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RFC 5457


Independent Submission                                       E. Guy, Ed.
Request for Comments: 5457                                      Truphone
Category: Informational                                    February 2010
ISSN: 2070-1721

     IANA Considerations for IAX: Inter-Asterisk eXchange Version 2

Abstract

   This document establishes the IANA registries for IAX, the Inter-
   Asterisk eXchange protocol, an application-layer control and media
   protocol for creating, modifying, and terminating multimedia sessions
   over Internet Protocol (IP) networks.  IAX was developed by the open
   source community for the Asterisk PBX and is targeted primarily at
   Voice over Internet Protocol (VoIP) call control, but it can be used
   with streaming video or any other type of multimedia.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This is a contribution to the RFC Series, independently of any other
   RFC stream.  The RFC Editor has chosen to publish this document at
   its discretion and makes no statement about its value for
   implementation or deployment.  Documents approved for publication by
   the RFC Editor are not a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc5457.

IESG Note

   The IESG thinks that this work is related to IETF work done in SIP,
   MMUSIC, and AVT WGs, but this does not prevent publishing.

Guy                           Informational                     [Page 1]



RFC 5457                 IANA IAX Considerations           February 2010

Copyright Notice

   Copyright (c) 2010 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
   (http://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.

Table of Contents

   1. Introduction ....................................................2
   2. IANA Considerations .............................................3
      2.1. Meta Command ...............................................3
      2.2. Frame Types ................................................3
      2.3. Control Frame Subclass .....................................4
      2.4. IAX Control Frames .........................................6
      2.5. HTML Command Subclasses ....................................8
      2.6. Information Elements .......................................8
      2.7. Authentication Methods ....................................11
      2.8. Dialplan Status Flags .....................................12
      2.9. Calling Presentation ......................................12
      2.10. Calling Type of Number (CALLINGTON) ......................13
      2.11. IAX Transit Network Identification .......................14
      2.12. IAX Type of Network ......................................15
      2.13. Cause Codes ..............................................16
      2.14. Encryption Methods .......................................18
      2.15. Media Formats ............................................19
   3. Security Considerations ........................................20
   4. Acknowledgments ................................................20
   5. Normative References ...........................................20

1.  Introduction

   IAX (Inter-Asterisk eXchange) is an "all-in-one" protocol for
   handling multimedia in IP networks.  It combines both control and
   media services in the same protocol.  In addition, IAX uses a single
   UDP data stream on a static port greatly simplifying Network Address
   Translation (NAT) gateway traversal, eliminating the need for other
   protocols to work around NAT, and simplifying network and firewall
   management.  IAX employs a compact encoding that decreases bandwidth
   usage and is well suited for Internet telephony service.  In
   addition, its open nature permits new payload type additions needed
   to support additional services.

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RFC 5457                 IANA IAX Considerations           February 2010

   This document specifies and provides the initial values for the
   creation of the IAX-related IANA registries as per [RFC5226].

2.  IANA Considerations

   The IAX protocol, as defined in [RFC5456], defines 15 namespaces that
   have been registered.  These namespaces are described below.

   Each of these namespaces utilizes an 'Expert Review' for extension.
   Documentation of new values is not mandated as RFCs.  The Expert
   Review should be guided by a few common sense considerations.  For
   example, new values should not be specific to a country, region,
   organization, or company; they should be well-defined and widely
   recognized.

2.1.  Meta Command

   Registry Name: IAX Meta Commands

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.

   Description: See Section 8.1.3.2 of [RFC5456].

   Valid Range: 0x01-x7F.

   Display format: hex.

   The following table specifies the initial assignments of Meta Command
   values:

   +------+-----------------+------------------------------------------+
   | TYPE | Name            | Description                              |
   +------+-----------------+------------------------------------------+
   | 0x01 | Trunk Meta      | Indicates that frame is a trunk meta     |
   |      | Frame           | frame.                                   |
   +------+-----------------+------------------------------------------+

2.2.  Frame Types

   Registry Name: IAX Frame Types

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.  In addition, the definition and
   description of subclasses.

