Network Working Group

Internet Engineering Task Force (IETF)                          R. Jesup
Internet-Draft
Request for Comments: 8832                                       Mozilla
Intended status:
Category: Standards Track                                      S. Loreto
Expires: July 8, 2015
ISSN: 2070-1721                                                 Ericsson
                                                                M. Tuexen
                                        Muenster Tüxen
                                         Münster Univ. of Appl. Sciences
                                                         January 4, 2015
                                                          September 2020

               WebRTC Data Channel Establishment Protocol
                 draft-ietf-rtcweb-data-protocol-09.txt

Abstract

   The WebRTC framework specifies protocol support for direct
   interactive rich communication using audio, video, and data between
   two peers' web-browsers. web browsers.  This document specifies a simple protocol
   for establishing symmetric Data Channels data channels between the peers.  It uses
   a two way two-way handshake and allows sending of user data without waiting
   for the handshake to complete.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list  It represents the consensus of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid the IETF community.  It has
   received public review and has been approved for a maximum 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 six months this document, any errata,
   and how to provide feedback on it may be updated, replaced, or obsoleted by other documents obtained at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on July 8, 2015.
   https://www.rfc-editor.org/info/rfc8832.

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   document authors.  All rights reserved.

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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Protocol Overview . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Message Formats . . . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  DATA_CHANNEL_OPEN Message . . . . . . . . . . . . . . . .   4
     5.2.  DATA_CHANNEL_ACK Message  . . . . . . . . . . . . . . . .   7
   6.  Procedures  . . . . . . . . . . . . . . . . . . . . . . . . .   7
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
     8.1.  SCTP Payload Protocol Identifier  . . . . . . . . . . . .   9
     8.2.  New Standalone Registry for the DCEP  . . . . . . . . . .   9
       8.2.1.  New Message Type Registry . . . . . . . . . . . . . .   9
       8.2.2.  New Channel Type Registry . . . . . . . . . . . . . .  10
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  11
   10.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     10.1.
     9.1.  Normative References . . . . . . . . . . . . . . . . . .  11
     10.2.  Informational
     9.2.  Informative References . . . . . . . . . . . . . . . .  12
   Acknowledgements
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   The Data Channel Establishment Protocol (DCEP) is designed to
   provide, in the WebRTC Data Channel data channel context
   [I-D.ietf-rtcweb-data-channel], [RFC8831], a simple in-band in-
   band method to open for opening symmetric Data Channels. data channels.  As discussed in
   [I-D.ietf-rtcweb-data-channel],
   [RFC8831], the protocol uses the Stream Control Transmission Protocol
   (SCTP) [RFC4960] encapsulated in the Datagram Transport Layer Security
   (DTLS) as described (described in
   [I-D.ietf-tsvwg-sctp-dtls-encaps] [RFC8261]).  This allows DCEP to benefit from their
   the already standardized transport and security features. features of SCTP and
   DTLS.  DTLS 1.0 is defined in
   [RFC4347] [RFC4347], and the present latest
   version, DTLS 1.2, is defined in [RFC6347].

2.  Conventions

   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 [RFC2119].
   BCP?14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  Terminology

   This document uses the following terms:

   Association:  An SCTP association.

   Stream:  A unidirectional stream of an SCTP association.  It is
      uniquely identified by an SCTP stream identifier (0-65534).  Note:
      the
      The SCTP stream identifier 65535 is reserved due to SCTP INIT and
      INIT-ACK chunks only allowing a maximum of 65535 Streams streams to be
      negotiated (0-65534).

   Stream Identifier:  The SCTP stream identifier uniquely identifying a
      Stream.
      stream.

   Data Channel:  Two Streams streams with the same Stream Identifier, stream identifier, one in
      each direction, which are managed together.

4.  Protocol Overview

   The Data Channel Establishment Protocol is a simple, low-overhead way
   to establish bidirectional Data Channels data channels over an SCTP association
   with a consistent set of properties.

