The Relationship Between Content Delivery and SDN/NFV: It’s About Mobility

Operators have recognized from the first that video probably represents their largest incremental opportunity.  There’s also been a lot of hype around the video market, particularly focusing on the notion that Internet OTT delivery of video would displace all other video forms.  Like most popular notions, this is almost completely unsupported and even illogical, but it’s covering the real issues and opportunities.  Let’s look at the truth instead.

Channelized material represents the great majority of video consumed today, and this material is delivered in what is often called “linear” or “linear RF” form, to a set-top box and to a TV through an HDMI cable or coax.  For material that is delivered on a fixed schedule this is a highly efficient model, and it’s my view that assertions that any company with either fiber to the home or CATV in place would abandon it are inaccurate.  Imagine the traffic generated by a million viewers of a popular TV show if all those views were IP-based.

Where IP is increasingly a factor is in delivery of video that is either off-schedule (on demand) or delivered to a mobile device or computer.  The popularity of mobile video has grown as people have become dependent on their smartphones and tuned to having entertainment access through them.  I think that the trend toward online delivery of traditional TV-on-demand reflects the fact that mobile use of video creates a platform with favorable exploitation costs—better than you could have in trying to build linear-RF solutions to TV on demand.

If mobile drives on-demand viewing trends, then it’s fair to ask how mobile changes video content delivery overall.  There are clearly “back-end” issues impacting content delivery networks (CDNs), but there are also viewing-habit changes that could have a profound impact on video overall.

Wireline content delivery is well understood.  The access network is an aggregation hierarchy, with consumer connections combined into central office trunks, and then further aggregated at the metro/regional level.  The goal for most CDNs was not to optimize this hierarchical structure, but to avoid the variable but generally significant performance variations that would arise were content to be streamed over Internet peering connections.  Instead, the CDN caches content close to the head-end point of an aggregation network.

With traditional CDNs, a user who clicks on a URL for video is redirected (via DNS) to a cache whose location is based on whatever quality of experience or infrastructure optimization strategies the network operator applies.  The content is then delivered from that point throughout the experience.  Cache points can be aggregated into a hierarchy too, with edge cache points refreshed by flow-through video and deeper ones filled in anticipation of need.

Mobile video changes this in two important ways.  First, the mobile user is mobile and so the optimum cache location is likely to change over time.  This is particularly important because mobile infrastructure has many aggregation points as towers aggregate into Evolved Packet Core elements and onward to gateways.  It’s also typically more expensive and more easily overconsumed than wireline.  Second, the mobile user is often highly socially driven in terms of consumption.  People don’t usually share their living rooms and view collectively, but almost every mobile user will be a part of an active social group (virtual or real) and the habits and behaviors of others in the group will impact what any member decides to view.

For both SDN and NFV, the dynamism inherent in mobile CDN operation presents an opportunity.  SDN could be a cheaper and faster way of defining transient paths between the cell sites supporting mobile users and their content cache points.  NFV could be used to spin up new cache points or even to build “video distributor” points that would repeat video streams to multiple users.  Some network operators have expressed interest in what could be called “scheduled on-demand” viewing, where a mobile user joins a community waiting for delivery of something at a specific time.  This would enable video delivery “forking” to be established.  Fast-forward, pause, or rewind would require special handling but operators say some market tests show users could accept a loss of these features for special pricing or special material (live streaming, for example).

Dynamic CDN is fine, but it’s the social-viewing changes that could have a profound impact.  Twitter is often used today to comment on TV shows, either among friends or in real time to the program source.  This model doesn’t require additional technical support, but with some new features the social integration of content could be enhanced.

Tweeting on scheduled TV relies on the schedule establishing an ad hoc community of users whose experience is synchronized by transmission.  Most useful enhanced social features/services would be associated with establishing simultaneous viewing for a community of interacting users (like the “forking” mentioned above) that would insure that they could all view the same thing at the same time.  Users could then interact with each other on the content-shared experience, and could invite others to join in the experience.

A variation on this social sharing would use metadata coding of the content.  Coding of scenes by an ID number or timestamp would allow a social user to refer to a scene and to synchronize others to that specific point.  It could also be used to jump from one video to another based on the coding—to find other scenes of a similar type, with the same actors/actresses, etc.  It would also be possible to rate scenes and find scenes based on the ratings of all users, of a demographic subset, or among a mobile user’s social contacts.

You can see that social video viewing/sharing would change the dynamic of content delivery.  Most obviously, you’d probably want to spawn a process to fork such sharing experiences from a common cache if the people were together, and perhaps even to make each viewer a parallel controller of the experience—one person pauses for all, for example.  You might also want to create multiple independent video pipes to a viewer if they’re browsing by metadata, and you’d need a database application to actually do the browsing.

As video content viewing becomes more social, it starts to look a bit like videoconferencing, and I think that over time these two applications would combine.  A videoconference might be a multi-stream cache source with each participant a “sink” for whichever streams they wanted to view.  They could then rewind, pause, etc.  And there are already many applications in healthcare (as a vertical) and compliance (as a horizontal) where metadata coding of conference content would be highly valuable.

Video of this sort could become a powerful driver for both SDN and NFV, but I don’t think it would be easy to make it a killer app, the app that pulls through a deployment.  Consumer video is incredibly price-sensitive, and operators will be pressed to make a business case for mass deployment in a market with low margins like that.  Still, if I were a mobile and video vendor (like Alcatel-Lucent) I might be taking a serious look at this opportunity.  At the least it would guarantee engagement with the media and consumer population.

I think the video opportunity for SDN and NFV shows something important at a high level, which is that NFV and SDN are not driven as much by “virtualization” as by dynamism.  A virtual router in a fixed place in a network for five years doesn’t need SDN or NFV, but if you have to spin up one and connect it for a brief mission, service automation efficiency is the difference between being profitable and not.  That’s an important point to remember, because most of our current network missions are static, and fears of thinking outside the “box” in the sense of physical-network constraints and missions could compromise both SDN and NFV’s long-term benefits.