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Optimizing the Network for Multiscreen Video Delivery
February 01, 2012 | By Juniper
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Transcript
WHITE PAPER

Optimizing the Network for Multiscreen Video Delivery
Enabling a Profitable Long-Term Content Delivery Strategy

Table of Contents
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Background. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
A Vision for Operator Converged Content Delivery. . . . . . . . . . . . . . . 5
Converged Content Delivery Implementation and Use Cases. . . . . . . . . . . . . . 7
OTT Content Caching: Unmanaged Content to Unmanaged Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
VOD Content to the Multiple Screen Clients. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Optimizing VOD Content Delivery to Secondary Screens: Adaptive Streaming. . . . . . . . . . . . . . 10
Adaptive Streaming Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Adaptive Stream Publishing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Linear TV Programming to Secondary Screens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Using the CCDN to Enable Linear TV Programming NPVR Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Putting it All Together. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
New Service and Revenue Opportunity . . . . . . . . . . . . . . 16
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Appendix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Abbreviations and Acronyms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
About Juniper Networks . . . . . . . 17
Table of Figures
Figure 1: Network content caches distributed throughout an operator’s network. . . . . . . . . . . . . . . . . . . . . . 4
Figure 2: Converged content delivery networks must deliver any content to any device, using a variety of
protocols and client formats.. . . . . . . . . . 5
Figure 3: Multi-tier, hierarchical caching infrastructure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 4: Converged content delivery network, delivering all types of content to any device. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 5: Popular OTT content can generate significant amounts of traffic on the network.. . . . . . . . . . . . . 8
Figure 6: Bandwidth savings in a transparent caching demonstration. . . . . . . . . . . . . . . . . . . . . 8
Figure 7: Basic call flow for OTT Internet content . . . . . . . . . . . . . . . 9
Figure 8: Converged content delivery for VOD to primary screen clients (STB/TV). . . . . . . 10
Figure 9: Adaptive stream publishing process. . . . . . . . . . . . . . 11
Figure 10: Converged content delivery enables the extension of premium VOD content to multiple devices. . . . . 11
Figure 11: Converged content delivery network supports content delivery and session control protocols
for VOD to multiple screen clients. . . . . . . . . . . . . . . 12
Figure 12: Extending linear TV programming to multiscreen devices. . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 13: NPVR capabilities for linear TV to multiscreen devices. . . . . . . . . . . . . . . 14
Figure 14: Converged content delivery can enable NPVR capability to the primary screen. . . . . . . . . . . 14
Figure 15: Content and network awareness enables the most efficient distribution and delivery of content.
Content can be pre-positioned and/or dynamically fetched based on user requests. . . . . . . 15
Copyright ⓒ 2011, Juniper Networks, Inc. 3
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
Introduction
Consumers today are presented with an increasingly diverse selection of content offerings. The increasing popularity and
availability of online video content—much of it coming from “over-the-top” (OTT) sources—gives subscribers more choice
than ever before as to how they are entertained. In addition to the growing amount of content itself, users are also able to
access this content on a wider variety of devices both inside and outside the home.
For cable operators, these shifting viewing habits can be seen alternately as a challenge or as an opportunity, depending on perspective. On the one hand, OTT content consumes a tremendous amount of bandwidth on MS O networks—adding costs while adding little or no incremental revenue. In many ways, this content is also directly competitive with the television and VOD offerings cable providers already offer to their subscribers.
However, on the other hand, broadband access is a very profitable business for the cable industry. Keeping customers happy by providing them quality access to all the content they desire is not only good business but could also very well be a regulatory requirement in the near future.
At the same time, the ability to capitalize on this shifting consumer behavior is also critically important for the industry.
Cable providers need to be able to monetize the delivery of time-shifted and place-shifted video content—with new revenue streams generated through some combination of subscribers, services, or advertising.
The effect on network operators can be summarized by the need to pursue two parallel efforts—cost-optimizing the network for efficient delivery of OTT content while at the same time deploying the infrastructure that enables incremental growth through a new generation of services. While these goals would at first glance appear to be at odds with one another, in reality they can both be achieved with a new generation of content delivery technology—referred to henceforth as the converged content delivery architecture.
A converged content delivery architecture can both optimize the network for online video delivery (reducing costs), while
at the same time provide the foundation for innovative new entertainment services for premium content delivery. The
foundation of this converged content delivery architecture begins with next-generation content caching platforms, which can
be deployed at multiple points across the operator network, in a hierarchical, multi-tier design.
Today, these caches provide storage and streaming capabilities primarily for OTT-based content, where content is populated
via a Web server origin fetch mechanism (or cache miss) in response to user requests. However, it’s easy to see how this
same user-initiated dynamic content request-miss-fetch-cache process can be applicable—and beneficial—for VOD content
distribution and delivery (which today is largely populated through the network via operator pre-positioning). Extending this
foundation of distributed storage and streaming resources to VOD delivery can improve network efficiency, and it can also
facilitate the delivery of VOD content to secondary screens—such as wireless tablets, mobile devices, and PC clients—via
support for HTTP protocols and associated client capabilities such as adaptive streaming support.
