RFC8748

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Internet Engineering Task Force (IETF) R. Carney Request for Comments: 8748 GoDaddy Inc. Category: Standards Track G. Brown ISSN: 2070-1721 CentralNic Group plc

                                                              J. Frakes
                                                             March 2020


Registry Fee Extension for the Extensible Provisioning Protocol (EPP)

Abstract

  Given the expansion of the DNS namespace and the proliferation of
  novel business models, it is desirable to provide a method for
  Extensible Provisioning Protocol (EPP) clients to query EPP servers
  for the fees and credits associated with various billable
  transactions and provide expected fees and credits for certain
  commands and objects.  This document describes an EPP extension
  mapping for registry fees.

Status of This Memo

  This is an Internet Standards Track document.
  This document is a product of the Internet Engineering Task Force
  (IETF).  It represents the consensus of the IETF community.  It has
  received public review and has been approved for publication by the
  Internet Engineering Steering Group (IESG).  Further information on
  Internet Standards is available in Section 2 of RFC 7841.
  Information about the current status of this document, any errata,
  and how to provide feedback on it may be obtained at
  https://www.rfc-editor.org/info/rfc8748.

Copyright Notice

  Copyright (c) 2020 IETF Trust and the persons identified as the
  document authors.  All rights reserved.
  This document is subject to BCP 78 and the IETF Trust's Legal
  Provisions Relating to IETF Documents
  (https://trustee.ietf.org/license-info) in effect on the date of
  publication of this document.  Please review these documents
  carefully, as they describe your rights and restrictions with respect
  to this document.  Code Components extracted from this document must
  include Simplified BSD License text as described in Section 4.e of
  the Trust Legal Provisions and are provided without warranty as
  described in the Simplified BSD License.

Table of Contents

  1.  Introduction
    1.1.  Conventions Used in This Document
  2.  Migrating to Newer Versions of This Extension
  3.  Extension Elements
    3.1.  Client Commands
    3.2.  Currency Codes
    3.3.  Validity Periods
    3.4.  Fees and Credits
      3.4.1.  Refunds
      3.4.2.  Grace Periods
      3.4.3.  Correlation between Refundability and Grace Periods
      3.4.4.  Applicability
    3.5.  Account Balance
    3.6.  Credit Limit
    3.7.  Classification of Objects
    3.8.  "Phase" and "Subphase" Attributes
    3.9.  Reason
  4.  Server Handling of Fee Information
  5.  EPP Command Mapping
    5.1.  EPP Query Commands
      5.1.1.  EPP <check> Command
      5.1.2.  EPP Transfer Query Command
    5.2.  EPP Transform Commands
      5.2.1.  EPP <create> Command
      5.2.2.  EPP <delete> Command
      5.2.3.  EPP <renew> Command
      5.2.4.  EPP <transfer> Command
      5.2.5.  EPP <update> Command
  6.  Formal Syntax
    6.1.  Fee Extension Schema
  7.  Security Considerations
  8.  IANA Considerations
    8.1.  XML Namespace
    8.2.  EPP Extension Registry
  9.  References
    9.1.  Normative References
    9.2.  Informative References
  Acknowledgements
  Authors' Addresses

1. Introduction

  Historically, domain name registries have applied a simple fee
  structure for billable transactions, namely a basic unit price
  applied to domain <create>, <renew>, <transfer>, and Redemption Grace
  Period (RGP) [RFC3915] restore commands.  Given the relatively small
  number of EPP servers to which EPP clients have been required to
  connect, it has generally been the case that client operators have
  been able to obtain details of these fees out of band by contacting
  the server operators.
  Given the expansion of the DNS namespace and the proliferation of
  novel business models, it is desirable to provide a method for EPP
  clients to query EPP servers for the fees and credits associated with
  various billable transactions and certain commands and specific
  objects.
  This document describes an extension mapping for version 1.0 of the
  Extensible Provisioning Protocol (EPP) [RFC5730].  This EPP mapping
  provides a mechanism by which EPP clients may query the fees and
  credits associated with various billable transactions and obtain
  their current account balance.

1.1. Conventions Used in This Document

  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
  "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
  "OPTIONAL" in this document are to be interpreted as described in
  BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
  capitals, as shown here.
  XML is case sensitive.  Unless stated otherwise, the XML
  specifications and examples provided in this document MUST be
  interpreted in the character case presented in order to develop a
  conforming implementation.
  "fee" is used as an abbreviation for "urn:ietf:params:xml:ns:epp:fee-
  1.0".  The XML namespace prefix "fee" is used, but implementations
  MUST NOT depend on it and instead employ a proper namespace-aware XML
  parser and serializer to interpret and output the XML documents.
  In the examples, "C:" represents lines sent by a protocol client, and
  "S:" represents lines returned by a protocol server.  Indentation and
  white space in the examples are provided only to illustrate element
  relationships and are not a required feature of this protocol.

2. Migrating to Newer Versions of This Extension

  Servers that implement this extension SHOULD provide a way for
  clients to progressively update their implementations when a new
  version of the extension is deployed.
  Servers SHOULD (for a temporary migration period) provide support for
  older versions of the extension in parallel to the newest version and
  allow clients to select their preferred version via the
  <svcExtension> element of the <login> command.
  If a client requests multiple versions of the extension at login,
  then, when preparing responses to commands that do not include
  extension elements, the server SHOULD only include extension elements
  in the namespace of the newest version of the extension requested by
  the client.
  When preparing responses to commands that do include extension
  elements, the server SHOULD only include extension elements for the
  extension versions present in the command.

3. Extension Elements

3.1. Client Commands

  The <fee:command> element is used in the EPP <check> command to
  determine the fee that is applicable to the given command.
  The "name" attribute of the <fee:command> is used to define which
  transform fees the client is requesting information about.  The
  possible values for the "name" attribute are:
  *  "create", indicating a <create> command as defined in [RFC5730].
  *  "delete", indicating a <delete> command as defined in [RFC5730].
  *  "renew", indicating a <renew> command as defined in [RFC5730].
  *  "update", indicating a <update> command as defined in [RFC5730].
  *  "transfer", indicating a <transfer> command as defined in
     [RFC5730].
  *  If the server supports registry grace period mapping [RFC3915],
     then the server MUST also support the "restore" value as defined
     in [RFC3915].
  *  "custom", indicating a custom command that MUST set the
     "customName" attribute with a custom command name.  The possible
     set of custom command name values is dictated by the server
     policy.
  The <fee:command> element MAY have an OPTIONAL "phase" attribute
  specifying a launch phase as described in [RFC8334].  It may also
  contain an OPTIONAL "subphase" attribute identifying the custom or
  subphase as described in [RFC8334].

