2.1 Transport
As defined by the Miracast v1.1 protocol [WF-DTS1.1], this extension uses RTSP, which uses TCP at the transport layer to maintain an end-to-end connection. The capability negotiation portion of this extension occurs over RTSP.
A new RTSP parameter is defined that is part of M3 capabilities request that will query for the sink’s support of hardware cursor and capabilities. If supported, the source will send mouse pointer position and shape updates to the sink over UDP, and the sink MUST decide which UDP port to use.
There will not be any acknowledgment scheme to ensure delivery of the mouse point position or shape changes, but because mouse pointer image packets are bigger and missing one greatly affects the user experience, the source sends the update multiple times to ensure the sink receives the update.
The source will expand all monochrome cursors into masked color cursors before sending to the sink.