CLUE Protocol Data Channel
draft-ietf-clue-datachannel-03
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (clue WG) | |
|---|---|---|---|
| Author | Christer Holmberg | ||
| Last updated | 2014-11-20 | ||
| Replaces | draft-holmberg-clue-datachannel | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text xml htmlized pdfized bibtex | ||
| Reviews |
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| Stream | WG state | WG Document | |
| Document shepherd | Paul Kyzivat | ||
| IESG | IESG state | I-D Exists | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-clue-datachannel-03
CLUE Working Group C. Holmberg
Internet-Draft Ericsson
Intended status: Standards Track November 20, 2014
Expires: May 24, 2015
CLUE Protocol Data Channel
draft-ietf-clue-datachannel-03
Abstract
This document defines how to use the WebRTC Data Channel mechanism,
together with the Data Channel Establishment Protocol (DCEP) and the
SDP-based "SCTP over DTLS" data channel negotiation mechanism, in
order to establish a data channel, referred to as CLUE Data Channel,
for transporting CLUE protocol messages between two CLUE entities.
The document defines the SCTP considerations specific to a CLUE Data
Channel, the SDP Media Description- and SDP dcmap attribute values,
and the DCEP procedures for opening, a CLUE Data Channel.
Details and procedures associated with the CLUE protocol, and the SDP
Offer/Answer procedures for negotiating a CLUE data channel, are
outside the scope of this document.
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 of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents 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 May 24, 2015.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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
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include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. CLUE Data Channel . . . . . . . . . . . . . . . . . . . . . . 4
3.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. SDP Considerations . . . . . . . . . . . . . . . . . . . 4
3.2.1. General . . . . . . . . . . . . . . . . . . . . . . . 4
3.2.2. SDP Media Description Fields . . . . . . . . . . . . 4
3.2.3. SDP sctpmap Attribute . . . . . . . . . . . . . . . . 5
3.2.4. SDP dcpmap Attribute . . . . . . . . . . . . . . . . 5
3.2.5. SDP dcsa Attribute . . . . . . . . . . . . . . . . . 5
3.2.6. Example . . . . . . . . . . . . . . . . . . . . . . . 5
3.3. Data Channel Establishment Protocol (DCEP) Considerations 6
3.3.1. General . . . . . . . . . . . . . . . . . . . . . . . 6
3.3.2. Open CLUE Data Channel . . . . . . . . . . . . . . . 6
3.3.3. Close CLUE Data Channel . . . . . . . . . . . . . . . 6
3.3.4. SCTP Association Failure . . . . . . . . . . . . . . 7
3.4. SCTP Considerations . . . . . . . . . . . . . . . . . . . 7
3.4.1. SCTP Payload Protocol Identifier (PPID) . . . . . . . 7
3.4.2. Reliability . . . . . . . . . . . . . . . . . . . . . 7
3.4.3. Order . . . . . . . . . . . . . . . . . . . . . . . . 8
3.4.4. Stream Reset . . . . . . . . . . . . . . . . . . . . 8
3.4.5. SCTP Multihoming . . . . . . . . . . . . . . . . . . 8
4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 8
7. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 8
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Normative References . . . . . . . . . . . . . . . . . . 10
8.2. Informative References . . . . . . . . . . . . . . . . . 11
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
This document defines how to use the WebRTC Data Channel mechanism
[I-D.ietf-rtcweb-data-channel], together with the Data Channel
Establishment Protocol (DCEP) [I-D.ietf-rtcweb-data-protocol] and the
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SDP-based "SCTP over DTLS" data channel negotiation mechanism [add-
ref], in order to establish a data channel, referred to as CLUE Data
Channel, for transporting CLUE protocol [I-D.ietf-clue-protocol]
messages between CLUE entities.
The document defines the SCTP considerations specific to a CLUE Data
Channel, the SDP Media Description- and SDP dcmap attribute values,
and the DCEP procedures for opening, a CLUE Data Channel.
Details and procedures associated with the CLUE protocol, and the SDP
Offer/Answer [RFC3264] procedures for negotiating a CLUE data
channel, are outside the scope of this document.
2. Conventions
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 BCP 14, RFC 2119
[RFC2119].
WebRTC Data Channel refers to a SCTPoDTLS association
[I-D.ietf-tsvwg-sctp-dtls-encaps] that is used to transport non-media
data between two entities, according to the procedures in
[I-D.ietf-rtcweb-data-channel].
CLUE Data Channel refers to a WebRTC Data Channel
[I-D.ietf-rtcweb-data-channel], with a specific set of SCTP
characteristics, and usage of the Data Channel Establishment Protocol
(DCEP) [I-D.ietf-rtcweb-data-protocol] in order to open a WebRTC Data
Channel for the purpose of transporting CLUE protocol
[I-D.ietf-clue-protocol] messages between two CLUE entities.
