IANA
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... the proposed usage has been adequately reviewed by the broader
community. Consequently, some number spaces specify that IANA only
make assignments in cases where there is strong community support for
a proposed protocol. For example, values out of some name spaces are
...
... be needed that won't collide with an existing or future usage.
One approach is to allow IANA to make temporary assignments for such
purposes. The idea is that a protocol value can be assigned to allow
...
... protocol value can be assigned to allow
experimentation, but after the experiment ends, the number would be
returned to IANA. There are several drawbacks to this approach,
however. First, experience has shown that it can be difficult to
reclaim numbers once assigned. For example, contact information
...
... protocol
numbers for experimentation. Such reservations can be made through
an explicit reservation in an IANA Considerations section.
The exact number of values to reserve for experimentation will depend
...
... IANA Considerations ...
... IETF
Standards Action per [RFC2780]. For the purposes of experimentation
and testing, IANA has assigned the two values 253 and 254 for this
purpose. These values have been allocated from the upper end of the
available number space ...
... Bradner, S. and V. Paxson, "IANA Allocation Guidelines For Values In the Internet Protocol and Related Headers", BCP ...
... Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. ...