r & d BREAKING DOWN TECH —PRESENT AND FUTURE
60 MA XIMUMPC JUNE 2006
T
he DLNA is a consortium of nearly 300
companies in the computer and consumer
electronics industries, including Microsoft,
Sony, HP, Nokia, Philips, Kenwood, Cisco,
Toshiba, and Samsung. As the DLNA sees it,
every piece of today’s home-entertainment
gear exists on one of three isolated islands:
PCs and the Internet, home-theater and hi-fi ,
and mobile devices ranging from MP3 play-
ers to cellphones. None of the products can
easily communicate across categories with
each other, and where communication is pos-
sible, the consumer is typically required to buy
and confi gure a fourth category of product: a
media bridge.
Think about how dumb that is. You don’t
need a black box between your DVD player
and your home-theater system; you just plug
the player into your A/V receiver or TV and it
works. Integrating PCs, MP3 players, digital
cameras, and the like into your home-theater
system? Not so easy. And sending media the
other direction is even more problematic. It
can be done with today’s technology, but you
need streaming boxes and docking devices
to bridge the islands—not to mention a whole
menagerie of remote controls. All too often,
these intermediary devices are designed by
companies with expertise in either A/V or net-
working, but rarely both.THE SAME, BUT DIFFERENT
What the DLNA proposes is a new type
of network that’s optimized not just for
zipping bits from one PC to another, like
a corporate LAN, but also to encompass
consumer electronics. The goal is tosimplify the distribution of digital media
throughout the home, as well as to render
it accessible from just about anywhere,
using any digital device. If your network
was entirely DLNA compliant and you had
a DLNA-compliant cellphone, for instance,
you’d be able to view digital photos stored
on your NAS box or watch videos record-
ed on your network-attached DVR from
anywhere you had cellular service.
One thing the DLNA proponents don’t
intend to do is reinvent the wheel. The meth-
odology for routing digital media and control
signals across the network as described in the
DLNA network spec is already ubiquitous in
the PC market: TCPIP over Ethernet or Wi-Fi.
What distinguishes DLNA-compliant devices
is that each is capable of interoperating with
the other over a network. A/V receivers can
stream digital music stored on any hard drive
on the network, for instance, and TVs can do
the same with video.
And because a DLNA-compliant network
uses the existing Universal Plug and Play
(UPnP) device-control protocol framework,
any device from any manufacturer that’s
added to the network will be capable of not
only automatically confi guring itself, but also
discovering the presence and capabilities of
other devices on the network and automati-
cally working with them.DLNA TOPOLOGY
From a topological perspective, most DLNA-
compliant networks will have a PC or an
advanced set-top box at their hub. This central
device will manage and distribute digitalcontent among two broad classes of products:
digital media servers (DMS) and digital media
players (DMP). Some devices will, of course,
be capable of both functions. Version 1.0 of
the DLNA Interoperability Guideline is focused
exclusively on networked entertainment
devices involving imaging, audio, and video.
The group plans to expand its specifi cation
to include home automation (lighting,
HVAC, video surveillance, and so on) and
telecommunications (the cellphone scenario
described above) in the future.
DMS devices will be capable of acquiring,
recording, and storing media to and from a
variety of sources on the network. They’ll also
be responsible for enforcing any digital rights-
management constraints that have been
placed on the media (more on that topic later).
Desktop and notebook PCs, advanced set-top
boxes, digital cameras and camcorders, NAS
boxes, and multimedia mobile phones are all
examples of potential DMS devices.
DMP devices, meanwhile, will enable the
end user to navigate and play digital media
stored on your network. Examples of DMP
devices include TV monitors, home-theater
systems, gaming consoles, digital media
adapters, and PDAs. The server will host the
media, but the player will control and ultimate-
ly render it, using the network as a conduit.
Here’s an example: You’re sitting in front
of your TV (a DMP) and you want to view a set
of digital photos stored on your PC (a DMS).
Using your TV remote as a controller and your
TV as a display, you send a request over the
network to your PC, browse the contents of its
hard drive, locate the collection of photos youWhite Paper: DLNA Home Networks
Getting PCs and consumer-
electronics devices to work
together can be a major pain.
Here’s how the Digital Living
Network Alliance (DLNA) plans
to integrate these technologies
once and for all
BY MICHAEL BROWNHOW IT WORKS DLNA connects disparate devices
ÑDLNA provides a common language that makes it easy for your PCs, cellphones, and portable media players to
communicate with your home theater and other consumer electronics gear.MOBILE
DEVICES
COMPUTERS
AND PERIPHERALS
CONSUMER
ELECTRONIC
DEVICES