   The set of consistent properties includes:

   o

   *  reliable or unreliable message transmission.  In case of
      unreliable transmissions, the same level of unreliability is used.

   o

   *  in-order or out-of-order message delivery.

   o

   *  the priority of the Data Channel.

   o data channel.

   *  an optional label for the Data Channel.

   o data channel.

   *  an optional protocol for the Data Channel.

   o data channel.

   *  the Streams. streams.

   This protocol uses a two way two-way handshake to open a Data Channel. data channel.  The
   handshake pairs one incoming and one outgoing Stream, stream, both having the
   same Stream Identifier, stream identifier, into a single bidirectional Data Channel. data channel.
   The peer that initiates opening a Data Channel data channel selects a Stream
   Identifier stream
   identifier for which the corresponding incoming and outgoing Streams streams
   are unused and sends a DATA_CHANNEL_OPEN message on the outgoing
   Stream.
   stream.  The peer responds with a DATA_CHANNEL_ACK message on its
   corresponding outgoing Stream. stream.  Then the Data Channel data channel is open.  Data
   Channel Establishment Protocol  DCEP
   messages are sent on the same Stream stream as the user messages belonging
   to the Data Channel. data channel.  The demultiplexing is based on the SCTP payload protocol identifier Payload
   Protocol Identifier (PPID), since the Data Channel Establishment Protocol DCEP uses a specific PPID.

      |  Note: The opening side MAY send user messages before the
      |  DATA_CHANNEL_ACK is received.

   To avoid collisions where both sides try to open a Data Channel data channel with
   the same Stream Identifiers, stream identifiers, each side MUST use Streams streams with either
   even or odd Stream Identifiers stream identifiers when sending a DATA_CHANNEL_OPEN
   message.  When using SCTP over DTLS
   [I-D.ietf-tsvwg-sctp-dtls-encaps], [RFC8261], the method used to
   determine which side uses odd or even is based on the underlying DTLS
   connection role: the side acting as the DTLS client MUST use Streams streams
   with even
   Stream Identifiers, stream identifiers; the side acting as the DTLS server MUST
   use
   Streams streams with odd Stream Identifiers. stream identifiers.

      |  Note: There is no attempt to ensure uniqueness for the label;
      |  if both sides open a Data Channel data channel labeled "x" at the same time,
      |  there will be two Data Channels data channels labeled "x" - -- one on an even Stream
      |  stream pair, one on an odd pair.

   The purpose of the protocol field is to ease cross-application
   interoperation ("federation") by identifying the user data being
   passed with by means of an IANA-registered string ('WebSocket from the "WebSocket
   Subprotocol Name Registry' Registry" defined in [RFC6455]), and [RFC6455].  The field may be
   useful for homogeneous applications which that may create more than one
   type of Data Channel.  Please note data channel.  Note that there is also no attempt to ensure
   uniqueness for the protocol field.

5.  Message Formats

   Every Data Channel Establishment Protocol DCEP message starts with a one
   byte one-byte field called "Message Type" which
   that indicates the type of the message.  The corresponding values are
   managed by IANA (see Section 8.2.1).

5.1.  DATA_CHANNEL_OPEN Message

   This message is sent initially sent using the data channel on the Stream stream
   used for user messages
   using the Data Channel. messages.

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Message Type |  Channel Type |            Priority           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                    Reliability Parameter                      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |         Label Length          |       Protocol Length         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     \                                                               /
     |                             Label                             |
     /                                                               \
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     \                                                               /
     |                            Protocol                           |
     /                                                               \
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Message Type: 1 byte (unsigned integer)
      This field holds the IANA defined IANA-defined message type for the
      DATA_CHANNEL_OPEN message.  The value of this field is 0x03 0x03, as
      specified in Section 8.2.1.

   Channel Type: 1 byte (unsigned integer)
      This field specifies the type of the Data Channel data channel to be opened and
      the opened.  The
      values are managed by IANA (see Section 8.2.2):

      DATA_CHANNEL_RELIABLE (0x00):  The Data Channel data channel provides a
         reliable in-order bi-directional bidirectional communication.