3.2. Currency Codes

  The <fee:currency> element is used to indicate the currency in which
  fees are charged.  The value of this element MUST be a three-
  character currency code from [ISO4217_2015].
  Note that [ISO4217_2015] provides the special "XXX" code, which MAY
  be used if the server uses a non-currency-based system for assessing
  fees, such as a system of credits.
  The use of <fee:currency> elements in client commands is OPTIONAL: if
  a <fee:currency> element is not present in a command, the server MUST
  determine the currency based on the server default currency or on the
  client's account settings, which are agreed to by the client and
  server via an out-of-band channel.  However, the <fee:currency>
  element MUST be present in the responses.
  Servers SHOULD NOT perform a currency conversion if a client uses an
  incorrect currency code.  Servers SHOULD return a 2004 "Parameter
  value range error" instead.

3.3. Validity Periods

  When querying for fee information using the <check> command, the
  <fee:period> element is used to indicate the validity period, which
  is to be added to extend the registration period of objects by the
  <create>, <renew>, and <transfer> commands.  Validity periods are
  measured in years or months, with the appropriate units specified
  using the "unit" attribute.  Valid values for the "unit" attribute
  are "y" for years and "m" for months.  This element is derived from
  the <domain:period> element described in [RFC5731].
  The <fee:period> element is OPTIONAL in <check> commands; if omitted,
  the server MUST determine the fee(s) using the server default period.
  The <fee:period> element MUST be present in <check> responses.

3.4. Fees and Credits

  Servers that implement this extension will include elements in
  responses that provide information about the fees and/or credits
  associated with a given billable transaction.  A fee will result in
  subtracting from the Account Balance (described in Section 3.5), and
  a credit will result in adding to the Account Balance (described in
  Section 3.5).
  The <fee:fee> and <fee:credit> elements are used to provide this
  information.  The presence of a <fee:fee> element in a response
  indicates a debit against the client's account balance; a
  <fee:credit> element indicates a credit.  A <fee:fee> element MUST
  have a zero or greater (non-negative) value.  A <fee:credit> element
  MUST have a negative value.
  A server MAY respond with multiple <fee:fee> and <fee:credit>
  elements in the same response.  In such cases, the net fee or credit
  applicable to the transaction is the arithmetic sum of the values of
  each of the <fee:fee> and/or <fee:credit> elements.  This amount
  applies to the total additional validity period for the object (where
  applicable).
  The following attributes are defined for the <fee:fee> element.
  These are described in detail below:
  description:  an OPTIONAL attribute that provides a human-readable
     description of the fee.  Servers should provide documentation on
     the possible values of this attribute and their meanings.  An
     OPTIONAL "lang" attribute MAY be present, per the language
     structure in [RFC5646], to identify the language of the returned
     text and has a default value of "en" (English).  If the
     "description" attribute is not present, the "lang" attribute can
     be ignored.
  refundable:  an OPTIONAL boolean attribute indicating whether the fee
     is refundable if the object is deleted.
  grace-period:  an OPTIONAL attribute that provides the time period
     during which the fee is refundable.
  applied:  an OPTIONAL attribute indicating when the fee will be
     deducted from the client's account.
  The <fee:credit> element can take a "description" attribute as
  described above.  An OPTIONAL "lang" attribute MAY be present to
  identify the language of the returned text and has a default value of
  "en" (English).

3.4.1. Refunds

  <fee:fee> elements MAY have an OPTIONAL "refundable" attribute that
  takes a boolean value.  Fees may be refunded under certain
  circumstances, such as when a domain application is rejected (as
  described in [RFC8334]) or when an object is deleted during the
  relevant grace period (see Section 3.4.2).
  If the "refundable" attribute is omitted, then clients SHOULD NOT
  make any assumptions about the refundability of the fee.

3.4.2. Grace Periods

  [RFC3915] describes a system of "grace periods", which are time
  periods following a billable transaction during which, if an object
  is deleted, the client receives a refund.
  The "grace-period" attribute MAY be used to indicate the relevant
  grace period for a fee.  If a server implements the registry grace
  period extension [RFC3915], it MUST specify the grace period for all
  relevant transactions.
  If the "grace-period" attribute is omitted, then clients SHOULD NOT
  make any assumptions about the grace period of the fee.

3.4.3. Correlation between Refundability and Grace Periods

  If a <fee:fee> element has a "grace-period" attribute, then it MUST
  also be refundable, and the "refundable" attribute MUST be true.  If
  the "refundable" attribute of a <fee:fee> element is false, then it
  MUST NOT have a "grace-period" attribute.

3.4.4. Applicability

  Fees may be applied immediately upon receipt of a command from a
  client or may only be applied once an out-of-band process (such as
  the processing of applications at the end of a launch phase) has
  taken place.
  The "applied" attribute of the <fee:fee> element allows servers to
  indicate whether a fee will be applied immediately or whether it will
  be applied at some point in the future.  This attribute takes two
  possible values: "immediate" or "delayed".

3.5. Account Balance

  The <fee:balance> element is an OPTIONAL element that MAY be included
  in server responses to transform commands.  If present, it can be
  used by the client to determine the remaining credit at the server.
  Whether or not the <fee:balance> is included in responses is a matter
  of server policy.  However, if a server chooses to offer support for
  this element, it MUST be included in responses to all "transform" or
  billable commands (e.g., <create>, <renew>, <update>, <delete>,
  <transfer op="request">).
  The value of the <fee:balance> MAY be negative.  A negative balance
  indicates that the server has extended a line of credit to the client
  (see Section 3.6).
  If a server includes a <fee:balance> element in response to transform
  commands, the value of the element MUST reflect the client's account
  balance after any fees or credits associated with that command have
  been applied.  If the "applied" attribute of the <fee:fee> element is
  "delayed", then the <fee:balance> MUST reflect the client's account
  balance without any fees or credits associated with that command.

3.6. Credit Limit

  As described above, if a server returns a response containing a
  <fee:balance> with a negative value, then the server has extended a
  line of credit to the client.  A server MAY also include in responses
  a <fee:creditLimit> element that indicates the maximum credit
  available to a client.  A server MAY reject certain transactions if
  the absolute value of the <fee:balance> is equal to or exceeds the
  value of the <fee:creditLimit> element.
  Whether or not the <fee:creditLimit> is included in responses is a
  matter of server policy.  However, if a server chooses to offer
  support for this element, it MUST be included in responses to all
  "transform" commands (e.g., <create>, <renew>, <update>, <delete>,
  <transfer op="request">).

3.7. Classification of Objects

  Objects may be assigned to a particular class, category, or tier,
  each of which has a particular fee or set of fees associated with it.
  The <fee:class> element, which MAY appear in <check> and transform
  responses, is used to indicate the classification of an object.
  If a server makes use of this element, it should provide clients with
  a list of all the values that the element may take via an out-of-band
  channel.  Servers MUST NOT use values that do not appear on this
  list.
  Servers that make use of this element MUST use a <fee:class> element
  with the value "standard" for all objects that are subject to the
  standard or default fee.

