| Abstract: | This specification defines a Jingle transport method that results in sending data via the In-Band Bytestreams (IBB) protocol defined in XEP-0047. Essentially this transport method reuses XEP-0047 semantics for sending the data and defines native Jingle methods for starting and ending an IBB session. |
| Author: | Peter Saint-Andre |
| Copyright: | © 1999 - 2010 XMPP Standards Foundation. SEE LEGAL NOTICES. |
| Status: | Experimental |
| Type: | Standards Track |
| Version: | 0.3 |
| Last Updated: | 2010-02-16 |
WARNING: This Standards-Track document is Experimental. Publication as an XMPP Extension Protocol does not imply approval of this proposal by the XMPP Standards Foundation. Implementation of the protocol described herein is encouraged in exploratory implementations, but production systems are advised to carefully consider whether it is appropriate to deploy implementations of this protocol before it advances to a status of Draft.
1. Introduction
2. Protocol
3. Adding a Session to a Bytestream
4. Processing Rules and Usage Guidelines
5. Determining Support
6. Security Considerations
6.1. Encryption of Media
6.2. Use of Base64
7. IANA Considerations
8. XMPP Registrar Considerations
8.1. Protocol Namespaces
8.2. Protocol Versioning
8.3. Jingle Transport Methods
9. XML Schema
Appendices
A: Document Information
B: Author Information
C: Legal Notices
D: Relation to XMPP
E: Discussion Venue
F: Requirements Conformance
G: Notes
H: Revision History
Jingle [1] defines a framework for negotiating and managing data sessions over XMPP. In order to provide a flexible framework, the base Jingle specification defines neither data transport methods nor application formats, leaving that up to separate specifications. The current document defines a transport method for establishing and managing data exchanges between XMPP entities using the existing In-Band Bytestreams (IBB) protocol specified in In-Band Bytestreams [2]. This "jingle-ibb" method results in a streaming transport method suitable for use in Jingle application types where packet loss cannot be tolerated (e.g., file transfer); however, because the "jingle-ibb" transport method sends data over the XMPP channel itself (albeit not the Jingle signalling channel), it is intended as a transport of last resort when other streaming transports cannot be negotiated.
The approach taken in this specification is to use the existing IBB mechanisms described in XEP-0047 for transporting the data, and to define Jingle-specific methods only to start and end the in-band bytestream.
Initiator Responder | | | session-initiate | | (with IBB info) | |--------------------------->| | ack | |<---------------------------| | session-accept | |<---------------------------| | ack | |--------------------------->| | IBB "SESSION" | |<==========================>| | session-terminate | |<---------------------------| | ack | |--------------------------->| | |
This flow is illustrated in the following examples (to prevent confusion these use a "stub" description instead of a real application type).
First the initiator sends a Jingle session-initiate request.
Example 1. Initiator sends session-initiate (stub)
<iq from='romeo@montague.lit/orchard'
id='xn28s7gk'
to='juliet@capulet.lit/balcony'
type='set'>
<jingle xmlns='urn:xmpp:jingle:1'>
action='session-initiate'
initiator='romeo@montague.lit/orchard'
sid='a73sjjvkla37jfea'>
<content creator='initiator' name='stub'>
<description xmlns='urn:xmpp:jingle:apps:stub:0'/>
<transport xmlns='urn:xmpp:jingle:transports:ibb:0'
block-size='4096'
sid='ch3d9s71'/>
</content>
</jingle>
</iq>
The responder immediately acknowledges receipt (but does not yet accept the session).
Example 2. Responder acknowledges session-initiate
<iq from='juliet@capulet.lit/balcony'
id='xn28s7gk'
to='romeo@montague.lit/orchard'
type='result'/>
If the offer is acceptable, the responder returns a Jingle session-accept. If the responder wishes to use a smaller block-size, the responder can specify that in the session-accept by returning a different value for the 'block-size' attribute.
Example 3. Responder definitively accepts the session
<iq from='juliet@capulet.lit/balcony'
id='bsa91h56'
to='romeo@montague.lit/orchard'
type='set'>
<jingle xmlns='urn:xmpp:jingle:1'
action='session-accept'
initiator='romeo@montague.lit/orchard'
responder='juliet@capulet.lit/balcony'
sid='a73sjjvkla37jfea'>
<content creator='initiator' name='stub'>
<description xmlns='urn:xmpp:jingle:apps:stub:0'/>
<transport xmlns='urn:xmpp:jingle:transports:ibb:0'
block-size='2048'
sid='ch3d9s71'/>
</content>
</jingle>
</iq>
The initiator then acknowledges the session-accept.
Example 4. Initiator acknowledges session-accept
<iq from='romeo@montague.lit/orchard'
id='bsa91h56'
to='juliet@capulet.lit/balcony'
type='result'/>
The foregoing Jingle negotiation replaces the <open/> element from XEP-0047. Therefore the initiator can now immediately begin sending IBB packets using an IQ-set for each chunk as described in XEP-0047, where the responder will acknowledge each IQ-set in accordance with RFC 3920 [3].