      DATA_CHANNEL_RELIABLE_UNORDERED (0x80):  The Data Channel data channel provides
         a reliable unordered bi-directional bidirectional communication.

      DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT (0x01):  The Data Channel data channel
         provides a partially-reliable partially reliable in-order bi-directional bidirectional
         communication.  User messages will not be retransmitted more
         times than specified in the Reliability Parameter.

      DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT_UNORDERED (0x81):  The Data
         Channel data
         channel provides a partial partially reliable unordered bi-directional bidirectional
         communication.  User messages will not be retransmitted more
         times than specified in the Reliability Parameter.

      DATA_CHANNEL_PARTIAL_RELIABLE_TIMED (0x02):  The Data Channel data channel
         provides a partial partially reliable in-order bi-directional bidirectional
         communication.  User messages might not be transmitted or
         retransmitted after a specified life-time lifetime given in milli-
         seconds milliseconds
         in the Reliability Parameter.  This life-time lifetime starts when
         providing the user message to the protocol stack.

      DATA_CHANNEL_PARTIAL_RELIABLE_TIMED_UNORDERED (0x82):  The Data
         Channel data
         channel provides a partial partially reliable unordered bi-directional bidirectional
         communication.  User messages might not be transmitted or
         retransmitted after a specified life-time lifetime given in milli-
         seconds milliseconds
         in the Reliability Parameter.  This life-time lifetime starts when
         providing the user message to the protocol stack.

   Priority: 2 bytes (unsigned integer)
      The priority of the Data Channel data channel, as described in
      [I-D.ietf-rtcweb-data-channel]. [RFC8831].

   Reliability Parameter: 4 bytes (unsigned integer)
      For reliable Data Channels data channels, this field MUST be set to 0 on the
      sending side and MUST be ignored on the receiving side.  If a
      partial
      partially reliable Data Channel data channel with a limited number of
      retransmissions is used, this field specifies the number of
      retransmissions.  If a partial partially reliable Data Channel data channel with a
      limited lifetime is used, this field specifies the maximum
      lifetime in milliseconds.  The following table summarizes this:

   +------------------------------------------------+------------------+

     +================================================+=============+
     | Channel Type                                   | Reliability |
     |                                                |  Parameter  |
   +------------------------------------------------+------------------+
     +================================================+=============+
     | DATA_CHANNEL_RELIABLE                          |   Ignored   |
     +------------------------------------------------+-------------+
     | DATA_CHANNEL_RELIABLE_UNORDERED                |   Ignored   |
     +------------------------------------------------+-------------+
     | DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT           |  Number of  |
     |                                                |     RTX     |
     +------------------------------------------------+-------------+
     | DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT_UNORDERED |  Number of  |
     |                                                |     RTX     |
     +------------------------------------------------+-------------+
     | DATA_CHANNEL_PARTIAL_RELIABLE_TIMED            | Lifetime in |
     |                                                |      ms     |
     +------------------------------------------------+-------------+
     | DATA_CHANNEL_PARTIAL_RELIABLE_TIMED_UNORDERED  | Lifetime in |
     |                                                |      ms     |
   +------------------------------------------------+------------------+
     +------------------------------------------------+-------------+

                                 Table 1

   Label Length: 2 bytes (unsigned integer)
      The length of the label field in bytes.

   Protocol Length: 2 bytes (unsigned integer)
      The length of the protocol field in bytes.

   Label: Variable Length (sequence of characters)
      The name of the Data Channel data channel as a UTF-8 encoded string UTF-8-encoded string, as
      specified in [RFC3629].  This may be an empty string.

   Protocol: Variable Length (sequence of characters)
      If this is an empty string string, the protocol is unspecified.  If it is
      a non-empty string, it specifies a protocol registered in the
      'WebSocket
      "WebSocket Subprotocol Name Registry' Registry" created in [RFC6455].  This
      string is UTF-8 encoded encoded, as specified in [RFC3629].