3.8. "Phase" and "Subphase" Attributes

  The <fee:command> element has two attributes, "phase" and "subphase",
  that provide additional information related to a specific launch
  phase, as described in [RFC8334].  These attributes are used as
  filters that should refine the server processing.
  If the client <fee:command> contains a server-supported combination
  of phase/subphase, the server MUST return the fee data (including the
  phase/subphase attribute(s)) for the specific combination.
  If the client <fee:command> contains no "phase"/"subphase" attributes
  and the server has only one active phase/subphase combination, the
  server MUST return the data (including the "phase"/"subphase"
  attribute(s)) of the currently active phase/subphase.
  If the client <fee:command> contains no phase/subphase attributes and
  the server has more than one active phase/subphase combination, the
  server MUST respond with a 2003 "Required parameter missing" error.
  If the client <fee:command> contains no phase/subphase attributes and
  the server is currently in a "quiet period" (e.g., not accepting
  registrations or applications), the server MUST return data
  consistent with the default general availability phase (e.g., "open"
  or "claims"), including the appropriate phase/subphase attribute(s).
  If the client <fee:command> contains a phase attribute with no
  subphase and the server has only one active subphase (or no subphase)
  of this phase, the server MUST return the data (including the phase/
  subphase attribute(s)) of the provided phase and currently active
  subphase.
  If the client <fee:command> contains a phase attribute with no
  subphase and the server has more than one active subphase combination
  of this phase, the server MUST respond with a 2003 "Required
  parameter missing" error.
  If the client <fee:command> contains a subphase with no phase
  attribute, the server MUST respond with a 2003 "Required parameter
  missing" error.
  If the client <fee:command> contains a phase attribute not defined in
  [RFC8334] or not supported by the server, the server MUST respond
  with a 2004 "Parameter value range error".
  If the client <fee:command> contains a subphase attribute (or phase/
  subphase combination) not supported by the server, the server MUST
  respond with a 2004 "Parameter value range error".

3.9. Reason

  The <fee:reason> element is used to provide server-specific text in
  an effort to better explain why a <check> command did not complete as
  the client expected.  An OPTIONAL "lang" attribute MAY be present to
  identify the language, per the language structure in [RFC5646], of
  the returned text and has a default value of "en" (English).
  The <fee:reason> element can be used within the server response
  <fee:command> element or within the <fee:cd> element.  See
  Section 5.1.1 for details on the <fee:cd> "check data" element.
  If the server cannot calculate the relevant fees because the object,
  command, currency, period, class, or some combination is invalid per
  server policy, the server has two ways of handling the error
  processing of <fee:command> element(s):
  1.  Fast-fail: The server, upon error identification, MAY stop
      processing <fee:command> elements and return a <fee:cd> to the
      client containing the <fee:objID> and a <fee:reason> element
      detailing the reason for failure.
         S: <fee:cd avail="0">
         S:   <fee:objID>example.xyz</fee:objID>
         S:   <fee:reason>Only 1 year registration periods are
         S:   valid.</fee:reason>
         S: </fee:cd>
  2.  Partial-fail: The server, upon error identification, MAY continue
      processing <fee:command> elements and return a <fee:cd> to the
      client containing the successfully processed <fee:command>
      elements and failed <fee:command> elements.  All returned failed
      <fee:command> elements MUST have a <fee:reason> element detailing
      the reason for failure, and the server MAY additionally include a
      <fee:reason> element at the <fee:cd> level.
         S: <fee:cd avail="0">
         S:   <fee:objID>example.xyz</fee:objID>
         S:   <fee:command name="create">
         S:     <fee:period unit="y">2</fee:period>
         S:     <fee:reason>Only 1 year registration periods are
         S:     valid.</fee:reason>
         S:   </fee:command>
         S: </fee:cd>
  In either failure scenario, the server MUST set the <fee:cd> "avail"
  attribute to false (0), and the server MUST process all objects in
  the client request.

4. Server Handling of Fee Information

  Depending on the server policy, a client MAY be required to include
  the extension elements described in this document for certain
  transform commands.  Servers must provide clear documentation to
  clients about the circumstances in which this extension must be used.
  The server MUST return avail="0" in its response to a <check> command
  for any object in the <check> command that does not include the
  <fee:check> extension where the server would fail a domain <create>
  command when no <fee> extension is provided for that same object.
  If a server receives a <check> command from a client that results in
  no possible fee combination, the server MUST set the "avail"
  attribute of the <fee:cd> element to false (0) and provide a
  <fee:reason>.
  If a server receives a <check> command from a client that results in
  an ambiguous result (i.e., multiple possible fee combinations), the
  server MUST reject the command with a 2003 "Required parameter
  missing" error.
  If a server receives a command from a client that does not include
  the fee extension data elements required by the server for that
  command, then the server MUST respond with a 2003 "Required parameter
  missing" error.
  If the total fee provided by the client is less than the server's own
  calculation of the fee or the server determines the currency is
  inappropriate for that command, then the server MUST reject the
  command with a 2004 "Parameter value range error".

5. EPP Command Mapping

  A detailed description of the EPP syntax and semantics can be found
  in [RFC5730].

5.1. EPP Query Commands

  This extension does not add any elements to the EPP <poll> or <info>
  commands or responses.

