Where Network and Cloud Meet (Part 2)


— for it has lost its participle, it’s that popular —
and the network. Where does the network end
and the cloud begin? That is the question.

There’s no easy pocket map, but two signposts
exist. One is the swift rise of the “data
center.” Another lies in the tacit differences
between “server” and “service.”

Let’s start with the data center. For as
long as I can remember, the central nervous
system for any cable plant was (and is, for
now) the headend. It’s a term borrowed long ago from train
transit, to indicate a central point for signal collection, processing
and transmission to connected homes. (In rail transit,
the locomotive at the front, or “head” end, generates
the electricity needed for most everything else.)

These days, a place as important as the headend is the
data center. Same ambience — a chilled room filled with
racks of gear — but instead of processors, modulators
and combiners, data centers hold servers, servers and
more servers. Some ingest content coming in from content
delivery networks or CDNs — big, Internet-protocol backbones
moving content as fragments of files, not processed
streams of contiguous video packets.

Other servers store those video files; still others “transcode”
them, to suit the resolution and display needs of the screens at
the end of the line — TVs, sure, but also PCs, handhelds, tablets
and the growing landscape of video-capable gadgetry.

Still others work as “web-service” bridges between traditional
back-office functions and the new world of web-based

In a “cloud” sense, then, data centers are the place
where video content comes in over IP, gets wrapped in DRM
(digital rights management) and is sent out again in IP,
through the CMTS, to a cable modem, into a Wi-Fi or Ethernet
router in the house, to the display device.

(In a headend scenario, signals come in over satellite
or terrestrial antennas, get processed, encrypted, re-modulated,
combined, and sent out through headend controllers
to set-tops, connected to TVs.)

This brings us to the second video cloud differentiator
— the server vs. the service. In today’s “client-server” parlance,
a “client” — a set-top, let’s say — talks to a server
(think VOD pump). Each client knows precisely what data to
expect from that server, and if the server hiccups or nods
off, communication halts.

A “service” model extends traditional client-server activities
to a peer-to-peer model, where each client essentially
“discovers” the right server for what it needs. The servers
themselves, and their databases, might be “virtualized”
across multiple data centers. The data each client needs
may be assimilated from many different servers. One might
take the initial request (“I need video”), while others fulfill it.

Where does network meet cloud? In the data center,
for starters, using Web-service interfaces to the “classic”
(seems nicer than “legacy”) gear. One thing does seem certain:
Everywhere you look, “cloud” will continue to stretch a
hazy cover over everything we used to think we knew about
video transmission.

Stumped by gibberish? Visit Leslie Ellis at www.translation-please.com or multichannel.com/blog.