Likewise, the pre-positioning mechanisms today used for operator-owned VOD content could also be extended to third-party
web-based content. Pre-positioning select content would benefit both subscribers, who would experience improved quality,
and the Web content owners, who would likely be willing to pay for the privilege of having select content delivered from
within an operator’s network.
As operators extend their content offerings to secondary screens, this infrastructure of network content caches can also
have benefits for linear programming delivery—enabling the extension of linear TV to new subscriber devices via the same
capabilities mentioned previously. Additionally, the storage and caching capabilities on these platforms would enable new
capabilities for linear TV, such as network-based personal video recording (NPVR). Figure 1 illustrates how a converged content
delivery network would consist of distributed network-based content caches that can store and stream a range of managed
and unmanaged content, populated via a combination of pre-positioning and dynamic cache miss and fetch mechanisms.
4 Copyright ⓒ 2011, Juniper Networks, Inc.
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
Figure 1: Network content caches distributed throughout an operator’s network
By making these network content caches a fundamental component of the network engineering design, operators can
reduce the impact of OTT Internet content and also more efficiently deliver premium services such as multicast linear
programming and VOD unicast content. Long term, the content caching and delivery infrastructure can become tightly
integrated with the network itself, enabling dynamic service engineered paths that provide the best route between a user
and a requested piece of content based on parameters that factor in network topology and load as well as the location of
the content and user. Tying together the routing infrastructure and the content caching infrastructure in this manner is a key
principal of the converged content delivery network.
This paper outlines the vision for a converged content delivery network and the technologies that are making this possible.
Background
Historically, content delivery has been addressed by parallel, but mostly independent, initiatives. Cable operators have for
many years possessed content delivery infrastructures to deliver VOD and linear TV content to the primary screen (a set-top
box-connected TV). In recent years, this infrastructure has evolved to enable new services such as video on demand and
other enhanced TV services such as subscriber interactivity using their remote controls and STBs.
However, this infrastructure has remained largely focused on the delivery of premium content to the television set, not to
Internet-connected elements such as PCs or the new generation of tablets. Delivering premium content to these other
devices offers up a different set of challenges (and protocols) than delivering content to the television set. When delivering
content to a STB, the cable operator has control over the entirety of the delivery process—it is occurring over a fully managed
network. However, delivering content to other screens—even if they are within the home and connected via the operator’s
broadband connection—involves some degree of transport over an unmanaged network that the operator cannot control.
In the home, this is most often the consumer’s Wi-Fi connection, which could be supporting any number of devices sharing
the same bandwidth, or could have any number of connectivity challenges due to physical proximity, interference, etc.
Outside the home, as is the case with “TV Everywhere,” there is an even greater degree of unmanageability as the user now
could be using any type of network to access the content. This unmanageability means content must be delivered differently,
and technologies such as adaptive streaming (discussed in detail next) are increasingly important for operators who want to
deliver such services.
Delivery of content over the Internet using HTTP as the predominant session request and control protocol of the World Wide
Web (WWW) has been greatly assisted by content delivery network (CDN) service providers, such as Akamai and Limelight,
who play an important role in distributing and delivering content efficiently using network caching technologies. However,
these traditional CDN providers are designed to address the challenges of content delivery from the perspective of an online
Network
Content Cache
Tier 1
Network
Content Cache
Tier 1
Network
Content Cache
Tier 1
Internet
Content Origins
• Broadcast TV
• Cable TV
• Video on Demand
Content Repository
and Processing
INTERNET
OTT Content Miss/Fetch
VOD Content Pre-positioning
Linear TV
Subscriber
Multiscreen
Devices
• OTT Video
• User-generated video
• Streaming movie
services
• Internet TV services
Copyright ⓒ 2011, Juniper Networks, Inc. 5
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
media organization. From the perspective of a cable operator, these third-party CDNs do not directly address the costs of
Web and OTT content delivery, since CDNs still rely on the MS O’s edge and access network to distribute content. Of course,
CDNs operated as separate businesses also do not contribute toward helping the network operator monetize the delivery of
Web content.
More recently, the deployment of network content caching technology is emerging to help MS Os and network service
providers (NSPs) mitigate the effect this popular Internet content has on their networks. Transparent caching helps
broadband providers by caching popular content within their own networks—reducing the amount of transit traffic generated
by OTT content. Transparent edge caching differs from traditional Internet CDNs (though both depend on caching as a
fundamental component) in that it can be used to transparently cache popular content from virtually any content owner—
not just those content owners who pay for CDN services. Because transparent edge caching can cache any and all Internet
traffic (not just that of CDN customers), and can be deployed very close to the edge of the network, it can significantly reduce
transit traffic on the network, lowering costs.
