ANSI SCTE 137-6-2017 pdf free download – Modular Headend Architecture Part 6: Edge QAM Video Stream Interface.
5 TECHNICAL OVERVIEW
The role of the EQAM in the video-on-demand and switched-digital-video architecture is to receive an IP unicast or multicast stream containing MPEG transport stream packets, and then produce that transport stream on one or more RF outputs for transmission over the hybrid fiber-coax cable plant.
5.1 Video EQAM Reference Architecture
5.1.1 Video EQAM Block Diagram X Figure 5–1 X shows a conceptual block diagram of a video EQAM. The EQAM has a management and control interface through which configuration messages, resource management traffic, and network management information pass. It also has one or more input interfaces upon which the IP-encapsulated MPEG transport streams arrive.
Those input interfaces feed input transport stream processing blocks that handle de-multiplexing the individual transport streams (based on UDP destination port number or IP multicast address information) from the input interface, providing de-jittering of those transport streams, and routing them to the appropriate QAM channel processing blocks. Each QAM Channel Processing block handles the generation of an output MPTS for a single QAM channel. It could be in passthrough mode, in which case it accepts a single MPEG Transport Stream from the input TS processing block, performs minimal processing, and forwards it to the QAM channel for modulation and transmission.
Alternatively, it could be in multiplexing mode, in which case it accepts a number of input transport streams (SPTS and/or MPTS), selects certain programs from those inputs, can perform program number remapping and PID remapping, generates PSI information, and multiplexes the selected programs into an output MPTS, which is then forwarded to the QAM channel for modulation and transmission.
Each physical RF Port on the output of the EQAM may produce multiple QAM channels (this example shows four), although that is not a required functionality in this specification.
The EQAM may be subdivided internally into multiple QAM Processing Blocks in which each input interface and output RF port is associated with a single QAM Processing Block. In this case, the input transport streams arriving at an input interface associated with one QAM Processing Block cannot be routed to RF Ports associated with a different QAM Processing Block.
This might be the case for an EQAM implemented as a series of linecards in a chassis that provides a single management and control interface. In the case where the EQAM can route any input transport stream to any QAM Channel, the EQAM could be considered to be implemented as a single QAM processing block.
This example shows three input interfaces and four RF Ports (each producing four QAM channels) per QAM Processing Block. This is simply meant as an illustrative example.
This block diagram is intended to provide insight into the functionality provided by the video EQAM; it is not intended to mandate a particular internal architecture or implementation.
5.1.2 Static vs.
Dynamic Sessions The term “session” in the context of an EQAM supporting VOD and SDV refers to the mapping of a single input transport stream (SPTS or MPTS), arriving encapsulated in UDP/IP, to a single output transport stream that is modulated on a particular QAM carrier.ANSI SCTE 137-6 pdf download.