Subject: Re: Re: [dhcwg] Operational problem caused by inconsistent RA M and Oflags

From: HYUN WOOK CHA <[email-masked]>
Date: Mon, 07 Jan 2008 23:36:25 +0000 (GMT)

Dear Thomas,

Please see my inline comments.

> If no DHCP server is available, clients will back off and retry slowly
> (I assume). So, this is not a serious problem. Perhaps not ideal, but
> not a serious problem.
Yes, it might not be a serious problem. What I want to point out is not bandwidth consumption. As long as I understand rfc2462, this result is not expected for a administrator because he(she) is notifying that a DHCPv6 server is not available by sending RA with M flag set to 0 and the only condition where DHCPv6 clients may start discovering DHCPv6 servers is that receiving RA with M flag set to 1(previously set to 0) and a client is not running.  

> IMO, infinite lease times are a Bad Idea. If we had to do it over
> again, I'd probably argue the protocol should not support them. In
> order for things to work "properly" in practice, you need to have
> routers and DHCP servers that function correctly. It just doesn't make
> sense (generally) any other way. So we shouldn't be over engineering a
> case where a client has a working network, but the routers or DHCP
> servers are not working (for long periods of time, like hours and
> days).

I hope that DHCPv6 authors will take this argument.

Thank you,

Joseph Hyunwook Cha

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From: Ted Lemon <[email-masked]>
Date: Mon, 7 Jan 2008 17:43:40 -0700

> I hope that DHCPv6 authors will take this argument.

For what it's worth, I'm definitely in favor of deprecating infinite  
address lifetimes, although that does beg the question: how long is  
too long?   Also, where did that requirement come from - did it  
originate with the DHCPv6 spec, or is it an underlying requirement  
from the IPv6 specs?   I don't remember the discussion about this  
anymore.

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From: Thomas Narten <[email-masked]>
Date: Mon, 07 Jan 2008 20:02:38 -0500

> from the IPv6 specs?   I don't remember the discussion about this  

This was an IPv6 decision. RAs also have an infinite lifetime value
for the prefixes contained in PIOs.

No doubt, there would be some who argue that they should be left in.

Too late to do this IMO. The train has left the station and not worth
revisiting.

Thomas