While all three of these content delivery applications—pay-TV operators’ VOD CDNs; Internet CDNs; and NSP transparent
caching of broadband access traffic—have similar goals (the efficient delivery of content to end users) and rely on similar
technologies such as caching and streaming, to date they have remained largely separate. In part this was due to the way
that consumers viewed content—when there was a clear distinction between the type of content available on the TV and
the type of content available on Internet-connected devices, separate delivery infrastructure was completely logical and
efficient. However, today, as alluded to previously, the way consumers view content is converging—they now expect TV and
VOD content on their mobile devices and Internet content on their TVs.
If the goal is the delivery of any content to any device (as surely it is), it follows that a converged infrastructure is the most
efficient—and perhaps the only—way to achieve this goal. The technology that enables this transition is just emerging on the
market. As required of any successful evolution, the technology can be implemented in a pragmatic and phased fashion.
A Vision for Operator Converged Content Delivery
Consumer viewing habits are currently undergoing a shift as profound as any since the advent of television many decades
ago. There are really two distinct aspects to this shift in viewing habits—first is the proliferation of devices, and second is the
availability of content for those devices. Today’s mobile and wireless devices, for example, have advanced to the point where
viewing premium video content is now both practically possible and enjoyable. In tandem, the availability of content for these
devices is increasing at a similarly rapid pace. This proliferation of devices can be referred to as the advent of “multiscreen”
entertainment services—the delivery of premium content to televisions, tablets, PCs, mobile devices, and whatever else is on
the consumer electronics horizon.
Figure 2: Converged content delivery networks must deliver any content to any device, using a variety of
protocols and client formats.
Protocols
Formats
End Devices
• Apple
• Adobe
• Microsoſt
Online
Content
Video on
Demand
Live/
LinearTV
Converged
Content
Delivery
Network
LSCP RTSP
HTTP
6 Copyright ⓒ 2011, Juniper Networks, Inc.
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
The second major shift in viewing habits—which is closely related to the first—is the transition from the traditional passive,
“lean-back” linear TV programming experience to a more involved experience where the users expect to have control over
not just what they watch, but also when they watch it and to the point above which screen they watch it on. What this really
means is that traditional linear TV programming is rapidly evolving to more of a personalized video-on-demand experience,
where subscribers use a variety of means (DVR, on-demand programming) to customize their entertainment schedule.
For network operators, these shifts in viewing habits can present challenges but first and foremost should be seen as an
opportunity to capitalize and monetize the delivery of multiscreen content. A converged content delivery network can help
operators seize this opportunity by more efficiently delivering linear programming and on-demand content to a wide variety
of subscriber screens, enabling operators to capitalize on these fundamental shifts in consumer behavior.
The foundation of a converged content delivery network is a new generation of network content caching platforms. The three
types of content delivery infrastructures discussed in the previous section all rely on the fundamental premise that there are
benefits to storing and delivering content as close to the edge as possible. Delivering content from the edge means less traffic
across the network, fewer chances for network conditions to affect viewing experience, and in general a more efficient and costeffective
network. This is true for all types of content, regardless of the screen to which the content is being delivered.
One of the fundamental principals of an efficient caching and content delivery architecture is the notion of hierarchical
caching across the operator network. Because it’s not practical or possible to deliver all content that users could ever request
from the edge, a hierarchical content delivery infrastructure creates a series of content delivery tiers, each of which delivers
content based on its relative popularity. These tiers are meant to align with the content access pattern of users, which is
often represented by a graph similar to the one in Figure 3.
Essentially, in most environments there is a set of content—whether it’s VOD content or Internet content—that is popular
at any given time. While this content might only be a fraction of the total available content, it generates a disproportionate
amount of demand from users. This is the content that should be cached at the network edge.
Figure 3: Multi-tier, hierarchical caching infrastructure
• 20,000-100,000 Titles
• Library Store: 50-125 TB
10,000
8,000
6,000
4,000
2,000
0
• 40% Library, 13% Hit Rate
• Local Storage: 12.5-64 TB
• 20% Library,
80% Hit Rate
• Local Storage:
5-32 TB
Increasing On-Demand Content Viewership
NGCO
EDGE
Regional
HEADEND
NGDC/Origin
REPOSITORY
METRO CORE INTERNET
• Internet video
• User generated video
• Streaming movies
• Streaming TV
• Online broadcasts
OTT ORIGIN
NETWORK SERVICE PROVIDERS
Copyright ⓒ 2011, Juniper Networks, Inc. 7
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
In a hierarchical content delivery infrastructure, there would also be one or more middle tiers, designed to deliver content that
generates a slightly lower number of requests (illustrated in the graphic in orange). Compared to the edge tier, this mid-tier
would likely have more storage but would handle a lower total number of requests.
The least popular content—the familar “long tail” of content—could be stored in a more centralized repository, in highly
scalable storage systems. Requests that experienced a cache miss in the previous tier can be fetched from the central
repository location and potentially added to the network caches in a lower tier level.
It’s important to understand this notion of hierarchical caching is fundamental to the converged content delivery vision. While
the concept of hierarchical caching is not entirely new—in fact it is used by CDNs today—what is new is the notion of a single,
converged infrastructure that can support all types of content. Combining support for all content types in an efficient, multitier
content delivery infrastructure can have significant benefits. In the following sections, we provide more detail on how this
is accomplished.