   Description: See Section 8.2 of [RFC5456].

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RFC 5457                 IANA IAX Considerations           February 2010

   Valid Range: 0x01-xFF.

   Display format: hex.

   The following table specifies the initial assignments of Frame Type
   Values:

   +------+-------------+--------------------------+-------------------+
   | TYPE | Description | Subclass Description     | Data Description  |
   +------+-------------+--------------------------+-------------------+
   | 0x01 | DTMF        | 0-9, A-D, *, #           | Undefined         |
   |      |             |                          |                   |
   | 0x02 | Voice       | Audio Compression Format | Data              |
   |      |             |                          |                   |
   | 0x03 | Video       | Video Compression Format | Data              |
   |      |             |                          |                   |
   | 0x04 | Control     | See Control Frame        | Varies with       |
   |      |             | Subclass                 | subclass          |
   |      |             |                          |                   |
   | 0x05 | Null        | Undefined                | Undefined         |
   |      |             |                          |                   |
   | 0x06 | IAX Control | See IAX Protocol         | Information       |
   |      |             | Messages                 | Elements          |
   |      |             |                          |                   |
   | 0x07 | Text        | Always 0                 | Raw Text          |
   |      |             |                          |                   |
   | 0x08 | Image       | Image Compression Format | Raw image         |
   |      |             |                          |                   |
   | 0x09 | HTML        | See HTML Frame Types     | Message Specific  |
   |      |             |                          |                   |
   | 0x0A | Comfort     | Level in -dBov of        | None              |
   |      | Noise       | comfort noise            |                   |
   +------+-------------+--------------------------+-------------------+

2.3.  Control Frame Subclass

   Registry Name: IAX Control Frame Subclass

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.

   Description: See Section 8.3 of [RFC5456].

   Valid Range: 0x00-x7F.

   Display format: hex.

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RFC 5457                 IANA IAX Considerations           February 2010

   The following table specifies the initial assignments of Control
   Frame Subclasses:

   +-------------+---------------+-------------------------------------+
   | VALUE       | Name          | Description                         |
   +-------------+---------------+-------------------------------------+
   | 0x01        | Hangup        | The call has been hungup at the     |
   |             |               | remote end                          |
   |             |               |                                     |
   | 0x02        | Reserved      | Reserved for future use             |
   |             |               |                                     |
   | 0x03        | Ringing       | Remote end is ringing (ring-back)   |
   |             |               |                                     |
   | 0x04        | Answer        | Remote end has answered             |
   |             |               |                                     |
   | 0x05        | Busy          | Remote end is busy                  |
   |             |               |                                     |
   | 0x06        | Reserved      | Reserved for future use             |
   |             |               |                                     |
   | 0x07        | Reserved      | Reserved for future use             |
   |             |               |                                     |
   | 0x08        | Congestion    | The call is congested               |
   |             |               |                                     |
   | 0x09        | Flash Hook    | Flash hook                          |
   |             |               |                                     |
   | 0x0a        | Reserved      | Reserved for future use             |
   |             |               |                                     |
   | 0x0b        | Option        | Device-specific options are being   |
   |             |               | transmitted                         |
   |             |               |                                     |
   | 0x0c        | Key Radio     | Key Radio                           |
   |             |               |                                     |
   | 0x0d        | Unkey Radio   | Unkey Radio                         |
   |             |               |                                     |
   | 0x0e        | Call Progress | Call is in progress                 |
   |             |               |                                     |
   | 0x0f        | Call          | Call is proceeding                  |
   |             | Proceeding    |                                     |
   |             |               |                                     |
   | 0x10        | Hold          | Call is placed on hold              |
   |             |               |                                     |
   | 0x11        | Unhold        | Call is taken off hold              |
   +-------------+---------------+-------------------------------------+

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RFC 5457                 IANA IAX Considerations           February 2010

2.4.  IAX Control Frames

   Registry Name: IAX Control Frames

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.

