diff --git a/xep-0167.xml b/xep-0167.xml index adc6b136..c6a2e723 100644 --- a/xep-0167.xml +++ b/xep-0167.xml @@ -471,10 +471,10 @@ delivery-method=inline; configuration=somebase16string;

The term "early media" refers to media that is exchanged before a responder has definitively accepted a session request generated by an initiator. Early media is typically used to send ringing tones and announcements, using either audio streams or Dual Tone Multi-Frequency (DTMF) events.

-

In Jingle, the exchange of early media is established through use of the "content-add" action. In order to match the usage specified in &rfc3959; and &rfc3960;, when adding a content definition for early media the value of the &CONTENT; element's 'disposition' attribute MUST be "early-session" for mapping to a SIP Content-Disposition header value of "early-session" (if necessary). This enables endpoints or intermediate gateways to apply the application server model described in RFC3960.

-

An entity that generates a content-add for early media SHOULD specify the same codecs for both session media and early media (however, it is possible that the entity generating early media does not generate session media, for example in the case of an intermediate gateway or application server; in this case the entity MUST use one of the codecs advertised by the initiator).

-

Upon receiving a content-add action specifying the use of early media, the initiator's client SHOULD acknowledge the content-add and then send a content-accept (or content-reject) to the sender. When the responder subsequently sends a session-accept action, the acceptance MUST NOT be construued to include the content definition whose disposition is "early-session".

-

In handling early media and deciding whether to generate local ringing or play early media received from the responder or an intermediate gateway, the initiator's client SHOULD proceed as follows:

+

In Jingle, the exchange of early media is established through use of the "content-add" action. In order to match the usage specified in &rfc3959; and &rfc3960;, when adding a content definition for early media the value of the &CONTENT; element's 'disposition' attribute MUST be "early-session" for mapping to a SIP Content-Disposition header value of "early-session" (if necessary). This enables endpoints or intermediate gateways to apply the application server model described in RFC 3960.

+

An entity that generates a content-add for early media SHOULD specify the same codecs for both session media and early media (however, it is possible that the entity that generates the early media does not generate the session media, for example in the case of an intermediate gateway or application server; in this case the entity MUST use one of the codecs advertised by the initiator).

+

Upon receiving a content-add action specifying the use of early media, the initiator's client SHOULD acknowledge the content-add, complete any required transpor negotiation, and then send a content-accept (or content-reject) to the sender. When the responder subsequently sends a session-accept action, the acceptance MUST NOT be construed to include the content definition whose disposition is "early-session".

+

In handling early media and deciding whether to generate local ringing or to play early media received from the responder or an intermediate gateway, the initiator's client SHOULD proceed as follows:

  1. If no ringing notification is received via a session-info event containing a <ringing/> condition, do not generate local ringing.
  2. If a ringing notification is received and no early media is received, generate local ringing.
    3. @@ -1067,6 +1067,8 @@ Romeo Gateway Juliet |<------------------------| | | ack | | |------------------------>| | + | [TRANSPORT SETUP] | | + |<----------------------->| | | content-accept | | |------------------------>| | | ack | | @@ -1138,7 +1140,8 @@ Romeo Gateway Juliet - @@ -1147,13 +1150,15 @@ Romeo Gateway Juliet ]]> -

    Romeo then acknowledges the content-add action and immediately also sends a content-accept.

    +

    Romeo then acknowledges the content-add action.

    ]]> +

    Because the gateway (on behalf of the responder) specified a transport method of Raw UDP for the early session data, the initiator then would send a Raw UDP candidate to the gateway, inform the gateway that it is trying to send media to the candidate provided by the gateway, etc. See XEP-0177 for details.

    +

    Eventually the initiator would send a content-accept to the gateway.

    -