Pureplay OTT Operators
These are completely distinct from the access networks and the application layer delivery. In reality the very large players such as YouTube and Netflix will work closely with connected TV and Set-Top Box vendors to provide native optimized applications closer to the broadcast OTT model, although there are many PC-based Set-Top Boxes on the market that can access Netflix and
YouTube APIs and display the content in their local browsers as if there was a native application. Pureplay OTT operators might not develop relationships with the broadcast network operators, leaving the content distribution to partner Pureplay CDNs. One thing they do share, and which defines them as Pureplay OTT operators, is that they do not have end-to-end QoS guarantees.
In that respect they are technically indistinguishable from traditional streaming services found online throughout the web today.
These models are all shown on the topology schematic of Figure 11.1.
I would like to highlight a few key things that I have tried to represent in this diagram.
The circle to the right shows the physical broadcast access networks that reach the end user. A subscriber who is connected to this wired physical network layer (which may well not be IP based) can connect through that physical layer to the cable TV broadcast signals. Consumers with IP access are able to reach the operator CDN, the IPTV services, and potentially third party Pureplay OTT services.
The circle in the middle outlines the broadcast operator's operational networks, where the content is prepared and distributed to the physical access networks.
The small circle shows a third party telecoms (or cable) network that provides the end user with Internet access through an ISP that is neither involved in the OTT services nor in the broadcast services.
Note that in the top-right corner the DTT and DTH broadcasters can use broadcast networks that are not physically connected to the end users. Broadcast models such as this provide no native return path, which is critical for IP-based OTT services. For DTT and DTH this means that a separate Internet connection must be provided to the end user, typically by ADSL or FTTH, and this may or may not be bundled with the OTT service subscription.
Within and between the right and the middle circles, operators can control QoS, and the perimeters of these circles show the boundaries where that control ends.
The circle to the left represents the Internet, where, for example, a Pureplay CDN might operate. The edges of that CDN network might offer public Internet peering (shown as the route) or private peering and transit connectivity (the — route), and this direct connection to the broadcast operator's physical IP network could provide a QoS managed environment from the CDN hand-off forward to the end user.
This topology does not allow for guaranteed end-to-end QoS, since the CDN only offers a best-effort SLA. In turn the Pureplay OTT provider can only pass on “improved” QoS to the broadcaster. The typical approach to the non-QoS regions between the CDN and the ISPs or operator networks is to provision significant extra capacity in interconnects and peering and cross their fingers - and to be honest, this model works very well.
Figure 11.1 Schematic of premium content delivery platforms.
That approach, however, is not usually viewed positively when commercial contracts are put in place. Therefore private links between the operator and the content provider are usually created for accountability reasons rather than technical ones. This can lead to certain OTT providers working closely with the broadcast operators, such as Netflix arranged with Comcast in the US.
This model is shown as the (—) line. It represents a service such as Netflix as an augmented service to IPTV generated inside Virgin Media and delivered over their network with QoS guaranteed end to end, or even simply to the traditional cable, DTT, or DTH service with little operational overhead for the broadcast operator, beyond charging Netflix for the regional operator CDN distribution as an incremental revenue to their core broadcast subscriptions.
In this model, end users may subscribe directly to Netflix as an extra expense on top of their basic broadcast package subscription.
Of course, free content such as YouTube or BBC iPlayer carries no premium subscription from the end users. In these circumstances the operator CDN costs may be perceived to be simply a loss leader for the OTT providers, so YouTube or BBC may simply opt to extend its web-facing streaming content to the Virgin Media Set-Top Box audience through the public Internet model. With this approach the user avoids becoming dependent on the operator CDN.
This tends to create a more level co-dependent playing field for both parties: the operator CDN might opt to internally bear the cost of bringing the content to the EPG, so that the Pureplay OTT services can be browsed. This can be as straightforward as supporting the OTT services in the Set-Top Box's browser.
The broadcast OTT provider would have to make an investment to do this, but the Pureplay OTT providers' content is a must-have that they cannot exclude from their package without losing subscribers.
In this case the cost of network transit between the Pureplay OTT providers'
CDN edge and the end user is free to the broadcast network if it is delivered by the Pureplay OTT operator and distributed through the end user's chosen ISP.
This is the lowest QoS SLA and accordingly the cheapest OTT model, but it is also usually good enough for most consumers.
At the other end of the spectrum, the (—) IP-encoded video can be delivered directly from the operator network to the broadcast access network and, so long as the end user is “on net" then QoS can be guaranteed. This would classify the IP delivered video as being IPTV; it is interesting to note that the same video delivered via a third party ISP would change the terminology from IPTV to OTT, and this QoS differential is often (questionably) cited as the wall that we have gone over when defining OTT, leading many to think that OTT is of worse quality than IPTV or broadcast.
Finally, point A shows a critical interface where the MHEG app, or similar EPG details that announce the existence of any OTT content over the traditional broadcast network, is established.
This thin line (seen by marker A in the head end) represents metadata and small application data that is distributed over the broadcast network to facilitate access to the broadcaster OTT content. It is exclusively available as part of those traditional broadcasts, and this couples these services to relationships between the broadcast network operators, the broadcast OTT operators, and the content providers. This closeness creates commercial control and is driving revenue for all these parties, something that Pureplay OTT services often do not do.
Arqiva, which delivers the Freeview Plus services in the UK, calls this version of broadcast OTT architecture “hybrid TV” with their particular product known as “Connect TV”
At an encoding and content preparation level, the only difference between OTT networks and typical web streaming workflows comes down to the encoding profiles for targeting the connected TVs and OTT Set-Top Box decoders.
At the network layer there are several models that vary cost, quality of service, and control of the paywall, and each provides different value to the various stakeholders.
To sum up, OTT has many topologies and workflows, but all share the common theme that the revenues they drive are typically, at least in part, earned by third parties external to the broadcast and ISP access networks used by the end users and subscribers.