CLUE entity refers to a SIP User Agent (UA) [RFC3261] that supports
the CLUE Data Channel and the CLUE protocol.
CLUE session refers to a SIP session [RFC3261] between to SIP UAs,
where a CLUE Data Channel, associated with the SIP session, has been
established between the SIP UAs.
[RFC4960] defines an SCTP stream as a unidirectional logical channel
established from one to another associated SCTP endpoint, within
which all user messages are delivered in sequence except for those
submitted to the unordered delivery service.
[RFC4960] defines an SCTP identifier as a unsigned integer, which
identifies a SCTP stream.
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3. CLUE Data Channel
3.1. General
This section describes the realization of a CLUE Data Channel. This
includes a set of SCTP characteristics specific to a CLUE Data
Channel, the usage of the SDP-based "SCTP over DTLS" data channel
negotiation mechanism to describe a CLUE data channel in SDP, and the
usage of the Data Channel Establishment Protocol (DCEP)
[I-D.ietf-rtcweb-data-protocol] in order to open a WebRTC Data
Channel for the purpose of transporting CLUE protocol
[I-D.ietf-clue-protocol] messages between two CLUE entities.
As described in [I-D.ietf-rtcweb-data-channel], the SCTP streams
realizing a WebRTC Data Channel must be associated with the same SCTP
association. In addition, both SCTP streams realizing the WebRTC
Data Channel must use the same SCTP stream identifier value. These
rules also apply to a CLUE Data Channel.
Within a given CLUE session, a CLUE entity MUST use a single CLUE
Data Channel for transport of all CLUE messages towards its peer.
3.2. SDP Considerations
3.2.1. General
This section defines how to construct the SDP Media Description ("m="
line), and the associated SDP dcmap attribute, used to describe a
CLUE data channel in SDP.
[I-D.ietf-clue-protocol] describes the SDP Offer/Answer procedures
for negotiating a CLUE session, including the CLUE controlled media
channels and the CLUE data channel.
3.2.2. SDP Media Description Fields
The field values of the "m=" line for the SCTPoDTLS association are
set as following:
+---------------+-----------------+-------------+-----------------+
| media | port | proto | fmt |
+---------------+-----------------+-------------+-----------------+
| "application" | DTLS port value | "DTLS/SCTP" | SCTP port value |
+---------------+-----------------+-------------+-----------------+
Table 1: SDP "proto" field values
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3.2.3. SDP sctpmap Attribute
The field values of the SDP sctpmap attribute, associated with the
"m=" line describing the SCTPoDTLS association, are set as following:
+----------------------------+----------------------+
| sctpmap-number | app |
+----------------------------+----------------------+
| fmt value of the "m=" line | "webrtc-datachannel" |
+----------------------------+----------------------+
Table 2: SDP sctpmap attribute values
3.2.4. SDP dcpmap Attribute
The SDP dcmap attribute [I-D.ejzak-mmusic-data-channel-sdpneg] values
for the CLUE data channel, associated with the "m=" line describing
the SCTPoDTLS, are set as following:
+------------+------------+--------+----------+----------+----------+
| dcmap- | subprotoco | label- | ordering | maxretr- | maxtime- |
| stream-id | l-opt | opt | -opt | opt | opt |
+------------+------------+--------+----------+----------+----------+
| Value of | "CLUE" | "CLUE | Not appl | Not appl | Not appl |
| the SCTP | | Data C | icable | icable | icable |
| stream | | hannel | | | |
| used to | | " | | | |
| realize | | | | | |
| the CLUE | | | | | |
| data | | | | | |
| channel | | | | | |
+------------+------------+--------+----------+----------+----------+
Table 3: SDP dcmap attribute values
3.2.5. SDP dcsa Attribute
The SDP dcsa attribute [I-D.ejzak-mmusic-data-channel-sdpneg] is not
used to describe a CLUE data channel.
3.2.6. Example
m=application 54111 SCTP/DTLS webrtc-datachannel
a=dcmap:2 subprotocol="CLUE";label="CLUE Data Channel"
Figure 1: SDP Media Description for a CLUE Data Channel
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3.3. Data Channel Establishment Protocol (DCEP) Considerations
3.3.1. General
A CLUE entity MUST support the Data Channel Establishment Protocol
(DCEP) [I-D.ietf-rtcweb-data-channel], which can be used in order to
open a WebRTC Data Channel.
This section describes how to open and close a CLUE data channel
using DCEP.
NOTE: This document does not define any other mechanism for opening a
CLUE Data Channel, but such might be defined in future
specifications.
