On 11-aug-2007, at 0:28, Leino, Tammy wrote:
Has your working group considered adding this as a DHCPv6 option?
If the on-link router is not configured to transmit RAs, a DHCPv6
option advertising the default gateway would be helpful in
populating the routing table.
The problem with that would be that you either have to wait for some
time to be sure that there are no RAs, or you need to initiate DHCPv6
always immediately. The former leads to delays for the user, the
latter to additional network chatter which would be unnecessary in
most situations. Worse, the extra chatter is multicast, I'm again
stressing that multicasts take up inordinate amounts of bandwidth on
wifi networks.
So I don't think we should present NOT having RAs as a valid
configuration option. This way, we get to avoid the situations above.
If people want to configure hosts using DHCPv6 they should have
routers send out RAs with the M bit set and with no prefix information.
Note that currently, it's not possible to distribute default gateway
information through DHCPv6, so RAs would also have to be used for that.
(There is of course the consideration that at this time, very few
IPv6 implementations can configure an address through DHCPv6.)
Strange that a subnet size isn't included with the DHCPv6 address
assignment. I guess this means either configuring a /128 and rely on
router redirects to learn about directly attached neighbors, or use
RFC 3513 as your guideline and make it /64:
For all unicast addresses, except those that start with binary value
000, Interface IDs are required to be 64 bits long and to be
constructed in Modified EUI-64 format.
By the way, I would very much like to know who came up with that
requirement and why.
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