IESG Note
The following documents (RFC 4405, RFC 4406, RFC 4407, and RFC 4408)
are published simultaneously as Experimental RFCs, although there is
no general technical consensus and efforts to reconcile the two
approaches have failed. As such, these documents have not received
full IETF review and are published "AS-IS" to document the different
approaches as they were considered in the MARID working group.
The IESG takes no position about which approach is to be preferred
and cautions the reader that there are serious open issues for each
approach and concerns about using them in tandem. The IESG believes
that documenting the different approaches does less harm than not
documenting them.
...
The community is invited to observe the success or failure of the two
approaches during the two years following publication, in order that
a community consensus can be reached in the future.