Tip-Toeing into the Woolly Language of VoIP
by Leslie Ellis // April 29 2002
When people start to get indignant about the way their competitors characterize a technology – especially one of mutual interest — it usually means one side is onto something, and the other side isn’t at all happy about it.
Such is the case with voice over IP, or “VOIP.” Last week, a friend who writes about the telephone industry called, sounding vaguely indignant. How can cable possibly call its early VOIP work VOIP, he asked, when the IP portion of it stops at the headend, and doesn’t yet go all the way to homes?
That’s not voice over IP, he harumphed. Cable should call it “IP transport with circuit switching.”
Now that’s catchy.
Cable’s pursuit of telephone service as an advanced addition to its IP (Internet Protocol) passageway seems more a question of “when” than “whether.” While AT&T and Cox are the most active with phone service today (albeit not yet over the IP path), the buzz level among technologists up and down the MSO roster is amplifying.
And, as techno-buzz amplifies, so seep new words to trip over — usually at the precise moment you think you know what’s going on.
The gibberish list for telephone technology is so dense, and so lengthy, it can make even the most tolerant jargon-watchers shudder. It’s no surprise, really. The telephone industry is twice as old as the cable industry. That’s 50 more years to concoct and re-concoct acronyms and code words.
Just in case you’ve not yet run into the dizzyingly dull lexicon of the telephone world, here’s a tiny sampling, and translation, of what’s ahead: Soft switches. Line-controlled signaling (LCS). GR-303. Media terminal adapters (MTAs).
Like so many other instances, the language of telephony and VOIP technology describes new ways of doing pretty much the same old things. The whole notion of “packet-styled” voice service, and the telephony aspects of the CableLabs PacketCable project, for example, is to deconstruct the functions of a telephone switch into software. That way, MSOs can exchange phone traffic from their customers without ever having to get on or off the public switched telephone network, or PSTN.
This matters — to the wallet. The regional Bell companies (or whatever we call them now) make great piles of money at the entrance and exit points of their networks – a fact that, at one time, at least partly explained AT&T Corp.’s interest in buying Tele-Communications Inc. and MediaOne, which also had local networks, capable of passing phone traffic, but without the steep entry and exit fees.
But back to this week’s translatables.
A soft switch does in software what traditionally takes a few million dollars worth of hardware to do: Connect one person’s phone line to another person’s phone line, so they can talk to each other.
At its core, a soft switch is a server, like so many other things in the digital world. Calling it a “class 5 capable” soft switch means it replicates, in software, the features noted in the front pages of the phone book – making calls, or getting call waiting, call forwarding and caller ID. (A class 4 soft switch, on the other hand, replicates in software the stuff that happens between switches, which in the existing world are called “tandem” switches.)
Line controlled signaling, or “LCS,” is more cable-specific, in that it helps those operators who already spent gobs of money on class-5 switches to segue into IP-delivered phone, without stranding the original investment. An active discussion amongst participants in the PacketCable project at CableLabs, LCS uses a telephone protocol, or set of rules, known as “GR-303,” to map the digital packets comprising a phone conversation into the big expensive switch.
A multimedia terminal adaptor, or “MTA,” is the thing the goes in the house. Picture a cable modem with RJ-11 phone jacks on the back. Phone calls move in and out of an MTA over the DOCSIS (Data Over Cable Service Interface Specification) signal path.
Because it can handle both broadband Internet and telephony, the MTA is one of those ideas financial analysts like: Two revenue-producing services, one box. And, because the MTA builds on DOCSIS – which trimmed cable modem prices from the $700 range, in the mid-1990s, to the sub-$100 range now – it’s likely to be gentler on the budget than, say, a digital set-top.
This is just a tiny, tiny fraction of the language that will accompany cable’s foray into voice over IP over the next few years. As plans evolve, so will the methods to describe them.
With any luck, cable’s VOIP advance can be done without resorting to the six and seven letter acronyms common to telephony sector. We could, for example, make an acronym of my telco writer friend’s accurate, if strangely indignant, depiction of cable’s VOIP work so far: IPTWCS.
But let’s not.
This column originally appeared in the Broadband Week section of Multichannel News.