Converged Content Delivery Implementation and Use Cases
Essential to the notion of converged content delivery is the idea that the delivery node can cache and deliver content in all
the encoding formats required by the population of subscriber clients and their respective session control protocols. This
means that it can cache and deliver Internet-based content from OTT sources (HTTP), as well as from managed content
sources, and it can deliver VOD and linear TV programming to both television sets (RTSP/LCSP) and to extended viewing
platforms such as mobile devices (HTTP). The following diagram illustrates the concept of a converged content delivery
network delivering multiple types of managed and unmanaged content to a variety of user devices.
Figure 4: Converged content delivery network, delivering all types of content to any device
In the following sections we walk through the details of how a converged content delivery network would support each of
these content sources and user requests, looking at how to minimize the impact of OTT and other Internet content while also
supporting a variety of premium content distribution and delivery use cases for VOD and linear programming services.
OTT Content Caching: Unmanaged Content to Unmanaged Devices
The delivery of Internet-originated rich media content such as online video over the cable network creates a number of
challenges for cable operators. Because online, time-shifted videos are essentially unicast sessions, each time a user
requests a video (or other piece of content), it creates additional incremental traffic on the network. For a popular piece of
content, this can lead to the same content being delivered multiple times (hundreds or even thousands), and if the content
originates outside of a network operator’s geographic area, it can create additional expenses. This can quickly add up to a
lot of bandwidth—bandwidth that has a cost in terms of network devices, bandwidth fees, and operational support. This is
illustrated in Figure 5.
OTT
Content Origins
Converged Content
Delivery Network
Content Repository
and Processing
INTERNET
Subscriber
Multiscreen
Devices
RTSP/LCSP
Video on Demand
Linear Programming
HTTP VOD and Linear
Content Cache
HTTP OTT
Content Cache
Operator Content
Distribution Network
• Broadcast TV
• Cable TV
• Video on Demand
• OTT Video
• User-generated video
• Streaming movie
services
• Internet TV services
8 Copyright ⓒ 2011, Juniper Networks, Inc.
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
Figure 5: Popular OTT content can generate significant amounts of traffic on the network.
Transparent caching can improve the efficiency of this process by caching and delivering popular pieces of content.
Subscriber requests can be served locally from the transparent cache, rather than traversing the network with each request,
thus providing significant reductions in bandwidth and dramatically improving network scale and efficiency.
Unlike traditional third-party CDNs, which only store content based on business agreements, transparent caching when
deployed by operators helps ensure which content can and should be cached locally to optimize the operator network traffic
patterns. By deploying caches strategically throughout their networks, operators can cache and deliver popular content close
to subscribers, thus reducing the amount of transit traffic across their networks.
The following graphic is taken from a real-world demonstration that shows the reduction of traffic on a typical edge
node. The chart in the upper right shows content being served from the cache (green bars), and the main chart shows the
corresponding reduction in traffic across the network backbone over time (as more content is deemed cacheable).
Figure 6: Bandwidth savings in a transparent caching demonstration
PC
TV
MOBILE
INTERNET
Cable Operator Network
Online Video Content
Transit bandwidth and costs
Subscriber experiences
Last Bandwidth In: 1.94 Gbps Last Bandwidth Out: 1.97 Gbps
Average Bandwidth In: 7.56 Gbps Average Bandwidth Out: 7.05 Gbps
O-net BW In O-net BW Out
Provider Edge Router
Data Throughput
30
20
10
0
13:10
Cache Throughput
Copyright ⓒ 2011, Juniper Networks, Inc. 9
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
Transparent caches are thus named due to the fact that they operate as a transparent part of the network infrastructure—
that is their presence does not impact the user (other than the improvement in latency) or the content origin. In the U.S.,
the Digital Millennium Copyright Act (DM CA) spells out the guidelines by which these caches must operate to comply with
content owners’ rights.
In practice, users requesting content from the Internet would have their requests directed to the content delivery platform,
where the cache would inspect the request and determine whether the object exists already in the cache—if so it can be
served directly. If not, on cache miss, the content delivery node requests the content from the origin and stores a copy locally
for subsequent requests. This call flow is illustrated in the following figure, with the converged content delivery network
consisting of one or more tiers of network content caches participating in the client session request/stream.
Figure 7: Basic call flow for OTT Internet content
In the previous example, the content is originating from OTT sources, so the converged content delivery network is serving as
a transparent cache, as outlined earlier. The cable operator has no obligation or ability to prioritize the traffic. However, any
quality-of-service functionality (such as adaptive streaming) offered by the content origin is preserved.