<iq from='romeo@montague.net/orchard'
id='ls72b58f'
to='juliet@capulet.com/balcony'
type='set'>
<data xmlns='http://jabber.org/protocol/ibb' seq='0' sid='ch3d9s71'>
qANQR1DBwU4DX7jmYZnncmUQB/9KuKBddzQH+tZ1ZywKK0yHKnq57kWq+RFtQdCJ
WpdWpR0uQsuJe7+vh3NWn59/gTc5MDlX8dS9p0ovStmNcyLhxVgmqS8ZKhsblVeu
IpQ0JgavABqibJolc3BKrVtVV1igKiX/N7Pi8RtY1K18toaMDhdEfhBRzO/XB0+P
AQhYlRjNacGcslkhXqNjK5Va4tuOAPy2n1Q8UUrHbUd0g+xJ9Bm0G0LZXyvCWyKH
kuNEHFQiLuCY6Iv0myq6iX6tjuHehZlFSh80b5BVV9tNLwNR5Eqz1klxMhoghJOA
</data>
</iq>
<iq from='juliet@capulet.com/balcony'
id='ls72b58f'
to='romeo@montague.net/orchard'
type='result'/>
Once the parties have finished using the bytestream (e.g., because a complete file has been sent), either party can send a Jingle session-terminate action.
Example 7. Initiator terminates the session
<iq from='romeo@montague.lit/orchard'
id='hz81vf48'
to='juliet@capulet.lit/balcony'
type='set'>
<jingle xmlns='urn:xmpp:jingle:1'
action='session-terminate'
initiator='romeo@montague.lit/orchard'
sid='a73sjjvkla37jfea'>
<reason><success/></reason>
</jingle>
</iq>
The other party then acknowledges the session-terminate and the Jingle session is finished.
Example 8. Responder acknowledges session-terminate
<iq from='juliet@capulet.lit/balcony'
id='hz81vf48'
to='romeo@montague.lit/orchard'
type='result'/>
As IBB is defined in XEP-0047, there is one session per bytestream (which can be used in both directions). To extend this idea, it might be useful to run multiple sessions over a single bytestream. This can be done by sending a transport-info message that authorizes an additional session, as shown in the following example.
Example 9. Initiator adds a session
<iq from='romeo@montague.lit/orchard'
id='znb376s4'
to='juliet@capulet.lit/balcony'
type='set'>
<jingle xmlns='urn:xmpp:jingle:1'>
action='transport-info'
initiator='romeo@montague.lit/orchard'
sid='a73sjjvkla37jfea'>
<content creator='initiator' name='stub'>
<transport xmlns='urn:xmpp:jingle:transports:ibb:0'
block-size='4096'
sid='bt8a71h6'/>
</content>
</jingle>
</iq>
Here the Jingle Session ID is the same ("a73sjjvkla37jfea") but the new IBB Session ID ("bt8a71h6") is different from the old IBB Session ID that is already in use ("ch3d9s71").
The same processing rules and usage guidelines defined in XEP-0047 apply to the Jingle IBB Transport Method.
To advertise its support for the Jingle In-Band Bytestreams Transport Method, when replying to Service Discovery [4] information requests an entity MUST return URNs for any version of this protocol that the entity supports -- e.g., "urn:xmpp:jingle:transports:ibb:0" for this version (see Namespace Versioning regarding the possibility of incrementing the version number).
Example 10. Service discovery information request
<iq from='romeo@montague.lit/orchard'
id='uw72g176'
to='juliet@capulet.lit/balcony'
type='get'>
<query xmlns='http://jabber.org/protocol/disco#info'/>
</iq>
Example 11. Service discovery information response
<iq from='juliet@capulet.lit/balcony'
id='uw72g176'
to='romeo@montague.lit/orchard'
type='result'>
<query xmlns='http://jabber.org/protocol/disco#info'>
<feature var='urn:xmpp:jingle:1'/>
<feature var='urn:xmpp:jingle:transports:ibb:1'/>
</query>
</iq>
In order for an application to determine whether an entity supports this protocol, where possible it SHOULD use the dynamic, presence-based profile of service discovery defined in Entity Capabilities [5]. However, if an application has not received entity capabilities information from an entity, it SHOULD use explicit service discovery instead.
A Jingle implementation SHOULD support security preconditions that are enforced before application media is allowed to flow over the bytestream, such as those described in Jingle XTLS [6].
See XEP-0047 for security considerations related to the user of Base64.
This document requires no interaction with the Internet Assigned Numbers Authority (IANA) [7].