5.1.1. EPP <check> Command

  This extension defines a new command called the Fee Check Command
  that defines additional elements for the EPP <check> command to
  provide fee information.
  The command MAY contain an <extension> element, which MAY contain a
  <fee:check> element.  The <fee:check> element MAY contain one
  <fee:currency> element and MUST contain one or more <fee:command>
  elements.
  The <fee:command> element(s) MUST contain a "name" attribute (see
  Section 3.1), an OPTIONAL "phase" attribute, and an OPTIONAL
  "subphase" attribute (see Section 3.8).  The <fee:command> element(s)
  MAY have the following child elements:
  *  An OPTIONAL <fee:period> element (as described in Section 3.3).
  Example <check> command:
  C: <?xml version="1.0" encoding="utf-8" standalone="no"?>
  C: <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
  C:   <command>
  C:     <check>
  C:       <domain:check
  C:         xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
  C:         <domain:name>example.com</domain:name>
  C:         <domain:name>example.net</domain:name>
  C:         <domain:name>example.xyz</domain:name>
  C:       </domain:check>
  C:     </check>
  C:     <extension>
  C:       <fee:check xmlns:fee="urn:ietf:params:xml:ns:epp:fee-1.0">
  C:         <fee:currency>USD</fee:currency>
  C:         <fee:command name="create">
  C:           <fee:period unit="y">2</fee:period>
  C:         </fee:command>
  C:         <fee:command name="renew"/>
  C:         <fee:command name="transfer"/>
  C:         <fee:command name="restore"/>
  C:       </fee:check>
  C:     </extension>
  C:     <clTRID>ABC-12345</clTRID>
  C:   </command>
  C: </epp>
  When the server receives a <check> command that includes the
  extension elements described above, its response MUST contain an
  <extension> element, which MUST contain a child <fee:chkData>
  element.  The <fee:chkData> element MUST contain a <fee:currency>
  element and a <fee:cd> element for each object referenced in the
  client <check> command.
  Each <fee:cd> (check data) element MUST contain the following child
  elements:
  *  A <fee:objID> element, which MUST match an element referenced in
     the client <check> command.
  *  An OPTIONAL <fee:class> element (as described in Section 3.7).
  *  A <fee:command> element matching each <fee:command> (unless the
     "avail" attribute of the <fee:cd> is false) that appeared in the
     corresponding <fee:check> of the client command.  This element MAY
     have the OPTIONAL "standard" attribute, with a default value of
     "0" (or "false"), which indicates whether the fee is the standard
     or default fee (see Section 3.7).  This element MAY have the
     OPTIONAL "phase" and "subphase" attributes, which will match the
     same attributes in the corresponding <fee:command> element of the
     client command if sent by the client.
  The <fee:cd> element also has an OPTIONAL "avail" attribute, which is
  a boolean.  If the value of this attribute evaluates to false, this
  indicates that the server cannot calculate the relevant fees because
  the object, command, currency, period, class, or some combination is
  invalid per server policy.  If "avail" is false, then the <fee:cd> or
  the <fee:command> element MUST contain a <fee:reason> element (as
  described in Section 3.9), and the server MAY eliminate some or all
  of the <fee:command> element(s).
  The <fee:command> element(s) MAY have the following child elements:
  *  An OPTIONAL <fee:period> element (as described in Section 3.3),
     which contains the same unit, if present, that appeared in the
     <fee:period> element of the command.  If the value of the parent
     <fee:command> element is "restore", this element MUST NOT be
     included; otherwise, it MUST be included.  If no <fee:period>
     appeared in the client command (and the command is not "restore"),
     then the server MUST return its default period value.
  *  Zero or more <fee:fee> elements (as described in Section 3.4).
  *  Zero or more <fee:credit> elements (as described in Section 3.4).
  *  An OPTIONAL <fee:reason> element (as described in Section 3.9).
  If the "avail" attribute of the <fee:cd> element is true (1) and if
  no <fee:fee> elements are present in a <fee:command> element, this
  indicates that no fee will be assessed by the server for this
  command.
  If the "avail" attribute of the <fee:cd> element is true (1), then
  the <fee:command> element MUST NOT contain a <fee:reason> element.
  Example <check> response:
  S: <?xml version="1.0" encoding="utf-8" standalone="no"?>
  S: <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
  S:   <response>
  S:     <result code="1000">
  S:       <msg>Command completed successfully</msg>
  S:     </result>
  S:     <resData>
  S:       <domain:chkData
  S:         xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
  S:         <domain:cd>
  S:           <domain:name avail="1">example.com</domain:name>
  S:         </domain:cd>
  S:         <domain:cd>
  S:           <domain:name avail="1">example.net</domain:name>
  S:         </domain:cd>
  S:         <domain:cd>
  S:           <domain:name avail="1">example.xyz</domain:name>
  S:         </domain:cd>
  S:       </domain:chkData>
  S:     </resData>
  S:     <extension>
  S:       <fee:chkData
  S:           xmlns:fee="urn:ietf:params:xml:ns:epp:fee-1.0">
  S:         <fee:currency>USD</fee:currency>
  S:         <fee:cd avail="1">
  S:           <fee:objID>example.com</fee:objID>
  S:           <fee:class>Premium</fee:class>
  S:           <fee:command name="create">
  S:             <fee:period unit="y">2</fee:period>
  S:             <fee:fee
  S:               description="Registration Fee"
  S:               refundable="1"
  S:               grace-period="P5D">10.00</fee:fee>
  S:           </fee:command>
  S:           <fee:command name="renew">
  S:             <fee:period unit="y">1</fee:period>
  S:             <fee:fee
  S:               description="Renewal Fee"
  S:               refundable="1"
  S:               grace-period="P5D">10.00</fee:fee>
  S:           </fee:command>
  S:           <fee:command name="transfer">
  S:             <fee:period unit="y">1</fee:period>
  S:             <fee:fee
  S:               description="Transfer Fee"
  S:               refundable="1"
  S:               grace-period="P5D">10.00</fee:fee>
  S:           </fee:command>
  S:           <fee:command name="restore">
  S:             <fee:fee
  S:               description="Redemption Fee">15.00</fee:fee>
  S:           </fee:command>
  S:         </fee:cd>
  S:         <fee:cd avail="1">
  S:           <fee:objID>example.net</fee:objID>
  S:           <fee:class>standard</fee:class>
  S:           <fee:command name="create" standard="1">
  S:             <fee:period unit="y">2</fee:period>
  S:             <fee:fee
  S:               description="Registration Fee"
  S:               refundable="1"
  S:               grace-period="P5D">5.00</fee:fee>
  S:           </fee:command>
  S:           <fee:command name="renew" standard="1">
  S:             <fee:period unit="y">1</fee:period>
  S:             <fee:fee
  S:               description="Renewal Fee"
  S:               refundable="1"
  S:               grace-period="P5D">5.00</fee:fee>
  S:           </fee:command>
  S:           <fee:command name="transfer" standard="1">
  S:             <fee:period unit="y">1</fee:period>
  S:             <fee:fee
  S:               description="Transfer Fee"
  S:               refundable="1"
  S:               grace-period="P5D">5.00</fee:fee>
  S:           </fee:command>
  S:           <fee:command name="restore" standard="1">
  S:             <fee:fee
  S:               description="Redemption Fee">5.00</fee:fee>
  S:           </fee:command>
  S:         </fee:cd>
  S:         <fee:cd avail="0">
  S:           <fee:objID>example.xyz</fee:objID>
  S:           <fee:command name="create">
  S:             <fee:period unit="y">2</fee:period>
  S:             <fee:reason>Only 1 year registration periods are
  S:               valid.</fee:reason>
  S:           </fee:command>
  S:         </fee:cd>
  S:       </fee:chkData>
  S:     </extension>
  S:     <trID>
  S:       <clTRID>ABC-12345</clTRID>
  S:       <svTRID>54322-XYZ</svTRID>
  S:     </trID>
  S:   </response>
  S: </epp>