VOD Content to the Multiple Screen Clients
At the opposite end of the spectrum, a converged content delivery network can also enable the delivery of managed content
to managed devices—in other words, the traditional cable TV and VOD services delivered to the STB box. In this example, the
primary benefit is the extension of cable TV and VOD to the network edge with the dynamic content distribution capabilities
exemplified by HTTP client request for content (outlined previously). By adding dynamic cache miss and fetch mechanisms
to the VOD infrastructure, operators can leverage a common framework of a converged content delivery network. Popular
titles could be pre-filled to storage based on forecasted popularity prior to content release (such as theatrical release of firstrun
movie titles), as would occur in a standard VOD content distribution network. However, converged content delivery would
also enable the dynamic population of network caches with content (Figure 8) based on user session requests reflecting
content title popularity.
Client session requests
Content from cache
INTERNET
OTT
Content Origins
Converged Content
Delivery Network
Content Repository
and Processing
Subscriber
Multiscreen
Devices
RTSP/LCSP
Video on Demand
Linear Programming
HTTP VOD and Linear
Content Cache
HTTP OTT
Content Cache
Operator Content
Distribution Network
Cache miss requests
Content fill from Origin
• Broadcast TV
• Cable TV
• Video on Demand
• OTT Video
• User-generated video
• Streaming movie
services
• Internet TV services
10 Copyright ⓒ 2011, Juniper Networks, Inc.
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
Figure 8: Converged content delivery for VOD to primary screen clients (STB/TV)
By using session request and content hit/miss mechanisms to dynamically ingest titles and populate storage for content
streaming from a tiered content distribution network (represented as the converged content delivery network in these
figures), operators can more readily adapt to shifting customer demand. A title that experiences a sudden gain in popularity,
for example, could be dynamically added to edge content caches without operator intervention. This could free up valuable
capacity on the network, reducing operating costs. Additionally, it’s this same mechanism that can lay the foundation for the
delivery of traditional VOD content to new devices.
Optimizing VOD Content Delivery to Secondary Screens: Adaptive Streaming
In addition to the traditional VOD model, where content is delivered to the STB, providers are increasingly looking to extend
the delivery of VOD and linear TV to multiple devices in the home. However, as discussed previously, delivering content to
new devices—even in the home—means that at some point the content is delivered over an unmanaged network where
bandwidth is not guaranteed for premium service delivery. This means operators must modify the way content is delivered if
they want to ensure a quality user experience.
Adaptive Streaming Introduction
Adaptive streaming based on HTTP is increasingly becoming the session control and delivery mechanism of choice in
supporting these new subscriber services. Content prepared for adaptive delivery gets encoded at multiple bit rates—usually
ranging from 100 Kbps to over 3 Mbps for HD video—and the client can shift between different bit rates of the same video
dynamically. This means that as bandwidth conditions fluctuate, the viewer experiences a continuous viewing experience
with only a (usually imperceptible) shift in viewing quality.
Adaptive streaming is an important tool for delivering content over unmanaged networks. However, it has a unique set of
delivery requirements. Individual players (for example, Apple, Microsoft, and Adobe) use different adaptive stream formats,
so delivery to multiple devices usually requires publishing content in specific formats per device—typically this requires
specialized servers. Also, a cable operator requires the delivery engine that is capable of serving content in adaptive streams.
Adaptive Stream Publishing
A converged content delivery network would eliminate many of the challenges of delivering adaptive content by
consolidating much of the adaptive stream publishing processes. The converged content delivery network in this instance
can ingest content encoded in H.264 or other efficient formats and prepare the content for HTTP adaptive delivery in
multiple content formats. This publishing process could occur at any point throughout the content delivery network—from
the head-end to the more distributed caching tiers.
Client session requests
Content from cache
INTERNET
OTT
Content Origins
Converged Content
Delivery Network
Content Repository
and Processing
Subscriber
Multiscreen
Devices
RTSP/LCSP
Video on Demand
Linear Programming
HTTP VOD and Linear
Content Cache
HTTP OTT
Content Cache
Content miss requests
Content fill from origin
Content pre-fill from origin • Broadcast TV
• Cable TV
• Video on Demand
• OTT Video
• User-generated video
• Streaming movie
services
• Internet TV services
Copyright ⓒ 2011, Juniper Networks, Inc. 11
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
As part of the adaptive stream publication process, the converged content delivery network performs the key tasks of
re-containerization (putting the content in the correct format “wrapper” for delivery to client devices using Adobe, Apple,
or Microsoft), as well as segmentation (preparing and chunking the various bit-rate files necessary to enable adaptive
streaming). Another key task is the publishing and translation of the metadata information (content titles, etc.), which can
also be performed by the content delivery platform.
Figure 9: Adaptive stream publishing process
Adaptive streaming is applicable to delivering both VOD and linear programming to secondary screens. In the case of VOD,
popular content can be distributed based on either operator pre-fill or via a cache miss then fetch based on client requests.
In this manner, operators can ensure popular content is cached and delivered from the edge, and longer-tail content can be
fetched from the origin content libraries on cache miss.
Figure 10: Converged content delivery enables the extension of premium VOD content to multiple devices.
In this example, the VOD content (which would normally be encoded in MPEG2) is transcoded at the head-end and then
pushed down to the content delivery node, which can perform the rest of the publishing process for adaptive streaming
(segmentation, metadata publishing, etc.), as described previously.