   Description: See Section 8.4 of [RFC5456].

   Valid Range: 0x01-x7F.

   Display format: hex.

   The following table specifies the initial assignments of IAX Control
   Frame values:

      +------+-----------+-----------------------------------------+
      | Hex  | Name      | Description                             |
      +------+-----------+-----------------------------------------+
      | 0x01 | NEW       | Initiate a new call                     |
      |      |           |                                         |
      | 0x02 | PING      | Ping request                            |
      |      |           |                                         |
      | 0x03 | PONG      | Ping or poke reply                      |
      |      |           |                                         |
      | 0x04 | ACK       | Explicit acknowledgment                 |
      |      |           |                                         |
      | 0x05 | HANGUP    | Initiate call tear-down                 |
      |      |           |                                         |
      | 0x06 | REJECT    | Reject a call                           |
      |      |           |                                         |
      | 0x07 | ACCEPT    | Accept a call                           |
      |      |           |                                         |
      | 0x08 | AUTHREQ   | Authentication request                  |
      |      |           |                                         |
      | 0x09 | AUTHREP   | Authentication reply                    |
      |      |           |                                         |
      | 0x0a | INVAL     | Invalid message                         |
      |      |           |                                         |
      | 0x0b | LAGRQ     | Lag request                             |
      |      |           |                                         |
      | 0x0c | LAGRP     | Lag reply                               |
      |      |           |                                         |
      | 0x0d | REGREQ    | Registration request                    |
      |      |           |                                         |
      | 0x0e | REGAUTH   | Registration authentication             |
      |      |           |                                         |
      | 0x0f | REGACK    | Registration acknowledgement            |

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RFC 5457                 IANA IAX Considerations           February 2010

      |      |           |                                         |
      | 0x10 | REGREJ    | Registration reject                     |
      |      |           |                                         |
      | 0x11 | REGREL    | Registration release                    |
      |      |           |                                         |
      | 0x12 | VNAK      | Video/Voice retransmit request          |
      |      |           |                                         |
      | 0x13 | DPREQ     | Dialplan request                        |
      |      |           |                                         |
      | 0x14 | DPREP     | Dialplan reply                          |
      |      |           |                                         |
      | 0x15 | DIAL      | Dial                                    |
      |      |           |                                         |
      | 0x16 | TXREQ     | Transfer request                        |
      |      |           |                                         |
      | 0x17 | TXCNT     | Transfer connect                        |
      |      |           |                                         |
      | 0x18 | TXACC     | Transfer accept                         |
      |      |           |                                         |
      | 0x19 | TXREADY   | Transfer ready                          |
      |      |           |                                         |
      | 0x1a | TXREL     | Transfer release                        |
      |      |           |                                         |
      | 0x1b | TXREJ     | Transfer reject                         |
      |      |           |                                         |
      | 0x1c | QUELCH    | Halt audio/video [media] transmission   |
      |      |           |                                         |
      | 0x1d | UNQUELCH  | Resume audio/video [media] transmission |
      |      |           |                                         |
      | 0x1e | POKE      | Poke request                            |
      |      |           |                                         |
      | 0x1f | Reserved  | Reserved for future use                 |
      |      |           |                                         |
      | 0x20 | MWI       | Message waiting indication              |
      |      |           |                                         |
      | 0x21 | UNSUPPORT | Unsupported message                     |
      |      |           |                                         |
      | 0x22 | TRANSFER  | Remote transfer request                 |
      |      |           |                                         |
      | 0x23 | Reserved  | Reserved for future use                 |
      |      |           |                                         |
      | 0x24 | Reserved  | Reserved for future use                 |
      |      |           |                                         |
      | 0x25 | Reserved  | Reserved for future use                 |
      +------+-----------+-----------------------------------------+

Guy                           Informational                     [Page 7]



RFC 5457                 IANA IAX Considerations           February 2010

2.5.  HTML Command Subclasses

   Registry Name: IAX HTML Command Subclasses

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.

   Description: See Section 8.2 of [RFC5456].