5.1.2. EPP Transfer Query Command

  This extension does not add any elements to the EPP <transfer> query
  command, but it does include elements in the response when the
  extension is included in the <login> command service extensions.
  When the <transfer> query command has been processed successfully, if
  the client has included the extension in the <login> command service
  <svcExtension> element, and if the client is authorized by the server
  to view information about the transfer, then the server MAY include
  in the <extension> section of the EPP response a <fee:trnData>
  element, which contains the following child elements:
  *  A <fee:currency> element (as described in Section 3.2).
  *  A <fee:period> element (as described in Section 3.3).
  *  Zero or more <fee:fee> elements (as described in Section 3.4)
     containing the fees that will be charged to the gaining client.
  *  Zero or more <fee:credit> elements (as described in Section 3.4)
     containing the credits that will be refunded to the losing client.
  Servers SHOULD omit <fee:credit> when returning a response to the
  gaining client and omit <fee:fee> elements when returning a response
  to the losing client.
  If no <fee:trnData> element is included in the response, then no fee
  will be assessed by the server for the transfer.
  Example <transfer> query response:
  S: <?xml version="1.0" encoding="utf-8" standalone="no"?>
  S: <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
  S:   <response>
  S:     <result code="1001">
  S:       <msg>Command completed successfully; action pending</msg>
  S:     </result>
  S:     <resData>
  S:       <domain:trnData
  S:         xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
  S:         <domain:name>example.com</domain:name>
  S:         <domain:trStatus>pending</domain:trStatus>
  S:         <domain:reID>ClientX</domain:reID>
  S:         <domain:reDate>2019-06-08T22:00:00.0Z</domain:reDate>
  S:         <domain:acID>ClientY</domain:acID>
  S:         <domain:acDate>2019-06-13T22:00:00.0Z</domain:acDate>
  S:         <domain:exDate>2021-09-08T22:00:00.0Z</domain:exDate>
  S:       </domain:trnData>
  S:     </resData>
  S:     <extension>
  S:       <fee:trnData xmlns:fee="urn:ietf:params:xml:ns:epp:fee-1.0">
  S:         <fee:currency>USD</fee:currency>
  S:         <fee:period unit="y">1</fee:period>
  S:         <fee:fee>5.00</fee:fee>
  S:       </fee:trnData>
  S:     </extension>
  S:     <trID>
  S:       <clTRID>ABC-12345</clTRID>
  S:       <svTRID>54322-XYZ</svTRID>
  S:     </trID>
  S:   </response>
  S: </epp>

5.2. EPP Transform Commands

5.2.1. EPP <create> Command

  This extension adds elements to both the EPP <create> command and
  response when the extension is included in the <login> command
  service extensions.
  When submitting a <create> command to the server, the client MAY
  include in the <extension> element a <fee:create> element, which
  includes the following child elements:
  *  An OPTIONAL <fee:currency> element (as described in Section 3.2).
  *  One or more <fee:fee> elements (as described in Section 3.4).
  When the <create> command has been processed successfully, the client
  included the extension in the <login> command service extensions, and
  a fee was assessed by the server for the transaction, the server MUST
  include in the <extension> section of the EPP response a
  <fee:creData> element, which contains the following child elements:
  *  A <fee:currency> element (as described in Section 3.2).
  *  Zero or more <fee:fee> elements (as described in Section 3.4).
  *  Zero or more <fee:credit> elements (as described in Section 3.4).
  *  An OPTIONAL <fee:balance> element (as described in Section 3.5).
  *  An OPTIONAL <fee:creditLimit> element (as described in
     Section 3.6).
  Example <create> command:
  C: <?xml version="1.0" encoding="utf-8" standalone="no"?>
  C: <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
  C:   <command>
  C:     <create>
  C:       <domain:create
  C:         xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
  C:         <domain:name>example.com</domain:name>
  C:         <domain:period unit="y">2</domain:period>
  C:         <domain:ns>
  C:           <domain:hostObj>ns1.example.net</domain:hostObj>
  C:           <domain:hostObj>ns2.example.net</domain:hostObj>
  C:         </domain:ns>
  C:         <domain:registrant>jd1234</domain:registrant>
  C:         <domain:contact type="admin">sh8013</domain:contact>
  C:         <domain:contact type="tech">sh8013</domain:contact>
  C:         <domain:authInfo>
  C:           <domain:pw>2fooBAR</domain:pw>
  C:         </domain:authInfo>
  C:       </domain:create>
  C:     </create>
  C:     <extension>
  C:       <fee:create xmlns:fee="urn:ietf:params:xml:ns:epp:fee-1.0">
  C:         <fee:currency>USD</fee:currency>
  C:         <fee:fee>5.00</fee:fee>
  C:       </fee:create>
  C:     </extension>
  C:     <clTRID>ABC-12345</clTRID>
  C:   </command>
  C: </epp>
  Example <create> response:
  S: <?xml version="1.0" encoding="utf-8" standalone="no"?>
  S: <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
  S:   <response>
  S:     <result code="1000">
  S:       <msg>Command completed successfully</msg>
  S:     </result>
  S:     <resData>
  S:       <domain:creData
  S:         xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
  S:         <domain:name>example.com</domain:name>
  S:         <domain:crDate>2019-04-03T22:00:00.0Z</domain:crDate>
  S:         <domain:exDate>2021-04-03T22:00:00.0Z</domain:exDate>
  S:       </domain:creData>
  S:     </resData>
  S:     <extension>
  S:       <fee:creData xmlns:fee="urn:ietf:params:xml:ns:epp:fee-1.0">
  S:         <fee:currency>USD</fee:currency>
  S:         <fee:fee
  S:           description="Registration Fee"
  S:           lang="en"
  S:           refundable="1"
  S:           grace-period="P5D">5.00</fee:fee>
  S:         <fee:balance>-5.00</fee:balance>
  S:         <fee:creditLimit>1000.00</fee:creditLimit>
  S:       </fee:creData>
  S:     </extension>
  S:     <trID>
  S:       <clTRID>ABC-12345</clTRID>
  S:       <svTRID>54321-XYZ</svTRID>
  S:     </trID>
  S:   </response>
  S: </epp>

5.2.2. EPP <delete> Command

  This extension does not add any elements to the EPP <delete> command,
  but it does include elements in the response when the extension is
  included in the <login> command service extensions.
  When the <delete> command has been processed successfully and the
  client included the extension in the <login> command service
  extensions, the server MAY include in the <extension> section of the
  EPP response a <fee:delData> element, which contains the following
  child elements:
  *  A <fee:currency> element (as described in Section 3.2).
  *  Zero or more <fee:fee> elements (as described in Section 3.4).
  *  Zero or more <fee:credit> elements (as described in Section 3.4).
  *  An OPTIONAL <fee:balance> element (as described in Section 3.5).
  *  An OPTIONAL <fee:creditLimit> element (as described in
     Section 3.6).
  Example <delete> response:
  S: <?xml version="1.0" encoding="utf-8" standalone="no"?>
  S: <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
  S:   <response>
  S:     <result code="1000">
  S:       <msg>Command completed successfully</msg>
  S:     </result>
  S:     <extension>
  S:       <fee:delData
  S:         xmlns:fee="urn:ietf:params:xml:ns:epp:fee-1.0">
  S:         <fee:currency>USD</fee:currency>
  S:         <fee:credit
  S:           description="AGP Credit"
  S:           lang="en">-5.00</fee:credit>
  S:         <fee:balance>1005.00</fee:balance>
  S:       </fee:delData>
  S:     </extension>
  S:     <trID>
  S:       <clTRID>ABC-12345</clTRID>
  S:       <svTRID>54321-XYZ</svTRID>
  S:     </trID>
  S:   </response>
  S: </epp>