5.2.  DATA_CHANNEL_ACK Message

   This message is sent in response to a DATA_CHANNEL_OPEN_RESPONSE
   message
   message.  It is sent on the stream used for user messages using the Data Channel.
   data channel.  Reception of this message tells the opener that the Data Channel
   data channel setup handshake is complete.

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Message Type |
     +-+-+-+-+-+-+-+-+

   Message Type: 1 byte (unsigned integer)
      This field holds the IANA defined IANA-defined message type for the
      DATA_CHANNEL_ACK message.  The value of this field is 0x02 0x02, as
      specified in Section 8.2.1.

6.  Procedures

   All Data Channel Establishment Protocol DCEP messages MUST be sent using ordered delivery and reliable
   transmission.  They MUST be sent on the same outgoing Stream stream as the
   user messages belonging to the corresponding Data Channel. data channel.
   Multiplexing and demultiplexing is done by using the SCTP payload protocol identifier (PPID).  Therefore Data
   Channel Establishment Protocol PPID.
   Therefore, a DCEP message MUST be sent with the assigned PPID for the
   Data Channel Establishment Protocol (see Section 8.1).  Other
   messages MUST NOT be sent using this PPID.

   The peer that initiates opening a Data Channel data channel selects a Stream
   Identifier stream
   identifier for which the corresponding incoming and outgoing Streams streams
   are unused.  If the side is acting as the DTLS client, it MUST choose
   an even
   Stream Identifier, stream identifier; if the side is acting as the DTLS server,
   it MUST choose an odd one.  It  The initiating peer fills in the
   parameters of the DATA_CHANNEL_OPEN message and sends it on the
   chosen Stream. stream.

   If a DATA_CHANNEL_OPEN message is received on an unused Stream, stream, the
   Stream Identifier
   stream identifier corresponds to the role of the peer peer, and all
   parameters in the DATA_CHANNEL_OPEN message are valid, then a
   corresponding DATA_CHANNEL_ACK message is sent on the Stream stream with the
   same Stream Identifier stream identifier as the one the DATA_CHANNEL_OPEN message was
   received on.

   If the DATA_CHANNEL_OPEN message doesn't satisfy the conditions
   above, the receiver MUST close the corresponding data channel using
   the procedure described in [RFC8831] and MUST NOT send a
   DATA_CHANNEL_ACK message in response to the received message.  This
   might occur if, for instance if example, a DATA_CHANNEL_OPEN message is received
   on an already used Stream or stream, there are any problems with parameters within
   the DATA_CHANNEL_OPEN message, the odd/even rule is violated violated, or the
   DATA_CHANNEL_OPEN message itself is not well-formed, the receiver
   MUST close the corresponding Data Channel using the procedure
   described in [I-D.ietf-rtcweb-data-channel] and MUST NOT send a
   DATA_CHANNEL_ACK message in response to the received message. well formed.  Therefore,
   receiving an SCTP stream reset stream-reset request for a Stream stream on which no
   DATA_CHANNEL_ACK message has been received indicates to the sender of
   the corresponding DATA_CHANNEL_OPEN message the failure of the Data Channel data
   channel setup procedure.  After also successfully resetting the
   corresponding outgoing Stream, stream, which concludes the Data Channel data channel
   closing initiated by the peer, a new DATA_CHANNEL_OPEN message can be
   sent on the Stream. stream.

   After the DATA_CHANNEL_OPEN message has been sent, the sender of the
   DATA_CHANNEL_OPEN that
   message MAY start sending messages containing user data without
   waiting for the reception of the corresponding DATA_CHANNEL_ACK
   message.  However, before the DATA_CHANNEL_ACK message or any other
   message has been received on a Data Channel, data channel, all other messages
   containing user data and belonging to this Data
   Channel data channel MUST be sent
   ordered, no matter whether the Data Channel data channel is ordered or not.  After
   the DATA_CHANNEL_ACK or any other message has been received on the Data Channel,
   data channel, messages containing user data MUST be sent ordered on
   ordered Data Channels data channels and MUST be sent unordered on unordered Data Channels.  Therefore data
   channels.  Therefore, receiving a message containing user data on an
   unused Stream stream indicates an error.  The  In that case, the corresponding
   Data Channel
   data channel MUST be closed closed, as described in
   [I-D.ietf-rtcweb-data-channel]. [RFC8831].