When this scenario outlining VOD delivery to secondary screens is combined with the previous example on VOD delivery to
the primary screen, we see that the converged content delivery network is required to support both the delivery protocols
as well as the management, session, and client request protocols for both second screen clients (HTTP) as well as the
traditional STB protocols (RTSP/LCSP).
Converged Content
Delivery Network
Adaptive Stream
segmented
video files in
player formats
Content Repository
and Processing
Live and On
Demand
Sources
Media
Encoder
Subscriber
Multiscreen
Devices
RTSP/LCSP
Video on Demand
Linear Programming
HTTP VOD
and Linear
Content Cache
HTTP OTT
Content
Cache
Videos encoded
at multiple
bitrates
Adaptive
Stream
Publishing
1250 Kbps
750 Kbps
500 Kbps
H.264/TS or File
HTTP
• Adobe Flash
• Microsoſt
• Apple
• Adobe Flash
• Microsoſt
• Apple
Converged Content
Delivery Network
Subscriber
Multiscreen
Devices
RTSP/LCSP
Video on Demand
Linear Programming
HTTP VOD
and Linear
Content Cache
HTTP OTT
Content
Cache
Adaptive
Stream
Publishing
• Adobe Flash
• Microsoſt
• Apple
• Adobe Flash
• Microsoſt
• Apple
OTT
Content Origins
Content Repository
and Processing
Content pre-fill from origin
Content miss requests
Content fill from origin
Content from cache
(adaptive bitrate delivery)
Client session requests
H.254
/HTTP
INTERNET
• Broadcast TV
• Cable TV
• Video on Demand
• OTT Video
• User-generated video
• Streaming movie
services
• Internet TV services
12 Copyright ⓒ 2011, Juniper Networks, Inc.
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
Figure 11: Converged content delivery network supports content delivery and session control protocols for
VOD to multiple screen clients.
Note that in the previous diagram, the VOD content can be delivered to the delivery platform either by pre-positioning it (an
operator push model) or by dynamic population due to user requests (a pull model) as presented in the tiered caching model
outlined in Figure 3. It’s also noteworthy to point out that the existing client session management protocols such as RTSP
and LS CP can be preserved as part of the converged content distribution network.
Linear TV Programming to Secondary Screens
In addition to delivering VOD content, with the advent of HTTP cache deployment the converged content delivery network
is readily poised to support the delivery of linear TV programming to secondary screens such as Apple devices and PCs in
the home, as well as operator Internet portals such as would be part of a “TV Everywhere” initiative. Delivering linear TV
to secondary screen clients is expected to typically require content encoded in H.264, with client sessions managed and
content delivered over HTTP, and would require content prepared for adaptive bit-rate delivery, as described previously.
Traditional linear TV programming is expected to continue to be delivered as multicast streams to the primary screen STB
using MPEG-2 encoded content over MPEG TS, as illustrated in the following, facilitated by the routers that are part of the
converged content delivery network.
INTERNET
OTT
Content Origins
Converged Content
Delivery Network
Content Repository
and Processing
Subscriber
Multiscreen
Devices
RTSP/LCSP
Video on Demand
Linear Programming
HTTP VOD and Linear
Content Cache
HTTP OTT
Content Cache
Operator Content
Distribution Network
Media Flow
(MPEG-2, H.264)
Stream control
(RTSP)
HTTP GET
HTTP Progressive
download, adaptive
streaming
Content pre-positioned upon initial ingest.
Cache fill from higher level caches per sub-demand.
HTTP Cache Service Control
and Content Location Functions
VOD Session and
Resource Management
Content
Management System
HTTP GET/REDIRECT
RTSP Setup/Redirect
Service redirect and
content location
control interfaces
Content and stream
management interfaces
• Broadcast TV
• Cable TV
• Video on Demand
• OTT Video
• User-generated video
• Streaming movie
services
• Internet TV services
Copyright ⓒ 2011, Juniper Networks, Inc. 13
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
Figure 12: Extending linear TV programming to multiscreen devices
Delivering linear TV programming to multiscreen devices extends an operators’ value to customers, creating subscriber
loyalty and increasing “stickiness.” Additionally, using a single, converged infrastructure to deliver content to both the primary
and secondary screens has other significant benefits, in terms of enabling new capabilities for these service offerings.
Using the CCDN to Enable Linear TV Programming NPVR Services
Having distributed content caching and delivery platforms throughout the network can be a powerful building block that can
be used to enable new subscriber services. The previous examples showed the value of using cache storage for file-based
pre-positioned assets such as VOD. However, cache storage can also be used to meet the requirements of many other
services based on linear TV. Many types of new services and applications that enable customized viewing schedules—driven
either by the subscriber or the operator, or by time and program—require cache storage to temporarily store linear TV content
for viewing at a later date. For example, operator managed scheduled record/playout services such as time-shifted TV
(TSTV), as well as subscriber- controlled capabilities such as personal and shared network-based video recording, can all be
enabled using the geographically distributed cache storage systems provided by the converged content delivery network.