5.2.3. EPP <renew> Command

  This extension adds elements to both the EPP <renew> command and
  response when the extension is included in the <login> command
  service extensions.
  When submitting a <renew> command to the server, the client MAY
  include in the <extension> element a <fee:renew> element, which
  includes the following child elements:
  *  An OPTIONAL <fee:currency> element (as described in Section 3.2).
  *  One or more <fee:fee> elements (as described in Section 3.4).
  When the <renew> command has been processed successfully and the
  client included the extension in the <login> command service
  extensions, the server MAY include in the <extension> section of the
  EPP response a <fee:renData> element, which contains the following
  child elements:
  *  A <fee:currency> element (as described in Section 3.2).
  *  Zero or more <fee:fee> elements (as described in Section 3.4).
  *  Zero or more <fee:credit> elements (as described in Section 3.4).
  *  An OPTIONAL <fee:balance> element (as described in Section 3.5).
  *  An OPTIONAL <fee:creditLimit> element (as described in
     Section 3.6).
  Example <renew> command:
  C: <?xml version="1.0" encoding="utf-8" standalone="no"?>
  C: <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
  C:   <command>
  C:     <renew>
  C:       <domain:renew
  C:         xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
  C:         <domain:name>example.com</domain:name>
  C:         <domain:curExpDate>2019-04-03</domain:curExpDate>
  C:         <domain:period unit="y">5</domain:period>
  C:       </domain:renew>
  C:     </renew>
  C:     <extension>
  C:       <fee:renew xmlns:fee="urn:ietf:params:xml:ns:epp:fee-1.0">
  C:         <fee:currency>USD</fee:currency>
  C:         <fee:fee>5.00</fee:fee>
  C:       </fee:renew>
  C:     </extension>
  C:     <clTRID>ABC-12345</clTRID>
  C:   </command>
  C: </epp>
  Example <renew> response:
  S: <?xml version="1.0" encoding="utf-8" standalone="no"?>
  S: <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
  S:   <response>
  S:     <result code="1000">
  S:       <msg>Command completed successfully</msg>
  S:     </result>
  S:     <resData>
  S:       <domain:renData
  S:         xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
  S:         <domain:name>example.com</domain:name>
  S:         <domain:exDate>2024-04-03T22:00:00.0Z</domain:exDate>
  S:       </domain:renData>
  S:     </resData>
  S:     <extension>
  S:       <fee:renData xmlns:fee="urn:ietf:params:xml:ns:epp:fee-1.0">
  S:         <fee:currency>USD</fee:currency>
  S:         <fee:fee
  S:           refundable="1"
  S:           grace-period="P5D">5.00</fee:fee>
  S:         <fee:balance>1000.00</fee:balance>
  S:       </fee:renData>
  S:     </extension>
  S:     <trID>
  S:       <clTRID>ABC-12345</clTRID>
  S:       <svTRID>54322-XYZ</svTRID>
  S:     </trID>
  S:   </response>
  S: </epp>

5.2.4. EPP <transfer> Command

  This extension adds elements to both the EPP <transfer> command and
  response when the value of the "op" attribute of the <transfer>
  command element is "request" and the extension is included in the
  <login> command service extensions.
  When submitting a <transfer> command to the server, the client MAY
  include in the <extension> element a <fee:transfer> element, which
  includes the following child elements:
  *  An OPTIONAL <fee:currency> element (as described in Section 3.2).
  *  One or more <fee:fee> elements (as described in Section 3.4).
  When the <transfer> command has been processed successfully and the
  client included the extension in the <login> command service
  extensions, the server MAY include in the <extension> section of the
  EPP response a <fee:trnData> element, which contains the following
  child elements:
  *  A <fee:currency> element (as described in Section 3.2).
  *  Zero or more <fee:fee> elements (as described in Section 3.4).
  *  Zero or more <fee:credit> elements (as described in Section 3.4).
  *  An OPTIONAL <fee:balance> element (as described in Section 3.5).
  *  An OPTIONAL <fee:creditLimit> element (as described in
     Section 3.6).
  Example <transfer> command:
  C: <?xml version="1.0" encoding="utf-8" standalone="no"?>
  C: <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
  C:   <command>
  C:     <transfer op="request">
  C:       <domain:transfer
  C:         xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
  C:         <domain:name>example.com</domain:name>
  C:         <domain:period unit="y">1</domain:period>
  C:         <domain:authInfo>
  C:           <domain:pw roid="JD1234-REP">2fooBAR</domain:pw>
  C:         </domain:authInfo>
  C:       </domain:transfer>
  C:     </transfer>
  C:     <extension>
  C:      <fee:transfer xmlns:fee="urn:ietf:params:xml:ns:epp:fee-1.0">
  C:        <fee:currency>USD</fee:currency>
  C:        <fee:fee>5.00</fee:fee>
  C:      </fee:transfer>
  C:     </extension>
  C:     <clTRID>ABC-12345</clTRID>
  C:   </command>
  C: </epp>
  Example <transfer> response:
  S: <?xml version="1.0" encoding="utf-8" standalone="no"?>
  S: <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
  S:   <response>
  S:     <result code="1001">
  S:       <msg>Command completed successfully; action pending</msg>
  S:     </result>
  S:     <resData>
  S:       <domain:trnData
  S:         xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
  S:         <domain:name>example.com</domain:name>
  S:         <domain:trStatus>pending</domain:trStatus>
  S:         <domain:reID>ClientX</domain:reID>
  S:         <domain:reDate>2019-06-08T22:00:00.0Z</domain:reDate>
  S:         <domain:acID>ClientY</domain:acID>
  S:         <domain:acDate>2019-06-13T22:00:00.0Z</domain:acDate>
  S:         <domain:exDate>2021-09-08T22:00:00.0Z</domain:exDate>
  S:       </domain:trnData>
  S:     </resData>
  S:     <extension>
  S:       <fee:trnData xmlns:fee="urn:ietf:params:xml:ns:epp:fee-1.0">
  S:         <fee:currency>USD</fee:currency>
  S:         <fee:fee
  S:           refundable="1"
  S:           grace-period="P5D">5.00</fee:fee>
  S:       </fee:trnData>
  S:     </extension>
  S:     <trID>
  S:       <clTRID>ABC-12345</clTRID>
  S:       <svTRID>54322-XYZ</svTRID>
  S:     </trID>
  S:   </response>
  S: </epp>

