Network Working Group                                          A. Newton
Request for Comments: 4993                                VeriSign, Inc.
Category: Standards Track                                    August 2007


                 A Lightweight UDP Transfer Protocol
            for the Internet Registry Information Service

Status of This Memo

  This document specifies an Internet standards track protocol for the
  Internet community, and requests discussion and suggestions for
  improvements.  Please refer to the current edition of the "Internet
  Official Protocol Standards" (STD 1) for the standardization state
  and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

  Copyright (C) The IETF Trust (2007).

Abstract

  This document describes a lightweight UDP transfer protocol for the
  Internet Registry Information Service (IRIS).  This transfer protocol
  uses a single packet for every request and response, and optionally
  employs compression over the contents of the packet.

























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RFC 4993      Lightweight UDP Transfer Protocol for IRIS     August 2007


Table of Contents

  1. Introduction ....................................................3
  2. Document Terminology ............................................3
  3. Packet Format ...................................................4
     3.1. Payload Descriptor .........................................4
          3.1.1. Payload Request Descriptor ..........................4
          3.1.2. Payload Response Descriptor .........................5
          3.1.3. Payload Header ......................................6
          3.1.4. Payload Types .......................................6
          3.1.5. Version Information .................................7
          3.1.6. Size Information ....................................8
          3.1.7. Other Information ...................................8
  4. Interactions ....................................................9
  5. Internationalization Considerations ............................10
  6. IRIS Transport Mapping Definitions .............................10
     6.1. URI Scheme ................................................10
     6.2. Application Protocol Label ................................10
  7. IANA Considerations ............................................10
     7.1. Registrations .............................................10
          7.1.1. URI Scheme Registration ............................10
          7.1.2. Well-known UDP Port Registration ...................11
          7.1.3. S-NAPTR Registration ...............................11
  8. Security Considerations ........................................12
  9. References .....................................................13
     9.1. Normative References ......................................13
     9.2. Informative References ....................................13
  Appendix A. Examples ..............................................14
  Appendix B. Contributors ..........................................18






















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1.  Introduction

  Using Straightforward Name Authority Pointers (S-NAPTR) [4], IRIS has
  the ability to define the use of multiple application transports or
  transfer protocols for different types of registry services, all at
  the discretion of the server operator.  The UDP transfer protocol
  defined in this document is completely independent of the registry
  types for which it can carry data.

  The binding of this UDP transfer protocol to IRIS is called IRIS-LWZ
  (for IRIS Lightweight using Compression).  Its message exchange
  pattern is simple: a client sends a request in one UDP packet, and a
  server responds with an answer in one UDP packet.

  IRIS-LWZ packets are composed of two parts, a binary payload
  descriptor and a request/response transaction payload.  The request/
  response transaction payload may be compressed using the DEFLATE [1]
  algorithm.

2.  Document Terminology

  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
  "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
  document are to be interpreted as described in RFC 2119 [6].

  Octet fields with numeric values are given according to the
  conventions in RFC 1166 [10]: the leftmost bit of the whole field is
  the most significant bit; when a multi-octet quantity is transmitted
  the most significant octet is transmitted first.  Bits signifying
  flags in an octet are numbered according to the conventions of RFC
  1166 [10]: bit 0 is the most significant bit and bit 7 is the least
  significant bit.  When a diagram describes a group of octets, the
  order of transmission for the octets starts from the left.


















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RFC 4993      Lightweight UDP Transfer Protocol for IRIS     August 2007


3.  Packet Format

  The packet format for IRIS-LWZ is as follows:

        +------------+---------+
  field |  payload   | payload |
        | descriptor |         |
        +------------+---------+
  octets 3 or 6..261*    0..n

    * In request packets, the payload descriptor can vary in length
      from 6 to 261 octets (i.e., 6..261).  In response packets, the
      payload descriptor is always 3 octets.

                               IRIS-LWZ Packet

      Each IRIS-LWZ query or response is contained in a single UDP
      packet.  Servers MUST be prepared to accept packets as large as
      4000 octets, and clients MUST NOT send packets larger than 4000
      octets.

3.1.  Payload Descriptor

      The payload descriptor has two different formats, one for a
      request and one for a response.  However, each format shares a
      common 1-octet payload header described in Section 3.1.3.