   Valid Range: 0x01-x7F.

   Display format: hex.

   The following table specifies the initial assignments of IAX HTML
   Command Subclasses:

                  +--------+----------------------------+
                  | NUMBER | DESCRIPTION                |
                  +--------+----------------------------+
                  | 0x01   | Sending a URL              |
                  |        |                            |
                  | 0x02   | Data frame                 |
                  |        |                            |
                  | 0x04   | Beginning frame            |
                  |        |                            |
                  | 0x08   | End frame                  |
                  |        |                            |
                  | 0x10   | Load is complete           |
                  |        |                            |
                  | 0x11   | Peer does not support HTML |
                  |        |                            |
                  | 0x12   | Link URL                   |
                  |        |                            |
                  | 0x13   | Unlink URL                 |
                  |        |                            |
                  | 0x14   | Reject Link URL            |
                  +--------+----------------------------+

2.6.  Information Elements

   Registry Name: IAX Information Elements

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.

   Description: See Section 8.6 of [RFC5456].

   Valid Range: 0x01-xFF.

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RFC 5457                 IANA IAX Considerations           February 2010

   Display format: hex.

   The following table specifies the Initial Assignments of Information
   Element Definitions:

   +------+----------------+-------------------------------------------+
   | HEX  | NAME           | DESCRIPTION                               |
   +------+----------------+-------------------------------------------+
   | 0x01 | CALLED NUMBER  | Number/extension being called             |
   |      |                |                                           |
   | 0x02 | CALLING NUMBER | Calling number                            |
   |      |                |                                           |
   | 0x03 | CALLING ANI    | Calling number ANI for billing            |
   |      |                |                                           |
   | 0x04 | CALLING NAME   | Name of caller                            |
   |      |                |                                           |
   | 0x05 | CALLED CONTEXT | Context for number                        |
   |      |                |                                           |
   | 0x06 | USERNAME       | Username (peer or user) for               |
   |      |                | authentication                            |
   |      |                |                                           |
   | 0x07 | PASSWORD       | Password for authentication               |
   |      |                |                                           |
   | 0x08 | CAPABILITY     | Actual CODEC capability                   |
   |      |                |                                           |
   | 0x09 | FORMAT         | Desired CODEC format                      |
   |      |                |                                           |
   | 0x0a | LANGUAGE       | Desired language                          |
   |      |                |                                           |
   | 0x0b | VERSION        | Protocol version                          |
   |      |                |                                           |
   | 0x0c | ADSICPE        | CPE ADSI capability                       |
   |      |                |                                           |
   | 0x0d | DNID           | Originally dialed DNID                    |
   |      |                |                                           |
   | 0x0e | AUTHMETHODS    | Authentication method(s)                  |
   |      |                |                                           |
   | 0x0f | CHALLENGE      | Challenge data for MD5/RSA                |
   |      |                |                                           |
   | 0x10 | MD5 RESULT     | MD5 challenge result                      |
   |      |                |                                           |
   | 0x11 | RSA RESULT     | RSA challenge result                      |
   |      |                |                                           |
   | 0x12 | APPARENT ADDR  | Apparent address of peer                  |
   |      |                |                                           |
   | 0x13 | REFRESH        | When to refresh registration              |
   |      |                |                                           |
   | 0x14 | DPSTATUS       | Dialplan status                           |

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RFC 5457                 IANA IAX Considerations           February 2010

