RTCWeb JSEP XMPP/Jingle Mapping
draft-li-rtcweb-jsep-xmpp-mapping-00

Abstract

This document proposes mapping message representations between RTCWeb Javascript Session Establishment Protocol(JSEP) scheme and XMPP/Jingle [XEP-0166] messaging scheme. Such a signaling mapping is intended to enable Javascript to use XMPP/Jingle to establish a session between two RTCWeb enabled browsers.

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This Internet-Draft will expire on January 29, 2013.

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Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

• 1. Introduction
• 1.1. Terminology
• 2. Media Setup Overview
• 2.1. Initiating the Session
• 2.2. Exchange the ICE
• 2.2.1. Transport Information
• 2.3. Receiving the Session
• 2.3.1. Accept the Session
• 2.3.2. Terminate the Session
• 2.4. Updates to the Session
• 2.4.1. Add Media
• 2.4.2. Modify Media
• 2.4.3. Remove Media
• 2.4.4. Accept Media
• 2.4.5. Reject Media
• 2.4.6. Description Information
• 2.4.7. Result
• 2.4.8. Error
• 2.5. Other Actions
• 3. Example Message Flows
• 3.1. Exchange Candidates
• 3.2. Add Contents
• 3.3. Exchange Description Information
• 4. Security Considerations
• 5. IANA Considerations
• 6. Acknowledgements
• 7. References
• Author's Address

1. Introduction

In draft [I-D.ietf-rtcweb-jsep], it is mentioned that there are several options for the signalling mechanisms: ROAP, SIP or XMPP/Jingle.

This document focuses on XMPP/Jingle and tries to explain how to use JSEP and XMPP/Jingle to exchange session descriptions.

1.1. 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].

2. Media Setup Overview

The example here shows a typical call setup using the JSEP model. We assume the following architecture in this example, where UA is synonymous with "browser", and JS is synonymous with "web application".

In Figure 1, it shows the overall mapping architecture.

           
                        +----------------------+                      
                        |         Web          |         
                        |                      |
                        |       Server         |              
                        +----------------------+         
                          /                 \
                        /                     \      
            Jingle    /                         \   Jingle
                    /                             \
                  /                                 \
                /                                     \
        +-------------+                        +--------------+
        |     Web     |                        |      Web     |
        | Application |                        |  Application |
        + ----------- +                        + ------------ +
               ^                                       ^
               |  SDP                                  |  SDP
               |                                       |
               V (JSEP)                                V (JSEP)
        +-------------+                        +--------------+
        |   Caller    |                        |    Callee    |
        |             | <====== Media =======> |              |
        |   Browser   |                        |    Browser   |
        +-------------+                        +--------------+
            

Figure 1: JSEP-XMPP/Jingle Mapping Architecture

2.1. Initiating the Session

To initiate a session, the Caller can send the offer to the Callee by using Jingle "session-initiate" action.

CallerJS->CalleeJS: <jingle action="session-initiate"/> .

2.2. Exchange the ICE

2.2.1. Transport Information

To perform the ICE process, the Caller can exchange the ICE candidates with the Callee by using Jingle "transport-info" action.

CallerJS->CalleeJS: <jingle action="transport-info"/>.

CalleeJS->CallerJS: <jingle action="transport-info"/>.

2.3. Receiving the Session

2.3.1. Accept the Session

If the Callee accepts a session, it can send back the answer by using Jingle "session-accept" action.

CalleeJS->CallerJS: <jingle action="session-accept"/>.

2.3.2. Terminate the Session

To terminate a session, the Caller can send the offer to the Callee by using Jingle "session-terminate" action.

CallerJS->CalleeJS: <jingle action="session-terminate"/>.

2.4. Updates to the Session

2.4.1. Add Media

To add media (e.g.video) to an existing session, the Caller can use Jingle "content-add" action.

CallerJS->CalleeJS: <jingle action="content-add"/>.

2.4.2. Modify Media

To modify media (e.g.change audio to video) to an existing session, the Caller can use Jingle "content-modify" action.

CallerJS->CalleeJS: <jingle action="content-modify"/>.

2.4.3. Remove Media

To remove media (e.g.video) to an existing session, the Caller can use Jingle "content-remove" action.

CallerJS->CalleeJS: <jingle action="content-remove"/>.

