ANSI SCTE 137-7 pdf free download

ANSI SCTE 137-7 pdf free download.Modular Headend Architecture Part 7: EQAM A rchitectural Overview Technical Report.
In the video architecture, digital video that is not broadcast continuously to service groups is controlled by the interaction of a service-specific client application on the STB, signaling to service-specific session managers to request receipt of a video stream. When the STB client requests a stream of the session manager, the session manager must acquire the necessary resources that allow the stream to be transported from source to destination. In order to acquire the necessary RF/QAM bandwidth and the Edge QAM device resources to transport the stream to the service group, the session manager requests an ERM component function to allocate the bandwidth to the session manager. The ERM component function may need to dynamically provision the Edge QAM device to prepare it to receive the stream and direct it to the appropriate RF output using the allocated MPEG Program Number. The components and interfaces in the video headend are described below.
The Session Manager functional component is used to establish a session with an STB client on which the client application can request video streams be directed to the STB and control the behavior of the stream. The session manager is responsible for collaborating with other components in the headend to acquire the necessary resources to insure the video stream can be delivered to the service group.
The ERM functional component is used to manage the use of transport bandwidth into the Edge QAM device and HFC bandwidth out the Edge QAM device. The Session manager uses the ERM to find an Edge QAM device with an RF output having sufficient bandwidth and connectivity to the STB service group (serving area). The ERM may have to provision some resources on the Edge QAM device to prepare it to receive the input stream and forward it out the appropriate RF port.
The Edge QAM device, or EQAM for short, has one or more ingress interfaces (typically gigabit Ethernet) and multiple RF QAM outputs. The EQAM accepts input MPEG SPTSs or MPTSs transported via UDP/IP (multicast or unicast) and multiplexes these input programs into an output MPTS that is then modulated and transmitted out one of the EQAM QAM RF outputs. An EQAM that is capable of performing these functions is known as a Video EQAM.
The STB receives the QAM channel by tuning to the proper frequency, and can decode a single MPEG program from the MPTS. The STB is also responsible for providing the decoded A/V stream to the subscriber output device (i.e., monitor or TV) for presentation.
The M-CMTS Core contains everything a traditional CMTS does, except for functions performed in the EQAM. The M-CMTS Core contains the MAC-Layer functionality and all the initialization and operational DOCSIS -related software. The MAC-I ayer functionality includes all signaling functions, downstream bandwidth scheduling, and DOCSIS framing. This diagram shows the Upstream Receivers for DOCSIS upstream channels located internally to the M-CMTS Core. However, there is nothing preventing an implementation of a Modular CMTS from using external upstream receivers. The DOCSIS Timing Interface (DTI) Server provides a common frequency of 10.24 MHz and a DOCSIS timestamp to other M-CMTS elements. DEPI, the Downstream External PHY Interface, is the interface between the M-CMTS Core and the EQAM. More specifically, it is an IP Tunnel between the downstream MAC in the M-CMTS Core and the downstream PHY in the EQAM. It contains both a data path for DOCSIS frames and a control path for setting up, maintaining, and tearing down sessions.ANSI SCTE 137-7 pdf download.