3.3.2. Open CLUE Data Channel
Once the SCTP association, to be used to realized the CLUE Data
Channel, has been established, the offerer [RFC3264] is responsible
for opening the CLUE Data Channel. If DCEP is used, the offerer MUST
send a DCEP DATA_CHANNEL_OPEN message
[I-D.ietf-rtcweb-data-protocol]. The value of the 'protocol' field
MUST be "CLUE". The value of the 'channel type' MUST be
'DATA_CHANNEL_RELIABLE'.
NOTE: A new 'protocol' value for CLUE needs to be registered with
IANA in the 'Protocol Registry' defined by
[I-D.ietf-rtcweb-data-protocol].
Once the offerer has received the associated DCEP DATA_CHANNEL_ACK
message [I-D.ietf-rtcweb-data-protocol], the CLUE Data channel has
been opened.
If the offerer receives a DCEP DATA_CHANNEL_OPEN message, for the
purpose of opening a CLUE Data Channel, the offerer MUST reset the
SCTP stream, in order to prevent two CLUE Data Channels from being
established within the same CLUE session. The offerer MUST NOT send
a DCEP DATA_CHANNEL_ACK message.
3.3.3. Close CLUE Data Channel
DCEP [I-D.ietf-rtcweb-data-protocol] does not define a message for
closing a WebRTC Data Channel. As described in
[I-D.ietf-rtcweb-data-protocol], in order to close a CLUE Data
Channel, a SCTP reset message is sent, in order to close the SCTP
stream associated with the CLUE Data Channel. The SCTP association,
and WebRTC Data Channels associated with other SCTP streams, are not
affected by the SCTP reset message.
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3.3.4. SCTP Association Failure
In case of SCTP association failure, the offerer is responsible for
trying to re-establish the SCTP association (including sending a new
SDP offer, if needed). Once the SCTP association has been
successfully re-established, the offerer is responsible for sending a
DCEP DATA_CHANNEL_OPEN message.
3.4. SCTP Considerations
3.4.1. SCTP Payload Protocol Identifier (PPID)
As described in [I-D.ietf-rtcweb-data-protocol], the PPID value 50 is
used when sending a DCEP message on a WebRTC Data Channel.
A CLUE entity MUST use the PPID value 51 when sending a CLUE message
on a CLUE Data Channel.
NOTE: As described in [I-D.ietf-rtcweb-data-channel], the PPID value
51 indicates that the SCTP message contains data encoded in a UTF-8
format. The PPID value 51 does not indicate what application
protocol is transported in a WebRTC Data Channel, only the format in
which the data is encoded.
+----------+------------+
| Protocol | PPID Value |
+----------+------------+
| DCEP | 50 |
| CLUE | 51 |
+----------+------------+
Table 4: CLUE Data Channel PPID Values
3.4.2. Reliability
The usage of SCTP for the CLUE Data Channel ensures reliable
transport of CLUE protocol [I-D.ietf-clue-protocol] messages.
A CLUE entity MUST NOT use the partial reliability and limited
retransmission extensions defined in [RFC3758].
NOTE: [I-D.ietf-rtcweb-data-channel] requires the support of the
partial reliability extension defined in [RFC3758]. This is not
needed for a CLUE Data Channel, as messages are required to always be
sent reliably. [I-D.ietf-rtcweb-data-channel] also mandates support
of the limited retransmission policy defined in
[I-D.ietf-tsvwg-sctp-prpolicies].
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3.4.3. Order
A CLUE entity MUST use the ordered delivery SCTP service, as
described in section 6.6 of [RFC4960].
3.4.4. Stream Reset
A CLUE entity MUST support the stream reset extension defined in
[RFC6525].
The dynamic address reconfiguration extension defined in [RFC5061]
MUST be used to signal the support of the stream reset extension
defined in [RFC6525]. Other features of [RFC5061] MUST NOT be used.
3.4.5. SCTP Multihoming
SCTP multihoming cannot be used for a CLUE Data Channel.
NOTE: SCTPoDTLS does not support SCTP multihoming.
4. Security Considerations
This specification does not introduce new security considerations, in
addition to those defined in [I-D.ietf-rtcweb-data-channel] and
[I-D.ietf-rtcweb-data-protocol]. Security considerations associated
with the CLUE protocol are defined in [I-D.ietf-clue-protocol].
5. IANA Considerations
[RFC EDITOR NOTE: Please replace RFC-XXXX with the RFC number of this
document.]
6. Acknowledgments
Thanks to Paul Kyzivat and Christian Groves for comments on the
document.
7. Change Log
[RFC EDITOR NOTE: Please remove this section when publishing]
Changes from draft-ietf-clue-datachannel-02
o SDP m- line example fixed.
o OPEN ISSUE #1 closed.
o - It was agreed (IETF#91) to use draft-ejzak-mmusic-data-channel-
sdpneg, as it was adopted as a WG item in MMUSIC.
o - Details for draft-ejzak-mmusic-data-channel-sdpneg usage added.