3.1.1.  Payload Request Descriptor

      The payload descriptor for request packets varies from 6 to 261
      octets in length and has the following format:

            +--------+-------------+----------+-----------+-----------+
      field | header | transaction | maximum  | authority | authority |
            |        |     ID      | response |  length   |           |
            |        |             | length   |           |           |
            +--------+-------------+----------+-----------+-----------+
      octets    1           2           2           1         0..255

                         Request Payload Descriptor

      These fields have the following meanings:

      o  header - as described in Section 3.1.3.

  o  transaction ID - a 16-bit value identifying the transaction.  This
     value will be returned in the payload response descriptor (Section
     3.1.2) and can be used by clients to match requests with



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     responses.  Clients SHOULD NOT use sequential values (see Section
     8).  Clients MUST NOT set all the bits in this value to 1 (i.e.,
     use a value of 0xFFFF).

  o  maximum response length - the total length of the UDP packet
     (i.e., UDP header length + payload descriptor length + XML payload
     length) that should not be exceeded when responding to this
     request.  If the server cannot provide a response that is equal to
     or less than this value, then it MUST respond with size
     information (Section 3.1.6).

  o  authority length - the length of the authority field in this
     payload descriptor.

  o  authority - a string of octets describing the authority against
     which this request is to be executed.  See [3] for the definition
     and description of an authority.  The number of octets in this
     string MUST be no more and no less than the number specified by
     the authority length.

3.1.2.  Payload Response Descriptor

  The payload descriptor for response packets is always 3 octets and
  consists of a payload header (Section 3.1.3) and a transaction ID.

        +--------+-------------+
  field | header | transaction |
        |        |     ID      |
        +--------+-------------+
  octets    1           2

                       Payload Response Descriptor

  The purpose of the transaction ID is to allow clients to match
  requests to responses.  A value of 0xFFFF is reserved for server use.
  The value of the transaction ID is as follows:

  1.  If the transaction ID in the corresponding request could not be
      read due to truncation, servers MUST use a transaction ID with
      all bits set to 1 (i.e., a value of OxFFFF) and send a descriptor
      error (see Section 3.1.7).

  2.  If the transaction ID in the corresponding request is a value of
      0xFFFF, servers MUST use a transaction ID of 0xFFFF and send a
      descriptor error (see Section 3.1.7).

  3.  Otherwise, the transaction ID MUST be the value of the
      transaction ID of the corresponding request.



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3.1.3.  Payload Header

  The bits of the payload header are ordered according to RFC 1166
  [10], where bit 0 is the most significant and bit 7 is the least
  significant.  Each bit in the 1-octet payload header has the
  following meaning:

  o  bits 0 and 1 - version number ('V' field) - If 0 (both bits are
     zero), the protocol is the version defined in this document.
     Otherwise, the rest of the bits in the header and the payload may
     be interpreted as another version.

  o  bit 2 - request/response flag ('RR' flag) - If 0, this packet is a
     request (Section 3.1.1) packet.  If 1, this packet is a response
     (Section 3.1.2) packet.

  o  bits 3 - payload deflated ('PD' flag) - If 1, the payload is
     compressed using the DEFLATE [1] algorithm.

  o  bit 4 - deflate supported ('DS' flag) - If 1, the sender of this
     packet supports compression using the DEFLATE algorithm.  When
     this bit is 0 in a request, the payload of the response MUST NOT
     be compressed with DEFLATE.

  o  bit 5 - reserved - This MUST be 0.

  o  bits 6 and 7 - The value of these bits indicates payload types
     (Section 3.1.4) ('PT' field).

3.1.4.  Payload Types

  A payload type indicates the type of content in the UDP packet
  following the payload descriptor.  Some payload types have no meaning
  in request packets, and some payload types differ in meaning between
  requests and responses.  Some payload types indicate an empty
  payload.

  The payload type values in binary are as follows:

     00 - xml payload ('xml' type).  The payload is either an IRIS-
     based XML request or an IRIS-based XML response.

     01 - version info ('vi' type).  In a request packet, this payload
     type indicates that the server is to respond with version
     information (Section 3.1.5), and that the payload is empty.  In a
     response packet, this payload type indicates that the payload is
     version information (Section 3.1.5).




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     10 - size info ('si' type).  This payload type has no meaning in a
     request packet and is a descriptor error.  In a response packet,
     this payload type indicates that the payload is size information
     (Section 3.1.6).

     11 - other info ('oi' type).  This payload type has no meaning in
     a request packet and is a descriptor error.  In a response packet,
     this payload type indicates that the payload is other information
     (Section 3.1.7).

3.1.5.  Version Information

  A payload type with version information ('vi') MUST be conformant to
  the XML defined in [8] and use the <versions> element as the root
  element.

