Session Description Protocol (SDP) WebSocket Connection URI Attribute
draft-ram-bfcpbis-sdp-ws-uri-01
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
|
|
|---|---|---|---|
| Authors | Ram R , Gonzalo Salgueiro | ||
| Last updated | 2015-10-18 | ||
| Replaced by | draft-ietf-bfcpbis-sdp-ws-uri, RFC 8124 | ||
| RFC stream | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ram-bfcpbis-sdp-ws-uri-01
BFCPBIS Working Group Ram. Ravindranath
Internet-Draft G. Salgueiro
Intended status: Standards Track Cisco
Expires: April 20, 2016 October 18, 2015
Session Description Protocol (SDP) WebSocket Connection URI Attribute
draft-ram-bfcpbis-sdp-ws-uri-01
Abstract
The WebSocket protocol enables bidirectional real-time communication
between clients and servers in web-based applications. This document
specifies extensions to Session Description Protocol (SDP) for
application protocols using WebSocket as a transport.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 20, 2016.
Copyright Notice
Copyright (c) 2015 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. SDP Considerations . . . . . . . . . . . . . . . . . . . . . 3
3.1. 'ws-uri' SDP Media Attribute . . . . . . . . . . . . . . 3
3.2. 'wss-uri' SDP Media Attribute . . . . . . . . . . . . . . 3
3.3. Example Usage of 'ws-uri' SDP Attribute . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5.1. Registration of the 'ws-uri' SDP media attribute . . . . 5
5.2. Registration of the 'wss-uri' SDP media attribute . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . 6
7.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
The WebSocket protocol [RFC6455] enables bidirectional message
exchange between clients and servers on top of a persistent TCP
connection (optionally secured with Transport Layer Security (TLS)
[RFC5246]). The initial protocol handshake makes use of Hypertext
Transfer Protocol (HTTP) [RFC2616] semantics, allowing the WebSocket
protocol to reuse existing HTTP infrastructure.
Modern web browsers include a WebSocket client stack compliant with
the WebSocket API [WS-API] as specified by the W3C. It is expected
that other client applications (e.g., those running on personal
computers, mobile devices, etc.) will also make a WebSocket client
stack available. Several specifications have been written that
define how different applications can use a WebSocket subprotocol as
a reliable transport mechanism.
For example, [RFC7118] defines WebSocket subprotocol as a reliable
transport mechanism between Session Initiation Protocol
(SIP)[RFC3261] entities to enable use of SIP in web-oriented
deployments. Additionally, [I-D.pd-dispatch-msrp-websocket] defines
a new WebSocket sub-protocol as a reliable transport mechanism
between Message Session Relay Protocol (MSRP) clients and relays.
[RFC7395] defines a WebSocket subprotocol for the Extensible
Messaging and Presence Protocol (XMPP). Similarly,
[I-D.ietf-bfcpbis-bfcp-websocket] defines a WebSocket sub-protocol as
a reliable transport mechanism between Binary Floor Control Protocol
(BFCP) [I-D.ietf-bfcpbis-rfc4582bis] entities to enable usage of BFCP
in new scenarios.
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As defined in Section 3 of [RFC2818], when using Secure WebSockets
the Canonical Name (CNAME) of the Secure Sockets Layer (SSL)
[RFC6101] certificate MUST match the WebSocket connection URI host.
While it is possible to generate self-signed certificates with
Internet Providers (IPs) as CNAME, in most cases it is not viable for
certificates signed by well known authorities. Thus, there is a need
to indicate the connection URI for the WebSocket Client. For
applications that use Session Description Protocol (SDP) [RFC4566] to
negotiate, the connection URI can be indicated by means of an SDP
attribute. This specification defines new SDP attributes to indicate
the connection URI for the WebSocket client. Applications that use
SDP for negotiation and WebSocket as a transport protocol can use
this specification to advertise the WebSocket client connection URI.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
3. SDP Considerations
3.1. 'ws-uri' SDP Media Attribute
Applications that use SDP for negotiation and also use WebSocket as a
transport protocol MAY indicate the connection URI for the WebSocket
Client via a new SDP a= attribute defined in this section. The
Augmented Backus-Naur Form (ABNF) syntax (as described in [RFC5234])
of this new attribute is defined as follows:
ws-uri = "a=ws-uri:" ws-URI
Where ws-URI is defined in Section 3 of [RFC6455].
