issues but
> there is no need or minimal need for ongoing communication). The
> idea is as follows:

(snip)

> I wonder whether the DHC WG might take this on - to specify how
> redundant DHCPv6 services could or should be built? I think it will
> be easier than the DHCPv4 failover work and may not require any
> protocol - just a way of working? But, then perhaps this is simply
> left to the server implementers to decide how best to work and
> interoperability between several vendors is not required?

Thanks for the detailed analysis.  I, for one, think the mechanism to
provide the redundancy among multiple servers can be out of scope for
the dhc wg (at least for now).

Going back to the original question, what should the server do when it
receives a Rebind containing an IA for which the receiving server does
not have a binding?

Option 1 (from Ralph): the server should ignore the Rebind unless it
has an "explicit" knowledge that the binding has been invalidated.

Option 2 (from Bernie): the server should return a Reply with
NoBinding anyway, and let the client choose the reaction based on the
Server Identifier that provided the IA.

As I said before, I prefer Option 1.

					JINMEI, Tatuya
					Communication Platform Lab.
					Corporate R&D Center, Toshiba Corp.
					[email-masked]
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---

From: Ralph Droms <[email-masked]>
Date: Wed, 05 Feb 2003 09:25:44 -0500

I agree that we should consider the issue of an inter-server protocol to be 
out of scope for now.  We have experience in designing DHCPv4 so that the 
client-server protocol is independent of the server-server protocol.

I would prefer option 1 - the server ignores a Rebind message for which it 
has no explicit information.

- Ralph

At 07:20 PM 2/4/2003 +0900, JINMEI Tatuya /