  In the context of IRIS-LWZ, the protocol identifiers for these
  elements are as follows:

     <transferProtocol> - the value "iris.lwz1" to indicate the
     protocol specified in this document.

     <application> - the XML namespace identifier for IRIS [3].

     <dataModel> - the XML namespace identifier for IRIS registries.

  This document defines no extension identifiers and no authentication
  mechanism identifiers.

  Servers SHOULD send version information in the following cases:

  1.  In response to a version information request (i.e., the PT field
      is set to 'vi').

  2.  The version in a payload descriptor header does not match a
      version the server supports.

  3.  The IRIS-based XML payload does not match a version the server
      supports.

  The protocols identified by the <transferProtocol> element MUST only
  indicate protocols running on the same socket as the sender of the
  corresponding response.  In other words, while a server operator may
  also be running IRIS-XPC [9], this XML instance is only intended to
  describe version negotiation for IRIS-LWZ.






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  The octet size for the 'requestSizeOctets' and 'responseSizeOctets'
  attributes of the <tranferProtocol> element are defined in Section
  3.1.6.

3.1.6.  Size Information

  A payload type with size information ('si') MUST be conformant to the
  XML defined in [8] and use the <size> element as the root element.

  Octet counts provided by this information are defined as the total
  length of the UDP packet (i.e., UDP header length + payload
  descriptor length + XML payload length).

3.1.7.  Other Information

  A payload type with other information ('oi') MUST be conformant to
  the XML defined in [8] and use the <other> element as the root
  element.

  The values for the 'type' attribute of <other> are as follows:

     'descriptor-error' - indicates there was an error decoding the
     descriptor.  Servers SHOULD send a descriptor error in the
     following cases:

     1.  When a request is received with a payload type indicating size
         information (i.e., the PT field is 'si').

     2.  When a request is received with a payload type indicating
         other information (i.e., the PT field is 'oi').

     3.  When a request is sent with a transaction ID of 0xFFFF (which
         is reserved for server use).

     4.  When a request is received with an incomplete or truncated
         payload descriptor.

     5.  When reserved bits in the payload descriptor are set to values
         other than zero.

     'payload-error' - indicates there was an error interpreting the
     payload.  Servers MUST send a payload error if they receive XML
     (i.e., the PT field is set to 'xml') and the XML cannot be parsed.

     'system-error' - indicates that the receiver cannot process the
     request due to a condition not related to this protocol.  Servers
     SHOULD send a system-error when they are capable of responding to
     requests but not capable of processing requests.



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     'authority-error' - indicates that the intended authority
     specified in the corresponding request is not served by the
     receiver.  Servers SHOULD send an authority error when they
     receive a request directed to an authority other than those they
     serve.

     'no-inflation-support-error' - indicates that the receiver does
     not support payloads that have been compressed with DEFLATE [1].
     Servers MUST send this error when they receive a request that has
     been compressed with DEFLATE but they do not support inflation.

4.  Interactions

  The intent of IRIS-LWZ is to utilize UDP for IRIS requests and
  responses when UDP is appropriate.  Not all IRIS requests and
  responses will be able to utilize UDP and may require the use of
  other transfer protocols (i.e., IRIS-XPC [9] and/or Blocks Extensible
  Exchange Protocol (BEEP)).  The following strategy SHOULD be used:

  1.  If a request requires authentication, confidentiality, or other
      security, use another transfer protocol.  IRIS-XPC [9] is
      RECOMMENDED.

  2.  The maximum packet size should be calculated as follows:

      a.  If the path MTU is unknown, the maximum packet size MUST be
          1500 octets.

      b.  If the path MTU is known, the maximum packet size MUST NOT
          exceed the path MTU and MUST NOT exceed 4000 octets.

  3.  If a request is less than or equal to the maximum packet size,
      send it uncompressed.

  4.  If a request can be compressed to a size less than or equal to
      the maximum packet size, send the request using compression.
      Otherwise, use another transfer protocol.  In cases where another
      transfer protocol is needed, IRIS-XPC [9] is RECOMMENDED.

  5.  If a request yields a size error, send the request with another
      transfer protocol.  IRIS-XPC [9] is RECOMMENDED.

  For retransmission of requests considered to be unanswered, a client
  SHOULD retransmit using a timeout value initially set to 1 second.
  This timeout value SHOULD be doubled for every retransmission, and a
  client SHOULD NOT retransmit any request once the timeout value has
  reached 60 seconds.