5.2.5. EPP <update> Command

  This extension adds elements to both the EPP <update> command and
  response when the extension is included in the <login> command
  service extensions.
  When submitting an <update> command to the server, the client MAY
  include in the <extension> element a <fee:update> element, which
  includes the following child elements:
  *  An OPTIONAL <fee:currency> element (as described in Section 3.2).
  *  One or more <fee:fee> elements (as described in Section 3.4).
  When the <update> command has been processed successfully and the
  client included the extension in the <login> command service
  extensions, the server MAY include in the <extension> section of the
  EPP response a <fee:updData> element, which contains the following
  child elements:
  *  A <fee:currency> element (as described in Section 3.2).
  *  Zero or more <fee:fee> elements (as described in Section 3.4).
  *  Zero or more <fee:credit> elements (as described in Section 3.4).
  *  An OPTIONAL <fee:balance> element (as described in Section 3.5).
  *  An OPTIONAL <fee:creditLimit> element (as described in
     Section 3.6).
  Example <update> command:
  C: <?xml version="1.0" encoding="utf-8" standalone="no"?>
  C: <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
  C:   <command>
  C:     <update>
  C:       <domain:update
  C:         xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
  C:         <domain:name>example.com</domain:name>
  C:         <domain:chg>
  C:           <domain:registrant>sh8013</domain:registrant>
  C:         </domain:chg>
  C:       </domain:update>
  C:     </update>
  C:     <extension>
  C:       <fee:update xmlns:fee="urn:ietf:params:xml:ns:epp:fee-1.0">
  C:         <fee:currency>USD</fee:currency>
  C:         <fee:fee>5.00</fee:fee>
  C:       </fee:update>
  C:     </extension>
  C:     <clTRID>ABC-12345</clTRID>
  C:   </command>
  C: </epp>
  Example <update> response:
  S: <?xml version="1.0" encoding="utf-8" standalone="no"?>
  S: <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
  S:   <response>
  S:     <result code="1000">
  S:       <msg>Command completed successfully</msg>
  S:     </result>
  S:     <extension>
  S:       <fee:updData xmlns:fee="urn:ietf:params:xml:ns:epp:fee-1.0">
  S:         <fee:currency>USD</fee:currency>
  S:         <fee:fee>5.00</fee:fee>
  S:       </fee:updData>
  S:     </extension>
  S:     <trID>
  S:       <clTRID>ABC-12345</clTRID>
  S:       <svTRID>54321-XYZ</svTRID>
  S:     </trID>
  S:   </response>
  S: </epp>

6. Formal Syntax

  One schema is presented here -- the EPP Fee Extension schema.
  The formal syntax presented here is a complete schema representation
  of the object mapping suitable for automated validation of EPP XML
  instances.

6.1. Fee Extension Schema

  The formal syntax presented here is a complete schema representation
  [W3C.REC-xmlschema-1-20041028] of the object mapping suitable for
  automated validation of EPP XML instances.  The  and
   tags are not part of the schema; they are used to note
  the beginning and end of the schema for URI registration purposes.
  
  <?xml version="1.0" encoding="utf-8"?>
  <schema xmlns="http://www.w3.org/2001/XMLSchema"
    xmlns:fee="urn:ietf:params:xml:ns:epp:fee-1.0"
    xmlns:eppcom="urn:ietf:params:xml:ns:eppcom-1.0"
    xmlns:domain="urn:ietf:params:xml:ns:domain-1.0"
    targetNamespace="urn:ietf:params:xml:ns:epp:fee-1.0"
    elementFormDefault="qualified">
    <import namespace="urn:ietf:params:xml:ns:eppcom-1.0" />
    <import namespace="urn:ietf:params:xml:ns:domain-1.0" />
    <annotation>
      <documentation>
        Extensible Provisioning Protocol v1.0 Fee Extension
      </documentation>
    </annotation>
    <element name="check" type="fee:checkType" />
    <element name="chkData" type="fee:chkDataType" />
    <element name="create" type="fee:transformCommandType" />
    <element name="creData" type="fee:transformResultType" />
    <element name="renew" type="fee:transformCommandType" />
    <element name="renData" type="fee:transformResultType" />
    <element name="transfer" type="fee:transformCommandType" />
    <element name="trnData" type="fee:transformResultType" />
    <element name="update" type="fee:transformCommandType" />
    <element name="updData" type="fee:transformResultType" />
    <element name="delData" type="fee:transformResultType" />
    <complexType name="checkType">
      <sequence>
        <element name="currency" type="fee:currencyType"
          minOccurs="0" />
        <element name="command" type="fee:commandType"
          minOccurs="1" maxOccurs="unbounded" />
      </sequence>
    </complexType>
    <complexType name="objectIdentifierType">
      <simpleContent>
        <extension base="eppcom:labelType">
          <attribute name="element"
          type="NMTOKEN" default="name" />
        </extension>
      </simpleContent>
    </complexType>
    <complexType name="chkDataType">
      <sequence>
        <element name="currency" type="fee:currencyType" />
        <element name="cd" type="fee:objectCDType"
          maxOccurs="unbounded" />
      </sequence>
    </complexType>
    <complexType name="objectCDType">
      <sequence>
        <element name="objID" type="fee:objectIdentifierType" />
        <element name="class" type="token" minOccurs="0" />
        <element name="command" type="fee:commandDataType"
          minOccurs="0" maxOccurs="unbounded" />
        <element name="reason" type="fee:reasonType" minOccurs="0" />
      </sequence>
      <attribute name="avail" type="boolean" default="1" />
    </complexType>
    <complexType name="transformCommandType">
      <sequence>
        <element name="currency" type="fee:currencyType"
          minOccurs="0" />
        <element name="fee" type="fee:feeType"
          maxOccurs="unbounded" />
        <element name="credit" type="fee:creditType"
          minOccurs="0" maxOccurs="unbounded" />
      </sequence>
    </complexType>
    <complexType name="transformResultType">
      <sequence>
        <element name="currency" type="fee:currencyType"
          minOccurs="0" />
        <element name="period" type="domain:periodType"
          minOccurs="0" />
        <element name="fee" type="fee:feeType"
          minOccurs="0" maxOccurs="unbounded" />
        <element name="credit" type="fee:creditType"
          minOccurs="0" maxOccurs="unbounded" />
        <element name="balance" type="fee:balanceType"
          minOccurs="0" />
        <element name="creditLimit" type="fee:creditLimitType"
          minOccurs="0" />
      </sequence>
    </complexType>
    <simpleType name="currencyType">
      <restriction base="string">
        <pattern value="[A-Z]{3}" />
      </restriction>
    </simpleType>
    <complexType name="commandType">
      <sequence>
        <element name="period" type="domain:periodType"
          minOccurs="0" maxOccurs="1" />
      </sequence>
      <attribute name="name" type="fee:commandEnum" use="required"/>
      <attribute name="customName" type="token"/>
      <attribute name="phase" type="token" />
      <attribute name="subphase" type="token" />
    </complexType>
    <complexType name="commandDataType">
      <complexContent>
        <extension base="fee:commandType">
          <sequence>
            <element name="fee" type="fee:feeType"
              minOccurs="0" maxOccurs="unbounded" />
            <element name="credit" type="fee:creditType"
              minOccurs="0" maxOccurs="unbounded" />
            <element name="reason" type="fee:reasonType"
              minOccurs="0" />
          </sequence>
          <attribute name="standard" type="boolean" default="0" />
        </extension>
      </complexContent>
    </complexType>
    <complexType name="reasonType">
      <simpleContent>
        <extension base="token">
          <attribute name="lang" type="language" default="en"/>
        </extension>
      </simpleContent>
    </complexType>
    <simpleType name="commandEnum">
      <restriction base="token">
        <enumeration value="create"/>
        <enumeration value="delete"/>
        <enumeration value="renew"/>
        <enumeration value="update"/>
        <enumeration value="transfer"/>
        <enumeration value="restore"/>
        <enumeration value="custom"/>
      </restriction>
    </simpleType>
    <simpleType name="nonNegativeDecimal">
      <restriction base="decimal">
        <minInclusive value="0" />
      </restriction>
    </simpleType>
    <simpleType name="negativeDecimal">
      <restriction base="decimal">
        <maxInclusive value="0" />
      </restriction>
    </simpleType>
    <complexType name="feeType">
      <simpleContent>
        <extension base="fee:nonNegativeDecimal">
          <attribute name="description"/>
          <attribute name="lang" type="language" default="en"/>
          <attribute name="refundable" type="boolean" />
          <attribute name="grace-period" type="duration" />
          <attribute name="applied">
            <simpleType>
              <restriction base="token">
                <enumeration value="immediate" />
                <enumeration value="delayed" />
              </restriction>
            </simpleType>
          </attribute>
        </extension>
      </simpleContent>
    </complexType>
    <complexType name="creditType">
      <simpleContent>
        <extension base="fee:negativeDecimal">
          <attribute name="description"/>
          <attribute name="lang" type="language" default="en"/>
        </extension>
      </simpleContent>
    </complexType>
    <simpleType name="balanceType">
      <restriction base="decimal" />
    </simpleType>
    <simpleType name="creditLimitType">
      <restriction base="decimal" />
    </simpleType>
  </schema>
  

