In SIP, what does the term "media stream" refer to?

In SIP, the term "media stream" specifically refers to the audio and video content exchanged during a session. This includes the actual media data that is transmitted between endpoints, such as voice conversations or video feeds, as part of a communication session established by SIP (Session Initiation Protocol).

Media streams are essential because they provide the content that users actually experience when communicating, differentiating them from the signaling information used to set up and manage the session. The signaling path—a function of SIP—is responsible for establishing the session and facilitating the connection, but it does not carry the actual user media. Software and connections mentioned in other choices refer to support structures around SIP but do not pertain directly to what a media stream is. Thus, the audio and video exchanged during the session is the core element that defines a media stream in the context of SIP communications.