   |      |                |                                           |
   | 0x15 | CALLNO         | Call number of peer                       |
   |      |                |                                           |
   | 0x16 | CAUSE          | Cause                                     |
   |      |                |                                           |
   | 0x17 | IAX UNKNOWN    | Unknown IAX command                       |
   |      |                |                                           |
   | 0x18 | MSGCOUNT       | How many messages waiting                 |
   |      |                |                                           |
   | 0x19 | AUTOANSWER     | Request auto-answering                    |
   |      |                |                                           |
   | 0x1a | MUSICONHOLD    | Request musiconhold with QUELCH           |
   |      |                |                                           |
   | 0x1b | TRANSFERID     | Transfer Request Identifier               |
   |      |                |                                           |
   | 0x1c | RDNIS          | Referring DNIS                            |
   |      |                |                                           |
   | 0x1d | Reserved       | Reserved for future use                   |
   |      |                |                                           |
   | 0x1e | Reserved       | Reserved for future use                   |
   |      |                |                                           |
   | 0x1f | DATETIME       | Date/Time                                 |
   |      |                |                                           |
   | 0x20 | Reserved       | Reserved for future use                   |
   |      |                |                                           |
   | 0x21 | Reserved       | Reserved for future use                   |
   |      |                |                                           |
   | 0x22 | Reserved       | Reserved for future use                   |
   |      |                |                                           |
   | 0x23 | Reserved       | Reserved for future use                   |
   |      |                |                                           |
   | 0x24 | Reserved       | Reserved for future use                   |
   |      |                |                                           |
   | 0x25 | Reserved       | Reserved for future use                   |
   |      |                |                                           |
   | 0x26 | CALLINGPRES    | Calling presentation                      |
   |      |                |                                           |
   | 0x27 | CALLINGTON     | Calling type of number                    |
   |      |                |                                           |
   | 0x28 | CALLINGTNS     | Calling transit network select            |
   |      |                |                                           |
   | 0x29 | SAMPLINGRATE   | Supported sampling rates                  |
   |      |                |                                           |
   | 0x2a | CAUSECODE      | Hangup cause                              |
   |      |                |                                           |
   | 0x2b | ENCRYPTION     | Encryption format                         |
   |      |                |                                           |
   | 0x2c | ENCKEY         | Reserved for future use                   |

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RFC 5457                 IANA IAX Considerations           February 2010

   |      |                |                                           |
   | 0x2d | CODEC PREFS    | CODEC Negotiation                         |
   |      |                |                                           |
   | 0x2e | RR JITTER      | Received jitter, as in RFC 3550           |
   |      |                |                                           |
   | 0x2f | RR LOSS        | Received loss, as in RFC 3550             |
   |      |                |                                           |
   | 0x30 | RR PKTS        | Received frames                           |
   |      |                |                                           |
   | 0x31 | RR DELAY       | Max playout delay for received frames in  |
   |      |                | ms                                        |
   |      |                |                                           |
   | 0x32 | RR DROPPED     | Dropped frames (presumably by jitter      |
   |      |                | buffer)                                   |
   |      |                |                                           |
   | 0x33 | RR OOO         | Frames received Out of Order              |
   |      |                |                                           |
   | 0x34 | OSPTOKEN       | OSP Token Block                           |
   +------+----------------+-------------------------------------------+

                 Table 1: Information Element Definitions

2.7.  Authentication Methods

   Registry Name: IAX Authentication Methods

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.

   Description: See Section 8.6.13 of [RFC5456].

   Valid Range: 0x0001-xFFFF bitmask, values must be a power of two.

   Display format: hex.

   The following table specifies the initial assignments of IAX
   Authentication Methods:

                   +--------+--------------------------+
                   | METHOD | DESCRIPTION              |
                   +--------+--------------------------+
                   | 0x0001 | Reserved (was Plaintext) |
                   |        |                          |
                   | 0x0002 | MD5                      |
                   |        |                          |
                   | 0x0004 | RSA                      |
                   +--------+--------------------------+

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RFC 5457                 IANA IAX Considerations           February 2010

2.8.  Dialplan Status Flags

   Registry Name: IAX Dialplan Status Flags

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.

   Description: See Section 8.6.19 of [RFC5456].

   Valid Range: 0x0001-xFFFF bitmask, values must be a power of two.

   Display format: hex.

