What is typically included in a "response" to a SIP message?

In a "response" to a SIP (Session Initiation Protocol) message, it is important to include a SIP status code indicating the success or failure of the request that was made. This status code is fundamental to the SIP signaling process, as it informs the sender about the outcome of their request. For example, if a call setup request is made, the response will include a status code that indicates whether the call was successfully established (e.g., "200 OK") or if there was an error (e.g., "404 Not Found").

The status code is crucial for the proper functioning of SIP communications, as it enables the sender to understand what action to take next based on the response received. Other facets such as media formats, active subscribers, or network traffic statistics might be relevant in different contexts but are not standard components of a SIP response message itself.