I was looking over the Simple DNA draft, and had some questions:
Section 3.3 says:
All Router Solicitations and unicast Neighbour Solicitations sent for
DNA purposes while addresses are in optimistic state SHOULD include
the Tentative Option [4].
I do not believe that DNAv6 implementations should be required to support
Optimistic DAD. Prior to completion of DNAv6, a candidate address can be
considered Deprecated; after successful completion, it can be promoted to
Preferred.
Why should the Tentative Option be set in a Unicast Neighbor Solicitation?
After all, this is sent to the unicast IPv6 and MAC address of the router,
not to multicast IPv6/MAC addresses. Therefore, there is no risk of
cache pollution. Therefore why not establish the neighbor cache entry
immediately so that incoming packets can be received? To facilitate
this, the unicast NS packet should be sourced from the candidate address.
Section 3.4 says:
The Router Solicitation is sent to the All-routers
multicast address containing one of the host's optimistic unicast
source address [2][5]. If the host is in possession of more than one
valid IPv6 address, it MUST send only one router solicitation using
any one of its valid IPv6 addresses as the source address.
Why is one of the candidate addresses chosen as the source? Since the router
MAY respond to this address with a unicast RA, doesn't this risk loss of the
RA if the candidate address chosen isn't appropriate for the network?
Wouldn't it make more sense for the source to be the unspecified address?
Also, I'd suggest that the RS *not* contain a SLLAO, so as to avoid
cache pollution.
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