Where Network Meets Cloud (Part 2)
by Leslie Ellis // April 11 2011
Last week, we looked for the intersection of “cloud” – 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 system 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 transmitting out 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 ambiance – a chilled room filled with racks of gear – but instead of processors, modulators and combiners, data centers hold servers, servers, and more servers. Some to 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 everything.
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.
(As opposed to headends, where 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.)
Which 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.
This column originally appeared in the Platforms section of Multichannel News.