S&T's ATCaster is an ATSC 3.0 ROUTE and Signaling server. The ROUTE (Real-time Object delivery over Unidirectional Transport) protocol is used to deliver content packaged in MPEG DASH Segments.
ATCaster generates the ATSC 3.0 low level signaling (LLS) on the well-known multicast address (188.8.131.52:4937).
ATCaster builds the Service Layer Signaling (SLS) and all related ROUTE sessions containing audio, video and Non-Realtime (NRT) data.
Usually ATCaster receives MPEG DASH segments pushed to it via WebDAV PUSH. Usually, this data is provided by a HEVC encoder, such as the ATEME TITAN Live, or possibly from a DASH Packager. ATCaster generates the appropriate UDP multicast outputs containing the ROUTE sessions and signaling.
For a broadcast scenario, these multicast transmissions are sent to an ATSC 3.0 Scheduler (such as the Enensys ATSCheduler).
In addition to ROUTE, ATSC 3.0 content can be MPEG Media Transport (MMT) based. MMT protocol (MMTP) is used to deliver Media Processing Units (MPU). MMT support will be added to ATCaster in Q3 2018.