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  Clients that use timeout values other than the recommendations above
  MUST allocate or have allocated dedicated network resources that will
  ensure fairness to other network packets and avoid network
  congestion.

  Clients MUST NOT have more than one outstanding request (i.e., an
  unanswered request that has not timed out) at a time unless they
  allocate or have been allocated dedicated network bandwidth and
  resources reserved specifically for this purpose.

  Finally, if a client intends multiple requests to the same server in
  a short amount of time, this protocol offers no real advantage over
  IRIS-XPC [9].  In such a case, IRIS-XPC is RECOMMENDED to be used as
  it would be similarly or more efficient and would offer greater
  response sizes and allow better security.

5.  Internationalization Considerations

  XML processors are obliged to recognize both UTF-8 and UTF-16 [2]
  encodings.  Use of the XML defined by [8] MUST NOT use any other
  character encodings other than UTF-8 or UTF-16.

6.  IRIS Transport Mapping Definitions

  This section lists the definitions required by IRIS [3] for transport
  mappings.

6.1.  URI Scheme

  See Section 7.1.1.

6.2.  Application Protocol Label

  See Section 7.1.3.

7.  IANA Considerations

7.1.  Registrations

7.1.1.  URI Scheme Registration

  URL scheme name: iris.lwz

  Status: permanent

  URL scheme syntax: defined in [3].

  Character encoding considerations: as defined in RFC 3986 [5].



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  Intended usage: identifies an IRIS entity made available using XML
  over UDP

  Applications using this scheme: defined in IRIS [3].

  Interoperability considerations: n/a

  Security Considerations: defined in Section 8.

  Relevant Publications: IRIS [3].

  Contact Information: Andrew Newton <[email protected]>

  Author/Change controller: the IESG

7.1.2.  Well-known UDP Port Registration

  Protocol Number: UDP

  UDP Port Number: 715

  Message Formats, Types, Opcodes, and Sequences: defined in Sections 3
  and 3.1.

  Functions: defined in IRIS [3].

  Use of Broadcast/Multicast: none

  Proposed Name: IRIS-LWZ

  Short name: iris.lwz

  Contact Information: Andrew Newton <[email protected]>

7.1.3.  S-NAPTR Registration

  Application Protocol Label (see [4]): iris.lwz

  Intended usage: identifies an IRIS server using XML over UDP

  Interoperability considerations: n/a

  Security Considerations: defined in Section 8.

  Relevant Publications: IRIS [3].

  Contact Information: Andrew Newton <[email protected]>




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  Author/Change controller: the IESG

8.  Security Considerations

  IRIS-LWZ is intended for serving public data; it provides no in-band
  mechanisms for authentication or confidentiality.  Any application
  with these needs must provide out-of-band mechanisms (e.g., IPsec),
  or use the IRIS transfer protocols that provide such capabilities,
  such as IRIS-XPC [9].

  Due to this lack of security, it is possible for an attacker to alter
  IRIS-LWZ messages sent from the client to the server and from the
  server to the client.  Such an attack can result in denying usage of
  an IRIS service or in supplying false information to end users and
  many other scenarios.

  Because IRIS-LWZ is a UDP-based protocol, it is possible for servers
  using IRIS-LWZ to be used in a type of distributed denial-of-service
  attack known as a reflection attack.  This type of attack affects
  other types of UDP-using protocols, such as DNS.  Server operators
  should be prepared to apply the same methods used for mitigating
  reflection attacks with other protocols, such as DNS, when using
  IRIS-LWZ.  All operators should follow the advice given in BCP 38
  [7].

  IRIS-LWZ uses transaction IDs in the payload descriptors to better
  enable a client to match a response to a request.  By randomizing the
  transaction IDs being used (i.e., not using sequential numbers),
  attackers flooding the network with a large amount of spoofed packets
  have a lesser chance of succeeding with the attack.  This measure is
  not guaranteed to thwart any such attack.  Client implementers MUST
  take appropriate measures when ignoring this advice.



















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9.  References

9.1.  Normative References

  [1]   Deutsch, P., "DEFLATE Compressed Data Format Specification
        version 1.3", RFC 1951, May 1996.

  [2]   The Unicode Consortium, "The Unicode Standard, Version 3", ISBN
        0-201-61633-5, 2000, <The Unicode Standard, Version 3>.

  [3]   Newton, A. and M. Sanz, "IRIS: The Internet Registry
        Information Service (IRIS) Core Protocol", RFC 3981, January
        2005.

