RFC 5576  provides a mechanism to describe attributes of individual media sources (identified by their synchronization source) within a media stream. A mapping to Jingle as an extension to Jingle RTP Sessions (XEP-0167)  is defined in this document.
The SDP format defined in RFC 5576 is shown below.
This maps to Jingle as a <source/> element qualified by the 'urn:xmpp:jingle:apps:rtp:ssma:0' namespace. Since 'ssrc' is a media attribute in SDP, the <source/> element is included as child of the Jingle <description/> element.
Each ssrc-id maps to a <source/> element whose 'ssrc' attribute is set to the ssrc-id. The associated attributes map to <parameter/> children with 'name' and 'value' attributes. If there is no value in the SDP, the value parameter shall be omitted.
An example follows:
The SDP format defined in RFC 5576 is shown below.
This maps to Jingle as a <ssrc-group/> element qualified by the 'urn:xmpp:jingle:apps:rtp:ssma:0' namespace. Like the <source/> element, this is included as child of the Jingle <description/> element. The SDP 'semantics' parameter is mapped to the semantics attribute (for consistency with Jingle Grouping Framework (XEP-0338) ) and the list of ssrc-ids is mapped to <source/> elements whole 'ssrc' attribute is set to the ssrc-id.
A minimal example follows:
This is mapped to Jingle as follows:
If an entity supports source specific media attributes as described in RFC 5576, it MUST advertise that fact in its responses to Service Discovery (XEP-0030)  information ("disco#info") requests by returning a feature of 'urn:ietf:rfc:5576':
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 (XEP-0115) . However, if an application has not received entity capabilities information from an entity, it SHOULD use explicit service discovery instead.
This document introduces no additional security considerations above and beyond those defined in the documents on which it depends.
This document requires no interaction with the Internet Assigned Numbers Authority (IANA) .
This specification defines the following XML namespace:
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.
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remove obsolete mslabel and label lines.
Initial published version approved by the XMPP Council.