7.  Security Considerations

   The DATA_CHANNEL_OPEN messages message contains two variable length variable-length fields:
   the protocol and the label.  A receiver must be prepared to receive
   DATA_CHANNEL_OPEN messages where these field fields have the maximum length
   of 65535 bytes.  Error cases like the use of such as using inconsistent lengths of
   fields, using unknown parameter values values, or violation violating the odd/even
   rule must also be handled by closing the corresponding Data Channel. data channel.
   An end- end point must also be prepared that for the peer to open the maximum
   number of
   Data Channels. data channels.

   This protocol does not provide privacy, integrity integrity, or authentication.
   It needs to be used as part of a protocol suite that contains all
   these things.  Such a protocol suite is specified in
   [I-D.ietf-tsvwg-sctp-dtls-encaps]. [RFC8261].

   For general considerations considerations, see [I-D.ietf-rtcweb-security] [RFC8826] and
   [I-D.ietf-rtcweb-security-arch]. [RFC8827].

8.  IANA Considerations

   [NOTE to RFC-Editor:

      "RFCXXXX" is to be replaced by the RFC number you assign this
      document.

   ]

   IANA is asked to update has updated the reference of an already existing SCTP PPID
   assignment (Section 8.1) and to create created a new standalone registry with
   its own URL for the DCEP (Section 8.2) containing two new registration
   tables (Section (Sections 8.2.1 and Section 8.2.2).

8.1.  SCTP Payload Protocol Identifier

   This document uses one already registered an SCTP Payload Protocol Identifier (PPID) named
   previously registered as "WebRTC Control".  [RFC4960] creates the
   registry
   "SCTP Payload Protocol Identifiers" from registry, in which this
   identifier was assigned.  IANA is requested has updated the PPID name from "WebRTC
   Control" to update "WebRTC DCEP" and has updated the reference
   of this assignment to point to
   this document and to update the name. document.  The corresponding date should be has been kept.

   Therefore

   Therefore, this assignment should be updated to read:

           +-------------+-----------+-----------+------------+ now appears as follows:

           +=============+===========+===========+============+
           | Value       | SCTP PPID | Reference | Date       |
           +-------------+-----------+-----------+------------+
           +=============+===========+===========+============+
           | WebRTC DCEP | 50        | [RFCXXXX] RFC 8832  | 2013-09-20 |
           +-------------+-----------+-----------+------------+

                                 Table 2

8.2.  New Standalone Registry for the DCEP

   IANA is requested to create a new standalone registry (aka a webpage)
   with its own URL for has created the Data Channel Establishment Protocol (DCEP).
   The title should be "Data Channel Establishment Protocol (DCEP)
   Parameters".
   Parameters" registry.  It will contain contains the two tables as described provided in
   Section
   Sections 8.2.1 and Section 8.2.2.

8.2.1.  New Message Type Registry

   IANA is requested to create a new registration table has created the "Message Type
   Registry" Types" registry for the Data Channel Establishment Protocol (DCEP) DCEP to manage the one byte
   one-byte "Message Type" field in DCEP messages (see Section 5).  This
   registration table should be part is a subregistry of the registry described in
   Section 8.2.

   The assignment of new message types is done through an RFC required Required
   action, as defined in [RFC5226]. [RFC8126].  Documentation of the new message
   type types
   MUST contain the following information:

   1.  A name for the new message type; type.

   2.  A detailed procedural description of the use of messages with the
       new how each message type is
       used with within the operation of the Data Channel Establishment
       Protocol.

   Initially the DCEP.

