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,  
I don't think that DHCPv6 router assignment would be any more broken  
the RA system.  In many cases, it will be less broken.

The assumption that all routers of a given priority are equal for all  
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  
the power tools is not appreciated.


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