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o SDP Offer/Answer procedures removed, as they will be defined in
the CLUE protocol draft.
o References updated.
Changes from draft-ietf-clue-datachannel-01
o Support of interleaving "MUST"->"SHOULD".
o Example updated.
o Reference update.
Changes from draft-ietf-clue-datachannel-00
o SDP Offer/Answer procedures structures according to RFC 3264.
o Reference update.
Changes from draft-holmberg-clue-datachannel-04
o Draft submitted as draft-ietf-clue-data-channel-00.
o Editorial nits fixed.
o Changes based on comments from Paul Kyzivat (http://www.ietf.org/
mail-archive/web/clue/current/msg03559.html).
o - Proto value fixed.
o - Explicit text that the partial reliability and limited
retransmission policies MUST NOT be used.
o - Added open issue on whether the DCEP 'protocol' field value for
CLUE should contain a version number.
o - Removed paragraph saying that an offerer must not insert more
than one m- line describing an SCTPoDTLS association to be used to
realize a CLUE Data Channel, as the draft already states that only
one CLUE Data Channel per CLUE session shall be opened.
o - Added reference to draft-ietf-rtcweb-data-protocol regarding
details on reseting SCTP streams.
o - Added text saying that the value of the DCEP 'channel type' MUST
be DATA_CHANNEL_RELIABLE.
o - Clarified that DCEP must be supported, and used in the absence
of another mechanism for opening a CLUE Data Channel.
Changes from draft-holmberg-clue-datachannel-03
o Procedures updated, based on WG agreement (IETF#89) to use DCEP
for the CLUE data channel.
o Procedures updated, based on WG agreement (IETF#89) that offerer
is responsible for sending DCEP DATA_CHANNEL_OPEN.
o Editorial changes, and alignments caused by changes in referenced
specifications.
Changes from draft-holmberg-clue-datachannel-02
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o PPID value for CLUE messages added
o References updated
Changes from draft-holmberg-clue-datachannel-01
o More text added
Changes from draft-holmberg-clue-datachannel-00
o Editorial corrections based on comments from Paul K
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261,
June 2002.
[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
with Session Description Protocol (SDP)", RFC 3264, June
2002.
[RFC4960] Stewart, R., "Stream Control Transmission Protocol", RFC
4960, September 2007.
[RFC5061] Stewart, R., Xie, Q., Tuexen, M., Maruyama, S., and M.
Kozuka, "Stream Control Transmission Protocol (SCTP)
Dynamic Address Reconfiguration", RFC 5061, September
2007.
[RFC6525] Stewart, R., Tuexen, M., and P. Lei, "Stream Control
Transmission Protocol (SCTP) Stream Reconfiguration", RFC
6525, February 2012.
[I-D.ietf-clue-protocol]
Presta, R. and S. Romano, "CLUE protocol", draft-ietf-
clue-protocol-02.txt (work in progress), October 2014.
[I-D.ietf-tsvwg-sctp-dtls-encaps]
Tuexen, M., Stewart, R., Jesup, R., and S. Loreto, "DTLS
Encapsulation of SCTP Packets", draft-ietf-tsvwg-sctp-
dtls-encaps-06.txt (work in progress), November 2014.
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[I-D.ietf-rtcweb-data-channel]
Jesup, R., Loreto, S., and M. Tuexen, "WebRTC Data
Channels", draft-ietf-rtcweb-data-channel-12.txt (work in
progress), September 2014.
[I-D.ietf-rtcweb-data-protocol]
Jesup, R., Loreto, S., and M. Tuexen, "WebRTC Data Channel
Establishment Protocol", draft-ietf-rtcweb-data-protocol-
08.txt (work in progress), September 2014.
[I-D.ietf-tsvwg-sctp-prpolicies]
Tuexen, M., Seggelmann, R., Stewart, R., and S. Loreto,
"Additional Policies for the Partial Reliability Extension
of the Stream Control Transmission Protocol", draft-ietf-
tsvwg-sctp-prpolicies-05.txt (work in progress), November
2014.
[I-D.ejzak-mmusic-data-channel-sdpneg]
Drage, K., Makaraju, R., Ejzak, R., and J. Marcon, "SDP-
based WebRTC data channel negotiation", draft-ejzak-
mmusic-data-channel-sdpneg-02.txt (work in progress),
October 2014.
8.2. Informative References
[RFC3758] Stewart, R., Ramalho, M., Xie, Q., Tuexen, M., and P.
Conrad, "Stream Control Transmission Protocol (SCTP)
Partial Reliability Extension", RFC 3758, May 2004.
Author's Address
Christer Holmberg
Ericsson
Hirsalantie 11
Jorvas 02420
Finland
Email: christer.holmberg@ericsson.com
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