   The following values need to be registered:

               +-------------------+-----------+-----------+ are the inital registrations:

               +===================+===========+===========+
               | Name              | Type      | Reference |
               +-------------------+-----------+-----------+
               +===================+===========+===========+
               | Reserved          | 0x00      | [RFCXXXX] RFC 8832  |
               +-------------------+-----------+-----------+
               | Reserved          | 0x01      | [RFCXXXX] RFC 8832  |
               +-------------------+-----------+-----------+
               | DATA_CHANNEL_ACK  | 0x02      | [RFCXXXX] RFC 8832  |
               +-------------------+-----------+-----------+
               | DATA_CHANNEL_OPEN | 0x03      | [RFCXXXX] RFC 8832  |
               +-------------------+-----------+-----------+
               | Unassigned        | 0x04-0xfe |           |
               +-------------------+-----------+-----------+
               | Reserved          | 0xff      | [RFCXXXX] RFC 8832  |
               +-------------------+-----------+-----------+

   Please note

                                  Table 3

   Note that the values 0x00 and 0x01 are reserved to avoid interoperability
   problems, since they have been used in earlier draft versions of the
   document.  The value 0xff has been reserved for future extensibility.
   The range of possible values is from 0x00 to 0xff.

8.2.2.  New Channel Type Registry

   IANA is requested to create a new registration table has created the "Channel Type
   Registry" Types" registry for the Data Channel Establishment Protocol DCEP to manage the
   one byte
   one-byte "Channel Type" field in DATA_CHANNEL_OPEN messages (see
   Section 5.1).  This registration table should be part of is a subregistry within the
   registry described in Section 8.2.

   The assignment of new message types is done through an RFC required Required
   action, as defined in [RFC5226]. [RFC8126].  Documentation of the new Channel
   Type Types
   MUST contain the following information:

   1.  A name for the new Channel Type; Type.

   2.  A detailed procedural description of the user message handling
       for Data Channels data channels using this new Channel Type.

   Please note that if

   If new Channel Types support ordered and unordered message delivery,
   the high order high-order bit MUST be used to indicate whether or not the
   message delivery is unordered or not.

   Initially the unordered.

   The following values need to be registered:

   +------------------------------------------------+------+-----------+ are the initial registrations:

   +================================================+======+===========+
   | Name                                           | Type | Reference |
   +------------------------------------------------+------+-----------+
   +================================================+======+===========+
   | DATA_CHANNEL_RELIABLE                          | 0x00 | [RFCXXXX] RFC 8832  |
   +------------------------------------------------+------+-----------+
   | DATA_CHANNEL_RELIABLE_UNORDERED                | 0x80 | [RFCXXXX] RFC 8832  |
   +------------------------------------------------+------+-----------+
   | DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT           | 0x01 | [RFCXXXX] RFC 8832  |
   +------------------------------------------------+------+-----------+
   | DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT_UNORDERED | 0x81 | [RFCXXXX] RFC 8832  |
   +------------------------------------------------+------+-----------+
   | DATA_CHANNEL_PARTIAL_RELIABLE_TIMED            | 0x02 | [RFCXXXX] RFC 8832  |
   +------------------------------------------------+------+-----------+
   | DATA_CHANNEL_PARTIAL_RELIABLE_TIMED_UNORDERED  | 0x82 | [RFCXXXX] RFC 8832  |
   +------------------------------------------------+------+-----------+
   | Reserved                                       | 0x7f | [RFCXXXX] RFC 8832  |
   +------------------------------------------------+------+-----------+
   | Reserved                                       | 0xff | [RFCXXXX] RFC 8832  |
   +------------------------------------------------+------+-----------+
   | Unassigned                                     | rest |           |
   +------------------------------------------------+------+-----------+

   Please note that the values

                                  Table 4

   Values 0x7f and 0xff have been reserved for future extensibility.
   The range of possible values is from 0x00 to 0xff.

9.  Acknowledgments

   The authors wish to thank Harald Alvestrand, Richard Barnes, Adam
   Bergkvist, Spencer Dawkins, Barry Dingle, Stefan Haekansson, Cullen
   Jennings, Paul Kyzivat, Doug Leonard, Alexey Melnikov, Pete Resnick,
   Irene Ruengeler, Randall Stewart, Peter Thatcher, Martin Thompson,
   Justin Uberti, and many others for their invaluable comments.

