The purpose of the KeepAlive request is to ensure that the RTSP session, specified by the Session header, is not closed by the server due to the communication link having been idle for a period of time. Clients need to send this request if they have not sent any other requests during the time interval specified by the server in the Session header, as specified in [RFC2326] section 12.37. Clients that are receiving RTP packets over TCP do not need to send this request while the server is sending RTP packets.
The KeepAlive request is defined as the GET_PARAMETER request method (sent by the client to the server), as specified in [RFC2326] section 10.8, with the following additional constraints:
The GET_PARAMETER request method includes the Session header (as specified in [RFC2326] section 12.37).
The GET_PARAMETER request MUST NOT have a message body.
The server's response to the KeepAlive request SHOULD NOT have a message body.
The following example shows a KeepAlive request.
GET_PARAMETER rtsp://myserver.com/mycontent.wmv RTSP/1.0 User-Agent: WMPlayer/22.214.171.12433 guid/B64345F5-8C45-4818-8A1A-4775F0923FAC Accept-Charset: UTF-8, *;q=0.1 Accept-Language: en-US, *;q=0.1 Session: 13856065358275910855 CSeq: 10