Figures 5.3–5.6 depict typical architectures for linear IPTV.
Figure 5.3 shows a content aggregator preparing the content at single source S for terrestrial distribution of the content to multiple remote telcos. This example depicts the telcos acquiring the service from an aggregator/distributor, rather than performing that fairly complex function on their own since it can be fairly expensive to architect, develop, setup, and maintain. The operator must sign an agreement with each content provider; hundreds of agreements are therefore required to cover the available channels and VOD content. Aggregators provide
the content to the operator, typically over satellite delivery and do a lot of the signal normalization and CA work. However, an additional per-channel agreement with one or more content aggregators is also needed.
Figure 5.4 is an architecture that is basically similar to that of Fig. 5.3, but the distribution to the remote telcos is done via a satellite broadcast technology. Satellite delivery is typical of how cable TV operators today receive their signals from various media content producers (e.g., ABC/Disney, CNN, UPN, Discovery, and A&E). In the case of the cable TV/Multiple Systems Operator (MSOs), the operator would typically have (multiple) satellite antenna(s) accessing multiple transponders on a satellite or on multiple satellites, and then combine these signals for distribution. See Fig. 5.5 for a pictorial example. In contrast, in the architecture of Fig. 5.6, the operator will need only one receiver antenna, because the signal
aggregation (CA, middleware administration, etc.) is done at the central point of content aggregation.
Zooming in a bit, the technology elements (subsystems) involved in linear IPTV include the following:
- content aggregation,
- uniform transcoding,
- CA management,
- encapsulation,
- long-haul distribution,
- local distribution,
- middleware,
- STBs,
- catcher (for VOD services).
Each of these technologies/subcomponents has its own specific design requirements, architectures, and considerations. Furthermore, these systems have to interoperate for an end-to-end complete solution that has a high QoE for the user, is easy to manage, and is reliable.
In turn, each of these subsystems can be viewed as a vendor-provided platform. Different vendors have different product solutions to support these subsystems; generally, no one vendor has a true end-to-end solution. Hence, each of the following can be seen as a subsystem platform in its own right:
- content aggregation,
- uniform transcoding,
- CA management,
- encapsulation,
- long-haul distribution,
- local distribution,
- middleware,
- STBs,
- catcher (for VOD services).