6.2 Recommended Registration Policies

6.2. Recommended Registration Policies

For registration requests where a Designated Expert should be consulted, the IESG Area Director for Operations should appoint the Designated Expert.

For registration requests requiring Expert Review, the ietf-radius mailing list should be consulted.

Packet Type Codes have a range from 1 to 254, of which 1-5,11-13 have been allocated. Because a new Packet Type has considerable impact on interoperability, a new Packet Type Code requires Standards Action, and should be allocated starting at 14.

Attribute Types have a range from 1 to 255, and are the scarcest resource in RADIUS, thus must be allocated with care. Attributes 1-53,55,60-88,90-91 have been allocated, with 17 and 21 available for re-use. Attributes 17, 21, 54, 56-59, 89, 92-191 may be allocated following Expert Review, with Specification Required. Release of blocks of Attribute Types (more than 3 at a time for a given purpose) should require IETF Consensus. It is recommended that attributes 17 and 21 be used only after all others are exhausted.

Note that RADIUS defines a mechanism for Vendor-Specific extensions (Attribute 26) and the use of that should be encouraged instead of allocation of global attribute types, for functions specific only to one vendor's implementation of RADIUS, where no interoperability is deemed useful.

As stated in the "Attributes" section above:

  "[Attribute Type] Values 192-223 are reserved for experimental
  use, values 224-240 are reserved for implementation-specific use,
  and values 241-255 are reserved and should not be used."

Therefore Attribute values 192-240 are considered Private Use, and values 241-255 require Standards Action.

Certain attributes (for example, NAS-Port-Type) in RADIUS define a list of values to correspond with various meanings. There can be 4 billion (2^32) values for each attribute. Adding additional values to the list can be done on a First Come, First Served basis by the IANA.