Videoconferencing screen gems

Videoconferencing glossary

AES (Advanced Encryption Standard). A 128, 192- and 256-bit government encryption standard adopted by the National Institute of Standards and Technology in May 2002. It is orders of magnitude more secure against brute-force attacks than the much older DES.


Codec (coder/decoder). A device that converts video and audio signals from analog to digital and compresses them for transmission, reversing the process on the receiving end. All videoconferencing systems have one, typically in the hardware, but sometimes in the software and sometimes in both.


DES (Data Encryption Standard). A 56-bit encryption method adopted by NIST in 1972 for nonclassified government data. It is still in use, but has been eclipsed by the more secure AES.


H.264. A video compression standard, approved by the ITU in July 2003, that roughly doubled effective videoconferencing bandwidth, making conferencing over IP more feasible'and less risky to IT data infrastructure. It also allows serious videoconferencing to low-bandwidth networks.


H.320. The ITU standard for videoconferencing over circuit-switched networks such as ISDN.


H.323. The ITU standard that extended H.320 to packet-switched networks, such as Ethernet, Token Ring and the Internet.


MCU (Multipoint Control Unit). A device that connects multiple audio and video sites in simultaneous conferences. Also called a bridge.


Quality of Service. A variety of techniques for ensuring that network resources are available for optimal performance. One, DiffServ, defines Differentiated Services that help prioritize data packets coming across the network.

High quality, ease of use and security features propel videoconferencing systems

We don't have Dick Tracy watches and holographic Star Trek displays just yet, but videoconferencing is finally beginning to live up to its decades-old potential.

You can thank the Internet again, or, more precisely, the Internet Protocol behind it. In addition to data, IP networks, both private and public, are increasingly handling telephony traffic, as telecom carriers and IT departments seek cheap, worldwide access over now-ubiquitous broadband connections.

The early audio/video quality, reliability and setup problems have been pretty much ironed out, and an IP telephony revolution is carrying videoconferencing along with it.

Government agencies are getting the picture, employing new IP videoconferencing devices to remote offices and other far-flung places.

National Guard soldiers in Iraq saw family members open Christmas presents back home; President Bush and his national-security advisers in Washington conferred with generals in the region and commanders on the ground'the latter providing up-to-date assessments from suitcase conferencing systems right inside the war zone.

An advantage videoconferencing has is that it's one of the few IT categories largely driven by industry standards, in this case from the International Telecommunication Union. Two relatively recent ITU standards have spurred improvements in quality and ease of use, and made equipment more interoperable.

Emerging standards

ITU's H.323 standardized how multimedia is transmitted over packet-based networks such as Ethernet LANs and the Internet. The other key standard, H.264, doubled H.323 videocompression rates, relieving a previously risky burden on IT data networks. H.264 was ratified in July of last year and has been uniformly adopted in the current products from professional-class videoconferencing vendors.

This year, the key emerging standards are the Internet Engineering Task Force's Session Initiation Protocol, along with ITU's H.239 and H.350.

SIP, which prescribes how to initiate interactive communication sessions, could help make videoconferencing more widespread and easy to initiate, in large part because of an extension, called SIMPLE, that standardizes 'presence' awareness'that is, who is available for an audio or video conference on which kinds of devices.

H.239 standardizes dual data and video streams, which should make it easier to share data during Web conferences, according to industry observers. And H.350 unifies network directory services such as Active Directory and Lightweight Directory Access Protocol, making it easier to authenticate conference participants from a single universal directory.

The melding of videoconferencing into IP telephony is also making feasible a new generation of more personal devices, such as push-to-talk access, instant messaging video and desktop videophones.

'I really think video will magically appear on end users' desktops one day,' said Brian Riggs, principal analyst at Current Analysis Inc. of Sterling, Va. 'It's becoming much more of a point-and-click type of experience.'

Most professional videoconferencing still takes place over high-speed Integrated Services Digital Network lines or asynchronous transfer mode WANs, but analysts expect IP to take over in the next few years.

In a December report on video over IP, Gerald Kaufhold, principal analyst at In-Stat/MDR of Scottsdale, Ariz., wrote: 'We believe that during the next five years, Ethernet and Internet Protocol will be used to deliver digital video across the complete spectrum of applications, from high-end movie production, down to wireless multimedia video.'

It was only a year or three ago that IT managers couldn't dream their IP telephony dreams without living the nightmare of inadequate network bandwidth and quality of service issues. Vendors and analysts say aggressive upgrading by government agencies has nearly eliminated these worries.

'There are some agencies that have a network architecture that's video ready, and they don't even know it,' Nilssen jokes.

Professional videoconferencing hardware typically comes in several flavors. On the low end are PC-based desktop units, many of which have small speaker towers and camera platforms that plug into a USB port. Set-top units are essentially codecs with cameras built in that sit atop the video screen.

Integrated systems build in the display devices, sometimes in a sleek, space-saving flat-panel LCD, but more typically in meeting-room units on rolling carts or recessed into walls.

PC whiteboarding and document sharing is typically a data cable away, though VCON takes the approach of building a PC right into its conferencing units.

The accompanying chart includes personal and group videoconferencing hardware with sufficient quality of service and security to pass government muster, along with the endpoints'cameras, screens and microphones'you need for the complete package.

I've also included several codecs that don't have endpoints, but provide nice mix-and-match options for system integrators. They offer too much flexibility to be ignored.

David Essex is a freelance technology writer based in Antrim, N.H.

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