  [4]   Daigle, L. and A. Newton, "Domain-Based Application Service
        Location Using SRV RRs and the Dynamic Delegation Discovery
        Service (DDDS)", RFC 3958, January 2005.

  [5]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
        Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986,
        January 2005.

  [6]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
        Levels", RFC 2119, BCP 14, March 1997.

  [7]   Ferguson, P. and D. Senie, "Network Ingress Filtering:
        Defeating Denial of Service Attacks which employ IP Source
        Address Spoofing", BCP 38, RFC 2827, May 2000.

  [8]   Newton, A., "A Common Schema for Internet Registry Information
        Service Transfer Protocols", RFC 4991, August 2007.

  [9]   Newton, A., "XML Pipelining with Chunks for the Internet
        Registry Information Service", RFC 4992, August 2007.

9.2.  Informative References

  [10]  Kirkpatrick, S., Stahl, M., and M. Recker, "Internet numbers",
        RFC 1166, July 1990.












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Appendix A.  Examples

  This section gives examples of IRIS-LWZ exchanges.  Lines beginning
  with "C:" denote data sent by the client to the server, and lines
  beginning with "S:" denote data sent by the server to the client.
  Following the "C:" or "S:", the line contains either octet values in
  hexadecimal notation with comments or XML fragments.  No line
  contains both octet values with comments and XML fragments.  Comments
  are contained within parentheses.










































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  The following example demonstrates an IRIS client requesting a lookup
  of 'AUP' in the 'local' entity class of a 'dreg1' registry.  The
  client passes a bag (see [3]) with the search request.  The server
  responds with a 'nameNotFound' response and an explanation.

  C:           (request packet)
  C: 0x08      (header: V=0,RR=request,PD=no,DS=yes,PT=xml)
  C: 0x03 0xA4 (transaction ID=932)
  C: 0x05 0xDA (maximum response size=1498)
  C: 0x09      (authority length=9)
  C:           (authority="localhost")
  C: 0x6c 0x6f 0x63 0x61 0x6c 0x68 0x6f 0x73 0x74
  C:           (IRIS XML request)
  C: <request xmlns="urn:ietf:params:xml:ns:iris1"
  C:    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >
  C:    <searchSet>
  C:      <bag>
  C:        <simpleBag xmlns="http://example.com/">
  C:          <salt>127.0.0.1:3434</salt>
  C:          <md5>4LnQ1KdCahzyvwBqJis5rw==</md5>
  C:        </simpleBag>
  C:      </bag>
  C:      <lookupEntity
  C:        registryType="dreg1"
  C:        entityClass="local"
  C:        entityName="AUP" />
  C:    </searchSet>
  C: </request>

  S:           (response packet)
  S: 0x20      (header: V=0,RR=response,PD=no,DS=no,PT=xml)
  S: 0x03 0xA4 (transaction ID=932)
  S:           (IRIS XML response)
  S: <iris:response xmlns:iris="urn:ietf:params:xml:ns:iris1">
  S: <iris:resultSet><iris:answer></iris:answer>
  S: <iris:nameNotFound><iris:explanation language="en-US">
  S: The name 'AUP' is not found in 'local'.</iris:explanation>
  S: </iris:nameNotFound></iris:resultSet></iris:response>

                                Example 1











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RFC 4993      Lightweight UDP Transfer Protocol for IRIS     August 2007


  The following example demonstrates an IRIS client requesting domain
  availability information for 'milo.example.com'.  The server responds
  that the domain is assigned and active.

  C:           (request packet)
  C: 0x00      (header: V=0,RR=request,PD=no,DS=no,PT=xml)
  C: 0x0B 0xE7 (transaction ID=3047)
  C: 0x0F 0xA0 (maximum response size=4000)
  C: 0x0B      (authority length=11)
  C:           (authority="example.com")
  C: 0x65 0x78 0x61 0x6D 0x70 0x6C 0x65 0x23 0x63 0x6F 0x6D
  C:           (IRIS XML request)
  C: <request xmlns="urn:ietf:params:xml:ns:iris1"
  C:   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  C:   xsi:schemaLocation="urn:ietf:params:xml:ns:iris1 iris.xsd" >
  C:   <searchSet>
  C:     <lookupEntity
  C:       registryType="urn:ietf:params:xml:ns:dchk1"
  C:       entityClass="domain-name"
  C:       entityName="milo.example.com" />
  C:   </searchSet>
  C: </request>