As a specific example, these caching platforms can be used “on demand” by subscribers to record linear TV programming via
subscriber-initiated requests. Commonly known as network personal video recording (NPVR), this example is illustrated in
the following section. In this example for second screen clients, subscribers initiate a session request to record content, which
is subsequently cached in the converged content delivery network per NPVR service authorization. Playout and management
of the recorded content are controlled by the subscriber in much the same way that a home DVR is used.
INTERNET
OTT
Content Origins
Converged Content
Delivery Network
Content Repository
and Processing
Subscriber
Multiscreen
Devices
4) Linear TV Unicast
3) Second Screen Client
session requests
RTSP/LCSP
Video on Demand
Linear Programming
HTTP VOD
and Linear
Content Cache
HTTP OTT
Content
Cache
Adaptive
Stream
Publishing
1) Linear TV IGMP
Multicast Join
2) Linear TV Multicast
H.264/MPEG TS
MPEG2/MPEG TS
H.264.HTTP
MPEG2/MPEG TS
• Broadcast TV
• Cable TV
• Video on Demand
• OTT Video
• User-generated video
• Streaming movie
services
• Internet TV services
14 Copyright ⓒ 2011, Juniper Networks, Inc.
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
Figure 13: NPVR capabilities for linear TV to multiscreen devices
These same fundamental mechanisms can also be extended to enable NPVR services to the primary screen, delivered today
over MPEG TS to traditional STBs or, in the future, over HTTP to next-generation web-enabled TVs or STBs. In Figure 14, the
VOD server component initiates an IGM P multicast ingest of linear TV programming content (2, 3) per subscriber request
or by schedule per operator policy, and then records the linear TV programming content to storage. The recorded linear TV
content could then be streamed and viewed per subscriber VOD session request (4).
Figure 14: Converged content delivery can enable NPVR capability to the primary screen
In this capacity, the converged content delivery networking caching can be leveraged for all the operator services described in
the use cases presented previously, ranging from OTT content as part of a transparent proxy cache application to VOD and
linear TV programming services to all subscriber screens. In essence, any content delivered to any device.
Putting it All Together
For subscribers, the use cases previously described can enable true “any content on any device” capability. Combining the
previous use cases, we see that subscribers could potentially request any type of linear or VOD TV content using either their
primary or secondary screen, and the request could be served from the converged content delivery network. Delivery could
occur over either HTTP or MPEG TS, depending on the operator and client. Again, in this model content is encoded in both
MEPG-2 for traditional STB deployment and H.264 for emerging secondary screens at the operator’s content processing
center, though potential future applications exist for transcoding across the converged content delivery network.
INTERNET
OTT
Content Origins
Converged Content
Delivery Network
Content Repository
and Processing
Subscriber
Multiscreen
Devices
4) Linear TV Unicast
1) Secondary Screen
client session requests
RTSP/LCSP
Video on Demand
Linear Programming
HTTP VOD
and Linear
Content Cache
HTTP OTT
Content
Cache
Adaptive
Stream
Publishing
2) Linear TV IGMP
Multicast Join
3) Linear TV Multicast
H.264/MPEG TS
H.264.HTTP
• Broadcast TV
• Cable TV
• Video on Demand
• OTT Video
• User-generated video
• Streaming movie
services
• Internet TV services
INTERNET
OTT
Content Origins
Converged Content
Delivery Network
Content Repository
and Processing
Subscriber
Multiscreen
Devices
1) Primary Screen STB
client session requests
4) Linear TV Unicast
MPEG2/MPEG TS
3) Linear TV Multicast
MPEG2/MPEG TS
RTSP/LCSP
Video on Demand
Linear Programming
HTTP VOD
and Linear
Content Cache
HTTP OTT
Content
Cache
Adaptive
Stream
Publishing
2) Linear TV IGMP
Multicast Join
MPEG2/MPEG TS
MPEG2/MPEG TS
• Broadcast TV
• Cable TV
• Video on Demand
• OTT Video
• User-generated video
• Streaming movie
services
• Internet TV services
Copyright ⓒ 2011, Juniper Networks, Inc. 15
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
While the previous discussion shows the workings and advantages of converged content distribution and delivery, to fully
recognize the advantages of converged content delivery network, we also need to consider what is occurring at the network
transport level. By combining what’s happening on the content delivery platforms with behavior at the network layer, we
can fully optimize the network for content delivery. The end goal for this is for the content delivery network to detect where
content is available, the current state of network resources, and the content request load for the various services being
offered. To achieve this, what is needed is a network-wide session and content management system that can intelligently
align content distribution, network resources, and user requests.
Content routing technologies provide the knowledge of where content resides, and Application-Layer Traffic Optimization
(ALTO; IETF RFC 5693) is emerging as a promising technology that can enable this tight alignment of networks and content.
Originally developed as a means by which to improve the efficiency of P2P applications, ALTO takes into account factors
such as network topology, route costs, and link utilization to help route requests to the most efficient source for a given piece
of content. IETF draft-penno-alto-cdn-02 outlines the extension of ALTO principles for use in content delivery networks.