   The following table specifies the initial assignments of IAX dialplan
   status flags:

                 +--------+------------------------------+
                 | FLAG   | DESCRIPTION                  |
                 +--------+------------------------------+
                 | 0x0001 | Exists                       |
                 |        |                              |
                 | 0x0002 | Can exist                    |
                 |        |                              |
                 | 0x0004 | Non-existent                 |
                 |        |                              |
                 | 0x4000 | Retain dialtone (ignorepat)  |
                 |        |                              |
                 | 0x8000 | More digits may match number |
                 +--------+------------------------------+

2.9.  Calling Presentation

   Registry Name: IAX Calling Presentation

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.

   Description: See Section 8.6.29 of [RFC5456].

   Valid Range: 0x00-xFF.

   Display format: hex.

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RFC 5457                 IANA IAX Considerations           February 2010

   The following table specifies the initial assignments of calling
   presentation values:

              +------+--------------------------------------+
              | FLAG | PRESENTATION                         |
              +------+--------------------------------------+
              | 0x00 | Allowed user/number not screened     |
              |      |                                      |
              | 0x01 | Allowed user/number passed screen    |
              |      |                                      |
              | 0x02 | Allowed user/number failed screen    |
              |      |                                      |
              | 0x03 | Allowed network number               |
              |      |                                      |
              | 0x20 | Prohibited user/number not screened  |
              |      |                                      |
              | 0x21 | Prohibited user/number passed screen |
              |      |                                      |
              | 0x22 | Prohibited user/number failed screen |
              |      |                                      |
              | 0x23 | Prohibited network number            |
              |      |                                      |
              | 0x43 | Number not available                 |
              +------+--------------------------------------+

   NOTE: The values in this table are derived from Q.931; however,
   future values may be from other sources.

2.10.  Calling Type of Number (CALLINGTON)

   Registry Name: IAX Calling Type of Number

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.

   Description: See Section 8.6.30 of [RFC5456].

   Valid Range: 0x00-xFF.

   Display format: hex.

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RFC 5457                 IANA IAX Considerations           February 2010

   The following table specifies the initial assignments of valid
   calling type of number values:

                    +-------+-------------------------+
                    | VALUE | DESCRIPTION             |
                    +-------+-------------------------+
                    | 0x00  | Unknown                 |
                    |       |                         |
                    | 0x10  | International Number    |
                    |       |                         |
                    | 0x20  | National Number         |
                    |       |                         |
                    | 0x30  | Network Specific Number |
                    |       |                         |
                    | 0x40  | Subscriber Number       |
                    |       |                         |
                    | 0x60  | Abbreviated Number      |
                    |       |                         |
                    | 0x70  | Reserved for extension  |
                    +-------+-------------------------+

   NOTE: The values in this table are derived from Q.931; however,
   future values may be from other sources.

2.11.  IAX Transit Network Identification

   Registry Name: IAX Transit Network Identification Plan

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.

   Description: See Section 8.6.31 of [RFC5456].

   Valid Range: 0000-1111 (four bits).

   Display format: binary.

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RFC 5457                 IANA IAX Considerations           February 2010

   The following table specifies the initial assignments of IAX Calling
   Type of Number values:

                +------+----------------------------------+
                | BITS | DESCRIPTION                      |
                +------+----------------------------------+
                | 0000 | Unknown                          |
                |      |                                  |
                | 0001 | Caller Identification Code       |
                |      |                                  |
                | 0011 | Data Network Identification Code |
                +------+----------------------------------+

   NOTE: The values in this table are derived from Q.931; however,
   future values may be from other sources.

2.12.  IAX Type of Network

   Registry Name: IAX Type of Network

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.

   Description: See Section 8.6.30 of [RFC5456].

   Valid Range: 000-111 (three bits).

   Display format: binary.

   The following table specifies the initial assignments of IAX Calling
   Type of Network values:

              +------+--------------------------------------+
              | BITS | DESCRIPTION                          |
              +------+--------------------------------------+
              | 000  | User Specified                       |
              |      |                                      |
              | 010  | National Network Identification      |
              |      |                                      |
              | 011  | International Network Identification |
              +------+--------------------------------------+

   NOTE: The values in this table are derived from Q.931, however,
   future values may be from other sources.