This new attribute MUST be a media level attribute and SHALL appear
in any of the media lines. When the 'ws-uri' attribute is present in
the media section of the SDP, the IP and port information provided in
the 'c' lines SHALL be ignored and the full URI SHALL be used instead
to open the WebSocket connection. The port provided in the 'm' line
SHALL be ignored too, as the a=ws-uri SHALL provide port number when
needed.
3.2. 'wss-uri' SDP Media Attribute
Applications that use SDP for negotiation and also use secure
WebSocket as a transport protocol TLS MAY indicate the connection URI
for the WebSocket Client via a new SDP a= attribute defined in this
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section. The Augmented Backus-Naur Form (ABNF) syntax (as described
in [RFC5234]) of this new attribute is defined as follows:
wss-uri = "a=wss-uri:" wss-URI
Where wss-URI is defined in Section 3 of [RFC6455].
This new attribute MUST be a media level attribute and SHALL appear
in any of the media lines. When the 'wss-uri' attribute is present
in the media section of the SDP, the IP and port information provided
in the 'c' lines SHALL be ignored and the full URI SHALL be used
instead to open the WebSocket connection. The port provided in the
'm' line SHALL be ignored too, as the a=wss-uri SHALL provide port
number when needed.
3.3. Example Usage of 'ws-uri' SDP Attribute
The following are examples of 'm' lines for BFCP over WebSocket
connection:
Offer (browser):
m=application 9 TCP/WSS/BFCP *
a=setup:active
a=connection:new
a=floorctrl:c-only
m=audio 55000 RTP/AVP 0
m=video 55002 RTP/AVP 31
Answer (server):
m=application 50000 TCP/WSS/BFCP *
a=setup:passive
a=connection:new
a=ws-uri:wss://bfcp-ws.example.com?token=3170449312
a=floorctrl:s-only
a=confid:4321
a=userid:1234
a=floorid:1 m-stream:10
a=floorid:2 m-stream:11
m=audio 50002 RTP/AVP 0
a=label:10
m=video 50004 RTP/AVP 31
a=label:11
4. Security Considerations
An attacker may attempt to add, modify, or remove 'a=ws-uri' or
'a=wss-uri' attribute from a session description. This could result
in an application behaving undesirably. Consequently, it is strongly
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RECOMMENDED that integrity protection be applied to the SDP session
descriptions. For session descriptions carried in SIP [RFC3261], S/
MIME is the natural choice to provide such end-to-end integrity
protection.
It is also RECOMMENDED that the application signaling traffic being
transported over a WebSocket communication session be protected by
using a secure WebSocket connection (using TLS [RFC5246] over TCP).
5. IANA Considerations
5.1. Registration of the 'ws-uri' SDP media attribute
This section instructs the IANA to register the following SDP att-
field under the Session Description Protocol (SDP) Parameters
registry:
Contact name Gonzalo Salgueiro
Attribute name ws-uri
Long-form attribute name Websocket Connection URI
Type of attribute Media level
Subject to charset No
Purpose of attribute The 'ws-uri' attribute is intended to be used
as a connection URI for opening the WebSocket connection.
