IPv6 Deployment for the LAN

Owen DeLong owen at delong.com
Wed Oct 21 20:48:42 UTC 2009


On Oct 21, 2009, at 1:08 PM, Iljitsch van Beijnum wrote:

> On 21 okt 2009, at 21:55, Owen DeLong wrote:
>
>> However, making it available as an option in DHCPv6 allows the end- 
>> user/operator
>> to choose the technology that fits their needs best. I do not know  
>> why you are so
>> determined to prevent this choice at the operator level.
>
> For the same reason that we don't let the kids play with the  
> powertools: giving them what they want here just makes everything  
> end in tears.
>
> If people want to run DHCPv6, fine, we're all adults. If they want  
> to go to the IETF and fix what's wrong with DHCPv6, so much the  
> better. But taking the information from the place where we can make  
> sure it's correct and putting it in a place where we can only guess  
> so we break the network regularly is A VERY BAD IDEA.

You're incorporating a lot of assertions into your statement there.

The assumption that the router "knows" it is correct for every host on  
a given
LAN simply does not map to reality deployed today.

DHCPv4 router assignments don't end in tears for the most part today,  
and,
I don't think that DHCPv6 router assignment would be any more broken  
than
the RA system.  In many cases, it will be less broken.

The assumption that all routers of a given priority are equal for all  
hosts
on a given LAN also doesn't quite work out.  DHCPv4 allows me to have
multiple sets of VRRP addresses and balance my outbound routing from
large LAN segments (imagine a /22 full of 10-g servers pushing ~6G
each into a set of routers... Because they're a rendering farm, and the
software is somewhat brain-dead, they need to be in the same broadcast
domain.) (Yes, I know that broadcast goes away in IPv6, but, this can
just as easily be a link-local multicast).

With DHCPv4, I can assign different VRRP groups to the systems (with
different IPv4 unicast addresses) based either on mac-addresses, or
whatever other criteria I choose.

Please explain to me how I can achieve this functionality in RA/SLAAC
or stop pushing to prevent it from being available in DHCPv6.

Seriously, we're all adults.  So treating us like children and taking  
away
the power tools is not appreciated.

Owen





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