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RFC 5457                 IANA IAX Considerations           February 2010

2.13.  Cause Codes

   Registry Name: IAX Cause Codes

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.

   Description: See Section 8.6.30 of [RFC5456].

   Valid Range: 1-255.

   Display format: decimal.

   The following table specifies the initial assignments of IAX Cause
   Code values:

   +--------+----------------------------------------------------------+
   | NUMBER | CAUSE                                                    |
   +--------+----------------------------------------------------------+
   | 1      | Unassigned/unallocated number                            |
   |        |                                                          |
   | 2      | No route to specified transit network                    |
   |        |                                                          |
   | 3      | No route to destination                                  |
   |        |                                                          |
   | 6      | Channel unacceptable                                     |
   |        |                                                          |
   | 7      | Call awarded and delivered                               |
   |        |                                                          |
   | 16     | Normal call clearing                                     |
   |        |                                                          |
   | 17     | User busy                                                |
   |        |                                                          |
   | 18     | No user response                                         |
   |        |                                                          |
   | 19     | No answer                                                |
   |        |                                                          |
   | 21     | Call rejected                                            |
   |        |                                                          |
   | 22     | Number changed                                           |
   |        |                                                          |
   | 27     | Destination out of order                                 |
   |        |                                                          |
   | 28     | Invalid number format/incomplete number                  |
   |        |                                                          |
   | 29     | Facility rejected                                        |
   |        |                                                          |
   | 30     | Response to status enquiry                               |

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RFC 5457                 IANA IAX Considerations           February 2010

   |        |                                                          |
   | 31     | Normal, unspecified                                      |
   |        |                                                          |
   | 34     | No circuit/channel available                             |
   |        |                                                          |
   | 38     | Network out of order                                     |
   |        |                                                          |
   | 41     | Temporary failure                                        |
   |        |                                                          |
   | 42     | Switch congestion                                        |
   |        |                                                          |
   | 43     | Access information discarded                             |
   |        |                                                          |
   | 44     | Requested channel not available                          |
   |        |                                                          |
   | 45     | Preempted (causes.h only)                                |
   |        |                                                          |
   | 47     | Resource unavailable, unspecified (Q.931 only)           |
   |        |                                                          |
   | 50     | Facility not subscribed (causes.h only)                  |
   |        |                                                          |
   | 52     | Outgoing call barred (causes.h only)                     |
   |        |                                                          |
   | 54     | Incoming call barred (causes.h only)                     |
   |        |                                                          |
   | 57     | Bearer capability not authorized                         |
   |        |                                                          |
   | 58     | Bearer capability not available                          |
   |        |                                                          |
   | 63     | Service or option not available (Q.931 only)             |
   |        |                                                          |
   | 65     | Bearer capability not implemented                        |
   |        |                                                          |
   | 66     | Channel type not implemented                             |
   |        |                                                          |
   | 69     | Facility not implemented                                 |
   |        |                                                          |
   | 70     | Only restricted digital information bearer capability is |
   |        | available (Q.931 only)                                   |
   |        |                                                          |
   | 79     | Service or option not available (Q.931 only)             |
   |        |                                                          |
   | 81     | Invalid call reference                                   |
   |        |                                                          |
   | 82     | Identified channel does not exist (Q.931 only)           |
   |        |                                                          |
   | 83     | A suspended call exists, but this call identity does not |
   |        | (Q.931 only)                                             |

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RFC 5457                 IANA IAX Considerations           February 2010