Allowed attribute values A ws-URI as defined in [RFC6455]
5.2. Registration of the 'wss-uri' SDP media attribute
This section instructs the IANA to register the following SDP att-
field under the Session Description Protocol (SDP) Parameters
registry:
Contact name Gonzalo Salgueiro
Attribute name wss-uri
Long-form attribute name Websocket Connection URI over Secure
Transport
Type of attribute Media level
Subject to charset No
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Purpose of attribute The 'wss-uri' attribute is intended to be used
as a connection URI for opening the WebSocket connection over a
secure transport.
Allowed attribute values A wss-URI as defined in [RFC6455]
6. Acknowledgements
Thanks to Christer Holmberg for raising the need for a BFCP-
independent SDP attribute for WebSocket Connection URI.
7. References
7.1. 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,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<http://www.rfc-editor.org/info/rfc5234>.
[RFC6455] Fette, I. and A. Melnikov, "The WebSocket Protocol",
RFC 6455, DOI 10.17487/RFC6455, December 2011,
<http://www.rfc-editor.org/info/rfc6455>.
7.2. Informative References
[I-D.ietf-bfcpbis-bfcp-websocket]
Pascual, V., Roman, A., Cazeaux, S., Salgueiro, G., R, R.,
and S. Murillo, "The WebSocket Protocol as a Transport for
the Binary Floor Control Protocol (BFCP)", draft-ietf-
bfcpbis-bfcp-websocket-05 (work in progress), October
2015.
[I-D.ietf-bfcpbis-rfc4582bis]
Camarillo, G., Drage, K., Kristensen, T., Ott, J., and C.
Eckel, "The Binary Floor Control Protocol (BFCP)", draft-
ietf-bfcpbis-rfc4582bis-15 (work in progress), October
2015.
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[I-D.pd-dispatch-msrp-websocket]
Dunkley, P., Llewellyn, G., Pascual, V., Roman, A., and G.
Salgueiro, "The WebSocket Protocol as a Transport for the
Message Session Relay Protocol (MSRP)", draft-pd-dispatch-
msrp-websocket-09 (work in progress), July 2015.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616,
DOI 10.17487/RFC2616, June 1999,
<http://www.rfc-editor.org/info/rfc2616>.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818,
DOI 10.17487/RFC2818, May 2000,
<http://www.rfc-editor.org/info/rfc2818>.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261,
DOI 10.17487/RFC3261, June 2002,
<http://www.rfc-editor.org/info/rfc3261>.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, DOI 10.17487/RFC4566,
July 2006, <http://www.rfc-editor.org/info/rfc4566>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008,
<http://www.rfc-editor.org/info/rfc5246>.
[RFC6101] Freier, A., Karlton, P., and P. Kocher, "The Secure
Sockets Layer (SSL) Protocol Version 3.0", RFC 6101,
DOI 10.17487/RFC6101, August 2011,
<http://www.rfc-editor.org/info/rfc6101>.
[RFC7118] Baz Castillo, I., Millan Villegas, J., and V. Pascual,
"The WebSocket Protocol as a Transport for the Session
Initiation Protocol (SIP)", RFC 7118,
DOI 10.17487/RFC7118, January 2014,
<http://www.rfc-editor.org/info/rfc7118>.
[RFC7395] Stout, L., Ed., Moffitt, J., and E. Cestari, "An
Extensible Messaging and Presence Protocol (XMPP)
Subprotocol for WebSocket", RFC 7395,
DOI 10.17487/RFC7395, October 2014,
<http://www.rfc-editor.org/info/rfc7395>.
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[WS-API] W3C and I. Hickson, Ed., "The WebSocket API", May 2012.
Authors' Addresses
Ram Mohan Ravindranath
Cisco Systems, Inc.
Cessna Business Park,
Kadabeesanahalli Village, Varthur Hobli,
Sarjapur-Marathahalli Outer Ring Road
Bangalore, Karnataka 560103
India
Email: rmohanr@cisco.com
Gonzalo Salgueiro
Cisco Systems, Inc.
7200-12 Kit Creek Road
Research Triangle Park, NC 27709
US
Email: gsalguei@cisco.com
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