How A Film Becomes a VOD
by Leslie Ellis // April 15 2002
It’s sometimes easy to overlook the origins of a movie, when contemplating the myriad steps that make it a VOD attraction for digital video customers.
Yet the transit of a film, in today’s digital world, introduces language that can glaze pretty quickly – usually within a sentence or two. And then there you are, a participant in a conversation that just beelined out of your knowledge precinct. Let it go a few sentences further, and you’re nodding awkwardly while wondering how rude it would be to ask for a quick rewind and explanation.
Here’s a sampling of the new lingo describing a movie’s journey to a VOD server: Digital asset. Digital package. And, one of my personal favorites (it sounds so wise), meta data. Baseball euphemisms are here, too: Pitcher. Catcher.
And now, for the frame-crunching tale of a movie’s 44,000+ mile voyage to VODville.
Did I mention? You’re going along.
Say you’re the guy in Fantastic Voyage who shrinks — but instead of coursing through human arteries, you belt a few bars of Thomas Dolby’s “She Blinded Me with Science,” which transforms you into a digital bit. Your mission is to ride shotgun from the studio to the headend.
First, you and the film are loaded into an unmarked van and couriered to a post-production facility. There, for a fee expressed in dollars-per-minute, you get compressed, encoded into an MPEG-2 file, and imprinted onto digital linear tape (DLT) – you’re now “in the can (baby).”
On the squashed side of the compressor, you’re now part of a 3 or so Gigabyte file. You and the audio goes with you, and some overhead for other stuff, are coded for MPEG-2 transportation, at a rate of 3.75 Megabits per second (Mbps). You’re still naked, in terms of encryption.
It is here that you and your digital bit brethren, as constituents of the digitized, compressed and encoded film, become known as a “digital asset.” You matter. You become part of a film database that holds you and information about who wrote you, directed you, produced you, and acted in you.
You, the digital asset, get transferred to a satellite uplink – maybe by courier, maybe more directly, depending on your owner’s set-up.
But before being jettisoned into the zone of geo-synchronous orbit, three more digital assets need to be slipped in with you. One is the cover artwork that depicts you. Another is the promotional trailer.
The third is the meta data.
“Meta,” in a broad sense, means transcendent. In an applied sense, “meta data” is data that describes other data. It’s the information that would otherwise be on the sticker of the tape container for the film, in pre-digital times: Title. Run time. Actors. Writers. Rating. Summary. Availability dates. Expiration dates.
Meta data gets tucked into your overall transmission vessel as an XML (extensible markup language) file, so that certain portions of it can be manipulated a la the Internet.
The meta data, trailer, cover art, and movie get wrapped together, and are now known as a “digital package.”
Here’s where the baseball begins. In the parlance of N2Broadband, a company making the things that create, manage and move “digital assets,” your next step is to get “pitched” up to the satellite. The pitcher is a server located at the uplink. You are the ball: A digital package comprised of digital assets. You get encrypted, so that nobody pirates you along the way.
You can likely guess what happens after you hurtle 22,300 miles to the satellite, then down again to a headend satellite receiver. You get caught, by a “catcher” – another N2Broadband term. It, too, is a server, but more in the sense of a short-term cache. Its job is to recognize you, prep you for who needs you, descramble you, and squirt you to the VOD server. If this sounds like a stutter-step, remember that you’re but one movie among hundreds, with potential zillions of on-demand TV programs right behind you. Being disorganized about who gets what, when, is a sure recipe for digital mayhem.
All along the way, you’re checked and double-checked to make sure you’re ok – an Internet backchannel usually exists between the uplink and the receive site, so that any missed packets can be re-requested. (Alas, if you’re the missing packet, you’re probably in the same cosmic pile as that sock you inexplicably lost en route from the hamper to the washing machine.)
That’s the lingo of the journey, just in case you inadvertently glaze over during a cocktail buzz phrase attack about that “robust, scalable, digital asset and metadata management system for the broadband space.” They just mean they’ve come up with something that keeps a movie safe with its baggage during its trip to become a VOD event.
This column originally appeared in the Broadband Week section of Multichannel News.