IPv6 RA vs DHCPv6 - The chosen one?

Mohacsi Janos mohacsi at niif.hu
Fri Dec 23 06:03:34 UTC 2011

On Thu, 22 Dec 2011, Tomas Podermanski wrote:

> Hi,
> On 12/22/11 12:04 AM, Michael Sinatra wrote:
>> On 12/21/11 12:40, Ray Soucy wrote:
>>> I'm afraid you're about 10 years too late for this opinion to make
>>> much difference. ;-)
>>> We have been running IPv6 in production for several years (2008) as
>>> well (answering this email over IPv6 now, actually) yet I have
>>> completely different conclusions about the role of RA and DHCPv6.
>>> Weird.
>> And that's a very good reason not to deprecate SLAAC.  Tomas may
>> prefer DHCPv6, and he may provide reasons others may prefer DHCPv6.
>> But he hasn't provided justification for deprecating SLAAC.
> I am not against SLAAC. I am against the way how DHCPv6 & SLAAC works
> today. Today, SLAAC can not live without DHCPv6 and DHCPv6 can not live
> without SLAAC (RA). Second reason is that we have two
> protocols/techniques to do just the same thing. I prefer to have just
> ONE common autoconfiguration method as we have it in IPv4. Because
> DHCPv6 is more complex and SLAAC can provide only subset of DHCP
> functionality I personaly prefer DHCPv6.

This is your personal preference. Some has other personal preference.

>> Many of us have been working with IPv6 for years and have found SLAAC
>> to be quite useful.  The biggest benefit it provides, which Tomas did
>> not acknowledge, is the ability to autoconfigure hosts without running
>> a central server.  That said, I have also found DHCPv6 to be quite
>> useful.
> We have to use SLAAC as well because we do not have other choice. Not
> all operating systems supports DHCPv6 today. But we are not happy about
> it (problems with privacy extensions, security as I mentioned before).
> DHCPv6 do not have to be run on a central server. DHCPv6 can be
> implemented as a part of a router as well. It is common for DHCP(v4) an
> implementations for DHCPv6 are available today (eg. cisco
> http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-dhcp.html).

Similar configuration o routers:
- enabling ipv6 relay agent -> DHCPv6 configuration
- enabling router advertisment on interace -> SLAAC (some routers has to 

>> I also agree with Owen: Provide two complete solutions, and let
>> operators choose based on their needs.  That implies fixing DHCPv6 so
>> I don't have to go in and disable the autonomous flag on my routers
>> and run RAs just to get a default route.  But it also implies not
>> deprecating either SLAAC or DHCPv6.
> Although we have differed opinion whether we need one or two
> autoconfiguration protocols, I totally agree that "fixing" DHCPv6 is a
> really necessary step and It should have been done many years ago.
> Btw. not all people agree that DHCPv6 should be fixed in that way. There
> was a discussion in 2009 in dhcwg (thread available on:
> http://www.ietf.org/mail-archive/web/dhcwg/current/msg09715.html). The
> current draft (draft-ietf-mif-dhcpv6-route-option-03)  is the 3rd
> attempt to do it. In past, there were another two drafts trying to
> introduce route information into DHCPv6:
> draft-droms-dhc-dhcpv6-default-router-00, expired September 2009
> draft-dec-dhcpv6-route-option-05, expired  April 2011
> So I hope that this time we will have more luck :-)

I am also supporting this....

> Tomas

More information about the NANOG mailing list