10.  References

10.1.

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997. 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [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>.

   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
              10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November 2003.
              2003, <https://www.rfc-editor.org/info/rfc3629>.

   [RFC4347]  Rescorla, E. and N. Modadugu, "Datagram Transport Layer
              Security", RFC 4347, DOI 10.17487/RFC4347, April 2006. 2006,
              <https://www.rfc-editor.org/info/rfc4347>.

   [RFC4960]  Stewart, R., Ed., "Stream Control Transmission Protocol",
              RFC 4960, DOI 10.17487/RFC4960, September 2007.

   [RFC5226]  Narten, T. 2007,
              <https://www.rfc-editor.org/info/rfc4960>.

   [RFC8126]  Cotton, M., Leiba, B., and H. Alvestrand, T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 5226,
              May 2008. 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

   [RFC6347]  Rescorla, E. and N. Modadugu, "Datagram Transport Layer
              Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
              January 2012.

   [I-D.ietf-tsvwg-sctp-dtls-encaps] 2012, <https://www.rfc-editor.org/info/rfc6347>.

   [RFC8261]  Tuexen, M., Stewart, R., Jesup, R., and S. Loreto, "DTLS
              "Datagram Transport Layer Security (DTLS) Encapsulation of
              SCTP Packets", draft-ietf-tsvwg-sctp-
              dtls-encaps-07 (work in progress), December 2014.

   [I-D.ietf-rtcweb-data-channel] RFC 8261, DOI 10.17487/RFC8261, November
              2017, <https://www.rfc-editor.org/info/rfc8261>.

   [RFC8831]  Jesup, R., Loreto, S., and M. Tuexen, Tüxen, "WebRTC Data
              Channels", draft-ietf-rtcweb-data-channel-12 (work in
              progress), RFC 8831, DOI 10.17487/RFC8831, September 2014.

10.2.  Informational 2020,
              <https://www.rfc-editor.org/info/rfc8831>.

9.2.  Informative References

   [RFC6455]  Fette, I. and A. Melnikov, "The WebSocket Protocol",
              RFC 6455, DOI 10.17487/RFC6455, December 2011.

   [I-D.ietf-rtcweb-security] 2011,
              <https://www.rfc-editor.org/info/rfc6455>.

   [RFC8826]  Rescorla, E., "Security Considerations for WebRTC", draft-
              ietf-rtcweb-security-07 (work in progress), July 2014.

   [I-D.ietf-rtcweb-security-arch]
              RFC 8826, DOI 10.17487/RFC8826, September 2020,
              <https://www.rfc-editor.org/info/rfc8826>.

   [RFC8827]  Rescorla, E., "WebRTC Security Architecture", draft-ietf-
              rtcweb-security-arch-10 (work in progress), July 2014. RFC 8827,
              DOI 10.17487/RFC8827, September 2020,
              <https://www.rfc-editor.org/info/rfc8827>.

Acknowledgements

   The authors wish to thank Harald Alvestrand, Richard Barnes, Adam
   Bergkvist, Spencer Dawkins, Barry Dingle, Stefan Haekansson, Cullen
   Jennings, Paul Kyzivat, Doug Leonard, Alexey Melnikov, Pete Resnick,
   Irene Rüngeler, Randall Stewart, Peter Thatcher, Martin Thompson,
   Justin Uberti, and many others for their invaluable comments.

Authors' Addresses

   Randell Jesup
   Mozilla
   US
   United States of America

   Email: randell-ietf@jesup.org

   Salvatore Loreto
   Ericsson
   Hirsalantie 11
   FI-02420 Jorvas  02420
   FI
   Finland

   Email: salvatore.loreto@ericsson.com

   Michael Tuexen
   Muenster Tüxen
   Münster University of Applied Sciences
   Stegerwaldstrasse 39
   Steinfurt
   48565
   DE  Steinfurt
   Germany

   Email: tuexen@fh-muenster.de