  S:           (response packet)
  S: 0x20      (header: V=0,RR=response,PD=no,DS=no,PT=xml)
  S: 0x0B 0xE7 (transaction ID=3047)
  S:           (IRIS XML response)
  S: <iris:response xmlns:iris="urn:ietf:params:xml:ns:iris1">
  S: <iris:resultSet><iris:answer><domain
  S: authority="example.com" registryType="dchk1"
  S: entityClass="domain-name" entityName="tcs-com-1"
  S: temporaryReference="true"
  S: xmlns="urn:ietf:params:xml:ns:dchk1"><domainName>
  S: milo.example.com</domainName><status><assignedAndActive/>
  S: </status></domain></iris:answer>
  S: </iris:resultSet></iris:response>

                                Example 2













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RFC 4993      Lightweight UDP Transfer Protocol for IRIS     August 2007


  The following example demonstrates an IRIS client requesting domain
  availability information for felix.example.net, hobbes.example.net,
  and daffy.example.net.  The client does not support responses
  compressed with DEFLATE, and the maximum UDP packet it can safely
  receive is 498 octets.  The server responds with size information
  indicating that it would take 1211 octets to provide an answer.

  C:           (request packet)
  C: 0x00      (header: V=0,RR=request,PD=no,DS=no,PT=xml)
  C: 0x7E 0x8A (transaction ID=32394)
  C: 0x01 0xF2 (maximum response size=498)
  C: 0x0B      (authority length=11)
  C:           (authority="example.net")
  C: 0x65 0x78 0x61 0x6D 0x70 0x6C 0x65 0x23 0x6E 0x65 0x74
  C:           (IRIS XML request)
  C: <request xmlns="urn:ietf:params:xml:ns:iris1"
  C:   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  C:   xsi:schemaLocation="urn:ietf:params:xml:ns:iris1 iris1.xsd">
  C:   <searchSet>
  C:     <lookupEntity registryType="dchk1" entityClass="domain-name"
  C:       entityName="felix.example.net" />
  C:   </searchSet>
  C:   <searchSet>
  C:     <lookupEntity registryType="dchk1" entityClass="domain-name"
  C:       entityName="hobbes.example.net" />
  C:   </searchSet>
  C:   <searchSet>
  C:     <lookupEntity registryType="dchk1" entityClass="domain-name"
  C:       entityName="daffy.example.net" />
  C:   </searchSet>
  C: </request>

  S:           (response packet)
  S: 0x22      (header: V=0,RR=response,PD=no,DS=no,PT=si)
  S: 0x7E 0x8A (transaction ID=32394)
  S:           (Size Information XML response)
  S: <responseSize xmlns="urn:ietf:params:xml:ns:iris-transport">
  S:   <octets>1211</octets>
  S: </responseSize>

                                Example 3










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RFC 4993      Lightweight UDP Transfer Protocol for IRIS     August 2007


  The following example illustrates an IRIS client requesting the
  version information from a server, and the server returning the
  version information.

  C:           (request packet)
  C: 0x01      (header: V=0,RR=request,PD=no,DS=no,PT=vi)
  C: 0x2E 0x9C (transaction ID=11932)
  C: 0x01 0xF2 (maximum response size=498)
  C: 0x0B      (authority length=11)
  C:           (authority="example.net")
  C: 0x65 0x78 0x61 0x6D 0x70 0x6C 0x65 0x23 0x6E 0x65 0x74

  S:           (response packet)
  S: 0x21      (header: V=0,RR=response,PD=no,DS=no,PT=vi)
  S: 0x2E 0x9C (transaction ID=11932)
  S:           (Version Information XML response)
  S: <versions xmlns="urn:ietf:params:xml:ns:iris-transport">
  S:   <transferProtocol protocolId="iris.lwz1">
  S:     <application protocolId="urn:ietf:params:xml:ns:iris1">
  S:       <dataModel protocolId="urn:ietf:params:xml:ns:dchk1"/>
  S:       <dataModel protocolId="urn:ietf:params:xml:ns:dreg1"/>
  S:     </application>
  S:   </transferProtocol>
  S: </versions>

                                Example 4

Appendix B.  Contributors

  Substantive contributions to this document have been provided by the
  members of the IETF's CRISP Working Group, especially Milena Caires
  and David Blacka.

Author's Address

  Andrew L. Newton
  VeriSign, Inc.
  21345 Ridgetop Circle
  Sterling, VA  20166
  USA

  Phone: +1 703 948 3382
  EMail: [email protected]
  URI:   http://www.verisignlabs.com/







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RFC 4993      Lightweight UDP Transfer Protocol for IRIS     August 2007


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