   |        |                                                          |
   | 84     | Call identity in use (Q.931 only)                        |
   |        |                                                          |
   | 85     | No call suspended (Q.931 only)                           |
   |        |                                                          |
   | 86     | Call has been cleared (Q.931 only)                       |
   |        |                                                          |
   | 88     | Incompatible destination                                 |
   |        |                                                          |
   | 91     | Invalid transit network selection (Q.931 only)           |
   |        |                                                          |
   | 95     | Invalid message, unspecified                             |
   |        |                                                          |
   | 96     | Mandatory information element missing (Q.931 only)       |
   |        |                                                          |
   | 97     | Message type nonexistent/not implemented                 |
   |        |                                                          |
   | 98     | Message not compatible with call state                   |
   |        |                                                          |
   | 99     | Information element nonexistent                          |
   |        |                                                          |
   | 100    | Invalid information element contents                     |
   |        |                                                          |
   | 101    | Message not compatible with call state                   |
   |        |                                                          |
   | 102    | Recovery on timer expiration                             |
   |        |                                                          |
   | 103    | Mandatory information element length error (causes.h     |
   |        | only)                                                    |
   |        |                                                          |
   | 111    | Protocol error, unspecified                              |
   |        |                                                          |
   | 127    | Internetworking, unspecified                             |
   +--------+----------------------------------------------------------+

2.14.  Encryption Methods

   Registry Name: IAX Encryption Methods

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.

   Description: See Section 8.6.34 of [RFC5456].

   Valid Range: 0x0001-x8000 bitmask, values must be a power of two.

   Display format: hex.

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RFC 5457                 IANA IAX Considerations           February 2010

   The following table specifies the initial assignments of IAX
   encryption methods:

                         +--------+-------------+
                         | METHOD | DESCRIPTION |
                         +--------+-------------+
                         | 0x0001 | AES-128     |
                         +--------+-------------+

2.15.  Media Formats

   Registry Name: IAX Media Formats

   Required Information for New Values: Name, description, and relevant
   security considerations, if any.

   Description: See Section 8.7 of [RFC5456].

   Valid Range: 0x0001-x8000 bitmask, values must be a power of two.

   Display format: hex.

   The following table specifies the initial assignments of IAX Media
   Format Values

               +------------+-----------------------------+
               | SUBCLASS   | DESCRIPTION                 |
               +------------+-----------------------------+
               | 0x00000001 | G.723.1                     |
               |            |                             |
               | 0x00000002 | GSM Full Rate               |
               |            |                             |
               | 0x00000004 | G.711 mu-law                |
               |            |                             |
               | 0x00000008 | G.711 a-law                 |
               |            |                             |
               | 0x00000010 | G.726                       |
               |            |                             |
               | 0x00000020 | IMA ADPCM                   |
               |            |                             |
               | 0x00000040 | 16-bit linear little-endian |
               |            |                             |
               | 0x00000080 | LPC10                       |
               |            |                             |
               | 0x00000100 | G.729                       |
               |            |                             |
               | 0x00000200 | Speex                       |
               |            |                             |

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RFC 5457                 IANA IAX Considerations           February 2010

               | 0x00000400 | ILBC                        |
               |            |                             |
               | 0x00000800 | G.726 AAL2                  |
               |            |                             |
               | 0x00001000 | G.722                       |
               |            |                             |
               | 0x00002000 | AMR                         |
               |            |                             |
               | 0x00010000 | JPEG                        |
               |            |                             |
               | 0x00020000 | PNG                         |
               |            |                             |
               | 0x00040000 | H.261                       |
               |            |                             |
               | 0x00080000 | H.263                       |
               |            |                             |
               | 0x00100000 | H.263p                      |
               |            |                             |
               | 0x00200000 | H.264                       |
               +------------+-----------------------------+

3.  Security Considerations

   This document defines IAX registries and as such does not raise
   security issues beyond those discussed in [RFC5456].

4.  Acknowledgments

   The author would like to thank Marc Blanchet and Michelle Cotton for
   their support and suggestions.

5.  Normative References

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.

   [RFC5456]  Spencer, M., Capouch, B., Guy, E., Ed., Miller, F., and K.
              Shumard, "IAX: Inter-Asterisk eXchange Version 2", RFC
              5456, February 2010.

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RFC 5457                 IANA IAX Considerations           February 2010

Author's Address

   Ed Guy (editor)
   Truphone
   12 Williams Rd
   Chatham, NJ  07928
   US

   Phone: +1 973 437 4519
   EMail: edguy@emcsw.com
   URI:   http://www.truphone.com/

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