This specification defines the following XML namespace:
Upon advancement of this specification from a status of Experimental to a status of Draft, the XMPP Registrar [8] shall add the foregoing namespace to the registry located at <http://xmpp.org/registrar/namespaces.html>, as described in Section 4 of XMPP Registrar Function [9].
If the protocol defined in this specification undergoes a revision that is not fully backwards-compatible with an older version, the XMPP Registrar shall increment the protocol version number found at the end of the XML namespaces defined herein, as described in Section 4 of XEP-0053.
The XMPP Registrar shall add to its registry of Jingle transport methods a definition for the "jingle-ibb" transport method. The registry submission is as follows:
<transport>
<name>ibb</name>
<desc>A method for data exchange over In-Band Bytestreams.</desc>
<type>streaming</type>
<doc>XEP-0261</doc>
</transport>
<?xml version='1.0' encoding='UTF-8'?>
<xs:schema
xmlns:xs='http://www.w3.org/2001/XMLSchema'
targetNamespace='urn:xmpp:jingle:transports:ibb:0'
xmlns='urn:xmpp:jingle:transports:ibb:0'
elementFormDefault='qualified'>
<xs:element name='transport'>
<xs:complexType>
<xs:simpleContent>
<xs:extension base='empty'>
<xs:attribute name='block-size' type='xs:short' use='required'/>
<xs:attribute name='sid' type='xs:string' use='required'/>
<xs:attribute name='stanza' use='optional' default='iq'>
<xs:simpleType>
<xs:restriction base='xs:NCName'>
<xs:enumeration value='iq'/>
<xs:enumeration value='message'/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
</xs:element>
<xs:simpleType name='empty'>
<xs:restriction base='xs:string'>
<xs:enumeration value=''/>
</xs:restriction>
</xs:simpleType>
</xs:schema>
Series: XEP
Number: 0261
Publisher: XMPP Standards Foundation
Status:
Experimental
Type:
Standards Track
Version: 0.3
Last Updated: 2010-02-16
Approving Body: XMPP Council
Dependencies: XMPP Core, XEP-0047
Supersedes: None
Superseded By: None
Short Name: jingle-ibb
Source Control:
HTML
RSS
This document in other formats:
XML
PDF
Email:
stpeter@jabber.org
JabberID:
stpeter@jabber.org
URI:
https://stpeter.im/
The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 3920) and XMPP IM (RFC 3921) specifications contributed by the XMPP Standards Foundation to the Internet Standards Process, which is managed by the Internet Engineering Task Force in accordance with RFC 2026. Any protocol defined in this document has been developed outside the Internet Standards Process and is to be understood as an extension to XMPP rather than as an evolution, development, or modification of XMPP itself.
There exists a special venue for discussion related to the technology described in this document: the <jingle@xmpp.org> mailing list.
The primary venue for discussion of XMPP Extension Protocols is the <standards@xmpp.org> discussion list.
Discussion on other xmpp.org discussion lists might also be appropriate; see <http://xmpp.org/about/discuss.shtml> for a complete list.
Errata can be sent to <editor@xmpp.org>.
The following requirements keywords as used in this document are to be interpreted as described in RFC 2119: "MUST", "SHALL", "REQUIRED"; "MUST NOT", "SHALL NOT"; "SHOULD", "RECOMMENDED"; "SHOULD NOT", "NOT RECOMMENDED"; "MAY", "OPTIONAL".
1. XEP-0166: Jingle <http://xmpp.org/extensions/xep-0166.html>.
2. XEP-0047: In-Band Bytestreams <http://xmpp.org/extensions/xep-0047.html>.
3. RFC 3920: Extensible Messaging and Presence Protocol (XMPP): Core <http://tools.ietf.org/html/rfc3920>.
4. XEP-0030: Service Discovery <http://xmpp.org/extensions/xep-0030.html>.
5. XEP-0115: Entity Capabilities <http://xmpp.org/extensions/xep-0115.html>.
6. Extensible Messaging and Presence Protocol (XMPP) End-to-End Encryption Using Transport Layer Security ("XTLS") <http://tools.ietf.org/html/draft-meyer-xmpp-e2e-encryption>.
7. The Internet Assigned Numbers Authority (IANA) is the central coordinator for the assignment of unique parameter values for Internet protocols, such as port numbers and URI schemes. For further information, see <http://www.iana.org/>.
8. The XMPP Registrar maintains a list of reserved protocol namespaces as well as registries of parameters used in the context of XMPP extension protocols approved by the XMPP Standards Foundation. For further information, see <http://xmpp.org/registrar/>.
9. XEP-0053: XMPP Registrar Function <http://xmpp.org/extensions/xep-0053.html>.
Note: Older versions of this specification might be available at http://xmpp.org/extensions/attic/
Added negotiation flow for block size; corrected some slight errors.
(psa)Minor changes to track modifications to XEP-0166; updated security considerations for consistency with other transport methods; added section on service discovery.
(psa)Initial published version.
(psa)END