Re: [v6ops] New Version Notification for draft-yourtchenko-ra-dhcpv6-comparison-00.txt (fwd)

[Owen DeLong <[e-mail]>]

On Dec 8, 2013, at 11:22 , Brian E Carpenter <[e-mail]> wrote:

> On 08/12/2013 19:40, Owen DeLong wrote:
>> On Dec 7, 2013, at 22:25 , Andrew Yourtchenko <[e-mail]> wrote:
> 
> ...
>>> I think you nailed it here: With RA you *discover* the routers available on the link, with DHCP in legacy IP, you *configure* them.
>> 
>> No, with DHCP, you discovered what some remote host rumored them to be.
> 
> I don't think we should be having this argument. We should be
> trying to write down objectively the type of scenarios where
> DHCPv6 is applicable, the type of scenarios where RA-only is
> applicable, and the type of scenarios where both (simultaneously)
> are applicable.
> 
> There's no right or wrong answer here.
> 
>   Brian

In IPv6, as I read the RFCs, there's no valid way for a host to know that it is supposed to get information from a DHCPv6 server unless it receives an RA with the M and/or O bits set.

As such, the options are not DHCPv6 only, RA-only, and Both, but, RA-only and Both.

The scenarios where RA-Only make sense are any scenario where you do not need greater control of the client configuration than Prefix information, routing information, and DNS resolver addresses and search strings.

In any scenario where you need to supply the host with more configuration information on a dynamic basis, DHCPv6 is also required.

Also, if you want dynamic DNS updates, deterministic assigned suffixes, etc., these fall into the DHCPv6 realm.

It's really as simple as that as near as I can tell.

If you want to run without RAs, then you are into the realm of static configuration. I, personally, do not see this as a problem.

Owen