Re: [RRG] Consensus check: renumbering - missing dimension

["Christopher Morrow" <morrowc.lists@gmail.com>]

On 8/25/08, Brian E Carpenter <brian.e.carpenter@gmail.com> wrote:
> On 2008-08-26 09:28, Christopher Morrow wrote:
>  > On Sun, Aug 24, 2008 at 7:22 PM, Tony Li <tony.li@tony.li> wrote:
>  >>
>  >> |The reasoning is that IPv6 was designed that way, so why not
>  >> |use the feature if it proves to be useful, at least for small/medium
>  >> |sites.
>  >>
>  >>
>  >> Do folks really feel that stateless autoconfig is a significant step forward
>  >> vs. DHCP?  Current dual-stack site admins would be especially welcome to
>  >> opine.
>  >>
>  >
>  > stateless-autoconfig is entirely not sufficient for site admins to use
>  > in a 'renumbering' event. There are many items passed out in DHCP
>  > responses which are used by the end systems and not included in
>  > stateless-autoconfig. Existing practices account for these items via
>  > DHCP in a mostly centralized manner, without these items site-admins
>  > will be left with no option but to manually touch each device...
>  >
>  > Take a moderately large enterprise of 50k systems in a global setting,
>  > how long will it take to touch each of the 50k devices and change even
>  > the basics: dns-server, wins-servers, domainname  (assume you can not
>  > 'trust' the system owner/user to get this right, and assume you have
>  > limited helpdesk-staff).
>
>
> My memory is that back when stateless auto-config was conceived,
>  the main target was the "dentist's office" scenario, i.e.
>  basic Appletalk-like zeroconf sites. Unfortunately we still
>  have one hole in this area: no way to advertise a DNS server
>  address in RA messages. See RFC 4339.
>

Sure, today the model for 'dentist office' or 'home user' is that some
widget does dhcp, provides a bunch of info users can't possibly
understand (reliably) and it's entirely baked into the client and
'widget' OS. Conceptually it's not hugely different from
stateless-autoconf, except that it exists today and has existed for
10+years in a form that is useful.

>  I'm quite sure that larger sites with any kind of IT management
>  will need DHCPv6.
>

yup, and hopfully there will be a method to make sure that joe always
has address X sally Y and billy Z... DHCP does this today, not
everyone uses it, but it's a handy option to have. Having the same
address regardless of the NIC in the workstation.

>  But I don't see why that interacts with the multi-prefix issue.
>

I don't think it does... except that today in the ipv4/dhcp world most
end stations have only one address. I don't think most
network/system-admin folks in the new ipv6 world want to have
workstations with more than one globally routable address, I could be
mistaken, but in the situations where I was the network or system
admin I really only wanted one address per end host where regular
users were involved. (servers can and often are different beasts, also
lower in number...).

Keep in mind also that pushing the autoconf on the networking gear
means that  the 'network admin' now has to be cognizant of every wierd
little option the 'system admin' people want to tweak/test/use/demand.
It's been a challenge in places to get the 'network admin' to put in:
"ip helper 1.2.3.4" even when given the exact string to put into his
configuration. Asking for repeated and often changes is likely to
cause operational headaches.

(I think we talked about the mixing of job-jars before though...)

-Chris

>
>     Brian
>

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