2.4.4. Accept Media

If the Callee accepts the "content-add" action to an existing session from the Caller, Callee can send back answer by using Jingle "content-accept" action.

CalleeJS->CallerJS: <jingle action="content-accept"/>.

2.4.5. Reject Media

If the Callee rejects the "content-add" action to an existing session from the Caller, Callee can send back answer by using Jingle "content-reject" action.

CalleeJS->CallerJS: <jingle action="content-reject"/>.

2.4.6. Description Information

To send informational hints about parameters related to an existing session, for example, add new video sources to a call that already has video, the Caller can indicate that by using Jingle "description-info" action.

CallerJS->CalleeJS: <jingle action="description-info"/>.

2.4.7. Result

To acknowledge the description information to an existing session from the Caller, Callee can send back answer by using IQ stanza of "result" type. See [RFC6120].

CalleeJS->CallerJS: <iq type="result"/>.

2.4.8. Error

If there are errors occurred during an existing session, the Callee can send back answer by using IQ stanza of "error" type. See [RFC6120].

CalleeJS->CallerJS: <iq type="error"/>.

2.5. Other Actions

TBD 1: do we have usage for the following actions: "security-info", "session-info"?

TBD 2: do we need to redefine a transport method? If yes, we can use "transport-replace", "transport-accept", "transport-reject".

3. Example Message Flows

3.1. Exchange Candidates

In Figure 2, CallerJS uses Jingle "session-initiate" action to initiate a session with CalleeJS, and uses Jingle "transport-info" to exchange ICE candidates with CalleeJS. Then CalleeJS accepts the session using Jingle "session-accept" action. After the media session, CallerJS uses "session-terminate" action to terminate the session, and CalleeJS acknowledges with IQ stanza of "result" type.

 
             
    Caller JS                              Callee JS
       |                                       |                       
       |  <jingle action="session-initiate"/>  |                        
       |-------------------------------------->|       
       |                                       |
       |  <jingle action="transport-info"/>    |     
       |-------------------------------------->|
       |                                       |
       |  <jingle action="transport-info"/>    |     
       |<--------------------------------------|
       |                                       |
       |  <jingle action="session-accept"/>    |     
       |<--------------------------------------|               
       |                                       |
       |           Media Session               |     
       |<=====================================>|   
       |                                       |                       
       |  <jingle action="session-terminate"/> |                        
       |-------------------------------------->|           
       |                                       |                       
       |        <iq type="result"/>            |                        
       |<--------------------------------------| 
       |                                       |
              

Figure 2: Exchange Candidates

Message details go here...

3.2. Add Contents

In Figure 3, CallerJS uses Jingle "content-add" action to add video media to an existing session. CalleeJS accepts that by using Jingle "content-accept" action. For simplicity, candidate exchange is not shown.

 
             
    Caller JS                              Callee JS
       |                                       |                       
       |  <jingle action="content-add"/>       |                        
       |-------------------------------------->|   
       |                                       |
       |  <jingle action="content-accept"/>    |     
       |<--------------------------------------|
       |                                       |
       |           Media Session               |     
       |<=====================================>|   
       |                                       |
              

Figure 3: Add Contents

Message details go here...

3.3. Exchange Description Information

In Figure 4, CallerJS uses Jingle "description-info" action to add new video sources at the same time to a call that already has video. CalleeJS also uses Jingle "description-info" action to indicate the new sources to the remote side. After that, they uses IQ stanza of "result" type to acknowledge each other.

 
             
    Caller JS                              Callee JS
       |                                       |                       
       |  <jingle action="description-info"/>  |                        
       |-------------------------------------->|   
       |                                       |                       
       |  <jingle action="description-info"/>  |                        
       |<--------------------------------------| 
       |                                       |
       |          <iq type="result"/>          |     
       |-------------------------------------->|
       |                                       |
       |          <iq type="result"/>          |     
       |<--------------------------------------|
       |                                       |
       |           Media Session               |     
       |<=====================================>|   
       |                                       |
              

Figure 4: Exchange Description Information

Message details go here...

4. Security Considerations

TBD.

5. IANA Considerations

This document requires no actions from IANA.

6. Acknowledgements

The author would like to thank Kiran Kumar and Bert greevenbosch for the reviews and feedbacks.

7. References

Author's Address