In essence, user requests for any type of content would be handled by a session and resource management (SRM) system,
capable of determining the request for any content—RTSP or HTTP. This SRM would interact with an ALTO server and a
content router, which has information about where content is located within the network, based on periodic advertisements
from content delivery platforms (similar to BGP route advertisements). The integration of the ALTO service’s network
topology information with content routing means that content serving requests can now take into account a range of
network and content-based factors—including the relative location of the user and the content, the available network and
content server resources, route cost analysis, and content popularity (Figure 15).
Figure 15: Content and network awareness enables the most efficient distribution and delivery of content.
Content can be pre-positioned and/or dynamically fetched based on user requests.
This integration of network resources and the content distribution enables significant improvements in efficiency, enabling
operators to dynamically optimize resources in response to consumer demand. Additionally, this converged content delivery
network makes it simpler for operators to introduce many new and revenue-generating services.
Subscriber
Session and Resource
Management
Content Router
Client Request
ALTO Service
Content Management
OTT
Content Origins
Content Repository
and Processing
INTERNET
Service Management
Converged
Content Delivery
Platform
Converged
Content Delivery
Platform
Converged
Content Delivery
Platform
Topology Information
Content
Information
Content
Information
Content Served
Ingest
Fetch
Fetch
• Broadcast TV
• Cable TV
• Video on Demand
• OTT Video
• User-generated video
• Streaming movie
services
• Internet TV services
16 Copyright ⓒ 2011, Juniper Networks, Inc.
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
New Service and Revenue Opportunity
With a converged content delivery network, operators can more efficiently and cost-effectively deliver content to the primary
and secondary screens. This extension of content to new screens can provide many opportunities for revenue generation,
as well as improvements in subscriber services. For example, there is the immediate opportunity for expanding operator ad
revenue enablement associated with delivery across multiple screens. When subscribers transition from primary STB screen
viewing to the secondary screens they are essentially transitioning from a multicast to unicast delivery, and with that comes
the opportunity to transition from brand to addressable (subscriber-targeted) advertising. Having the ability to leverage
both types of advertising is an exciting advantage for operators to offer through their ad sales divisions, well up and beyond
traditional spot ad insertion models they primarily offer today.
Additionally, with control of the content delivery network and the traditional IP network could develop compelling offerings
that can be extended to online content providers. Services that enable online content providers to distribute content to the
operators’ subscriber base with improved quality of experience could be very valuable.
In short, having a consolidated platform that supports both the traditional primary screen and secondary screen content
delivery provides operators with a single point of manageable and revenue generation that is key in their ability to enable new
services, grow new ad revenue sources, and manage costs and increase future ROI.
Summary
Shifting user viewing habits are forcing a change in the way content is delivered, and cable operators are at the forefront
of this evolution. A converged network can give operators the technology required to lead the industry with an innovative
converged approach to content delivery that combines all aspects of content delivery—including all combinations of
managed and unmanaged devices and content—in a single, converged solution. Implementing a converged content delivery
network can help operators meet the dual objectives of cost reduction and incremental revenue, and it can be the foundation
for future profitability.
Copyright ⓒ 2011, Juniper Networks, Inc. 17
WHITE PAPER - Optimizing the Network for Multiscreen Video Delivery
2000396-001-EN Mar 2011 Printed on recycled paper
Copyright 2011 Juniper Networks, Inc. All rights reserved. Juniper Networks, the Juniper Networks logo, Junos,
NetScreen, and ScreenOS are registered trademarks of Juniper Networks, Inc. in the United States and other
countries. All other trademarks, service marks, registered marks, or registered service marks are the property of
their respective owners. Juniper Networks assumes no responsibility for any inaccuracies in this document. Juniper
Networks reserves the right to change, modify, transfer, or otherwise revise this publication without notice.
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Appendix
Abbreviations and Acronyms
ALTO Application-Layer Traffic Optimization
BGP Border Gateway Protocol
CDN Content Delivery Network
CCDN Converged Content Delivery Network
DM CA D igital Millennium Copyright Act
DVR D igital Video Recorder
HD High Definition
HTTP Hypertext Transfer Protocol
IETF Internet Engineering Task Force
IGM P Internet Group Management Protocol
LS CP L ightweight Stream Control Protocol
MPEG M oving Picture Experts Group
MS O M ultiple Services Operator
NPVR Network-based personal video recording
NSP Network service provider
OTT Over-the-top
P2P Point-to-point
RFC Request for Comments
RTSP Real-Time Streaming Protocol
SRM S ession and resource management
STB S et-top box
TSTP Time-shifted TV
VOD Video on Demand
WWW World Wide Web
About Juniper Networks
Juniper Networks is in the business of network innovation. From devices to data centers, from consumers to cloud providers,
Juniper Networks delivers the software, silicon and systems that transform the experience and economics of networking.
The company serves customers and partners worldwide. Additional information can be found at www.juniper.net.
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