[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
DHCP, RA or both? was: Re: DHCP failures
On 3-aug-2007, at 13:16, Ralph Droms wrote:
The dhc WG has received a request to develop, on behalf of network
operators who have expressed the specific requirement that they do
not want the operation of their network to depend on RAs, new
options for DHCPv6 to pass prefix
Hm, didn't we already have that part?
and default router information to a host.
That would be new...
That information would allow a host to get all of its configuration
information from DHCPv6, obviating the use of RAs.
Will the IETF elite allow the standardization of these new options
to support this different mode of configuration or will those
network operators who would prefer to use only DHCPv6 be forced to
continue to use RAs?
That's not a question we can answer in isolation, it depends on our
collective view of the IPv6 provisioning architecture.
The reason that any way to configure DNS resolver addresses other
than through DHCPv6 was frustrated for so long was the argument that
we shouldn't have multiple mechanisms that do the same thing. Since
using RAs for configuring a host with one or more default routers has
been the standard for a decade, it seems that sticking to this
argument would make adding this capability to DHCPv6 impossible.
However, if we agree that DHCPv6 and RA based mechanisms suit
different users, it makes sense that we give both protocols the
capability to provide hosts with all essential configuration
(Cue discussion about what's essential and what isn't. In my opinion,
all non-essential information and/or information that's too large
should be handled by a layer of indirection in the form of a small
set of URLs where it can be downloaded.)
And when we've done all that, we need to figure out how to handle the
situation where different mechanisms supply conflicting information.
If DHCP and RAs are going to supply the same information, wouldn't it
make sense to make the option formats the same for easy parsing by an
implementation that handles both protocols, and for easier
synchronization between the capabilities of the two mechanisms?
Along the way somewhere someone will have to figure out how the DHCP
server learns the router's address, as this tends to be neither very
predictable nor memorable in current implementations and mistakes
have been known to happen with IPv4 DHCP.