7. Security Considerations

  The mapping extensions described in this document do not provide any
  security services beyond those described by the EPP [RFC5730], the
  EPP domain name mapping [RFC5731], and the protocol layers used by
  the EPP.  The security considerations described in these other
  specifications apply to this specification as well.  This extension
  passes financial information using the EPP protocol, so
  confidentiality and integrity protection must be provided by the
  transport mechanism.  All transports compliant with [RFC5730] provide
  the needed level of confidentiality and integrity protections.  The
  server will only provide information, including financial
  information, that is relevant to the authenticated client.

8. IANA Considerations

8.1. XML Namespace

  This document uses URNs to describe XML namespaces and XML schemas
  conforming to a registry mechanism described in [RFC3688].
  Registration request for the fee namespace:
  URI: urn:ietf:params:xml:ns:epp:fee-1.0
  Registrant Contact: IESG
  XML: None.  Namespace URIs do not represent an XML specification.
  Registration request for the fee schema:
  URI: urn:ietf:params:xml:schema:epp:fee-1.0
  Registrant Contact: IESG
  XML: See Section 6 of this document.

8.2. EPP Extension Registry

  The EPP extension described in this document has been registered by
  IANA in the "Extensions for the Extensible Provisioning Protocol
  (EPP)" registry described in [RFC7451].  The details of the
  registration are as follows:
  Name of Extension: Registry Fee Extension for the Extensible
  Provisioning Protocol (EPP)
  Document status: Standards Track
  Reference: RFC 8748
  Registrant Name and Email Address: IESG <[email protected]>
  TLDs: Any
  IPR Disclosure: None
  Status: Active
  Notes: None

9. References

9.1. Normative References

  [ISO4217_2015]
             ISO, "Codes for the representation of currencies",
             ISO 4217:2015, August 2015,
             <https://www.iso.org/standard/64758.html>.
  [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119,
             DOI 10.17487/RFC2119, March 1997,
             <https://www.rfc-editor.org/info/rfc2119>.
  [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
             DOI 10.17487/RFC3688, January 2004,
             <https://www.rfc-editor.org/info/rfc3688>.
  [RFC3915]  Hollenbeck, S., "Domain Registry Grace Period Mapping for
             the Extensible Provisioning Protocol (EPP)", RFC 3915,
             DOI 10.17487/RFC3915, September 2004,
             <https://www.rfc-editor.org/info/rfc3915>.
  [RFC5646]  Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
             Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
             September 2009, <https://www.rfc-editor.org/info/rfc5646>.
  [RFC5730]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
             STD 69, RFC 5730, DOI 10.17487/RFC5730, August 2009,
             <https://www.rfc-editor.org/info/rfc5730>.
  [RFC5731]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)
             Domain Name Mapping", STD 69, RFC 5731,
             DOI 10.17487/RFC5731, August 2009,
             <https://www.rfc-editor.org/info/rfc5731>.
  [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
             2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
             May 2017, <https://www.rfc-editor.org/info/rfc8174>.
  [RFC8334]  Gould, J., Tan, W., and G. Brown, "Launch Phase Mapping
             for the Extensible Provisioning Protocol (EPP)", RFC 8334,
             DOI 10.17487/RFC8334, March 2018,
             <https://www.rfc-editor.org/info/rfc8334>.
  [W3C.REC-xmlschema-1-20041028]
             Thompson, H., Beech, D., Maloney, M., and N. Mendelsohn,
             "XML Schema Part 1: Structures Second Edition", World Wide
             Web Consortium Recommendation REC-xmlschema-1-20041028,
             October 2004,
             <http://www.w3.org/TR/2004/REC-xmlschema-1-20041028>.

9.2. Informative References

  [RFC7451]  Hollenbeck, S., "Extension Registry for the Extensible
             Provisioning Protocol", RFC 7451, DOI 10.17487/RFC7451,
             February 2015, <https://www.rfc-editor.org/info/rfc7451>.

Acknowledgements

  The authors wish to thank the following persons for their feedback
  and suggestions:
  *  James Gould of Verisign Inc.
  *  Luis Munoz of ISC
  *  Michael Young
  *  Ben Levac
  *  Jeff Eckhaus
  *  Seth Goldman of Google
  *  Klaus Malorny and Michael Bauland of Knipp
  *  Jody Kolker, Joe Snitker, and Kevin Allendorf of GoDaddy
  *  Michael Holloway of Com Laude
  *  Santosh Kalsangrah of Impetus Infotech
  *  Alex Mayrhofer of Nic.at
  *  Thomas Corte of Knipp Medien und Kommunikation GmbH

Authors' Addresses

  Roger Carney
  GoDaddy Inc.
  14455 N. Hayden Rd. #219
  Scottsdale, AZ 85260
  United States of America
  Email: [email protected]
  URI:   http://www.godaddy.com


  Gavin Brown
  CentralNic Group plc
  35-39 Moorgate
  London
  EC2R 6AR
  United Kingdom
  Phone: +44 20 33 88 0600
  Email: [email protected]
  URI:   http://www.centralnic.com


  Jothan Frakes
  Email: [email protected]
  URI:   http://jothan.com