Just What Is A/V over IP?
A/V over IP Explained
How A/V and IP systems are merging to create one powerful network.
By Julie Knudson

Before A/V and IT systems started merging together into one overall network, organizations typically managed each system separately. Data signals were routed through IT’s servers and sent out to end users over Category 5 cables, video traffic was contained within its own platform and ran over coaxial cable and phone calls transited a private branch exchange (PBX) system before being carried to the desktop via an old school Category 3 cable. The systems were usually managed by different groups, with no crossover in equipment or expertise.

But today, those disparate systems are gradually coming together, and a single cabling backbone is often the launch pad for companies interested in converging their A/V and IP networks. “I think what we’re seeing now is that the A/V industry probably has a more structured cabling approach, which very much mirrors where folks who’ve been exclusively IT-, data-, or telephony-focused in the past have already gone,” says Derek Joncas, manager of Product Marketing at Extron Electronics in Anaheim, Calif.

An Architectural Merge

An increasingly wide range of systems are being merged into the traditional IT network architecture, including Voice over IP telephony solutions, videoconferencing platforms and presentation systems. And because conventional data cabling is ubiquitous in most modern buildings, a shared backbone is attractive to many organizations, who can often save money by using existing cables to distribute A/V signals throughout their facilities.

Misconceptions abound about what AV-IT convergence really is, says Ken Colson, vice president of Sales and Engineering at Tucker, Ga.-based LMI Systems, Inc. “A lot of people assume when you say A/V over IP, you’re simply running an audio/visual signal over a category cable, like Cat 5,” he says.

While that may indeed be the limit to convergence in some situations, other organizations have progressed to the implementation of more holistic network architectures, which often share switching equipment and other components in addition to backbone cabling. In those increasingly converged environments, the distribution of an A/V signal frequently occurs in a way that directly mirrors more conventional IP-only networks.

“A/V over IP is the ability to take analog or high-definition audio/visual signals and inject them into a network — either the existing IP network or it could be a closed network (meaning it’s separate from telephony or data traffic) — and distribute it to multiple endpoints,” Colson explains.

With the evolution of A/V and IT technologies, Joncas says the line between the two disciplines is blurring. “There’s not a big difference between how you manage a computer or server versus how you would manage an A/V appliance,” he says. Those similarities are leading more organizations to merge their previously standalone A/V systems into their overall IP network architecture. “IT administrators may be a little more comfortable with the idea that you can have many more A/V appliances on your network nowadays, and have some confidence that you’re going to be able to manage them,” Colson says.

Addressing Delays

As A/V traffic increasingly moves from just sharing cables within the IT network to actually moving through some of the same switches and other hardware components, one potential issue administrators must be ready to address is network latency (or a delay in processing network data).

“When you think of an A/V network nowadays, a lot of the information that’s being exchanged is very, very high speed data that has a very low latency requirement,” Joncas says. “If you pair that with a traditional IT network, that latency requirement doesn’t disappear.”

He says something as innocuous as users browsing the Web could inject increased latency into the network, but adds that most of today’s A/V devices include the processing capabilities needed to help manage and overcome the potential latency and quality of service concerns that may crop up when layering A/V signals over an IP network.

Scenarios where users are consuming content without any reference to when the content was generated may have a greater tolerance for network latency, Joncas explains, but “when you’re dealing with live signals, latency is the most important factor.” He cautions that careful design of the network’s architecture is paramount to managing quality of service issues.

Proactively addressing network latency and bandwidth issues could involve adding or upgrading equipment or services on the existing IT network, Colson explains. “One of the challenges you have with the need to distribute A/V signals is some resistance from IT directors as far as putting what they consider to be a bandwidth hog on their network,” he says.

Moving from a data-only environment to a mixed environment may also require that IT groups increase their knowledge of how A/V really works, Colson says, adding that basics such as “understanding how resolution needs — whether it be standard definition or high definition — equates to bandwidth requirements to push A/V through that network” are crucial to designing a network that can successfully support bandwidth-intensive, low-latency applications.

Colson says that organizations that rely on older networks may find it necessary to upgrade their switches to manage video priority, or even add switches or change to a virtual LAN to achieve the sort of traffic separation their particular case requires.

The convergence of A/V and IT infrastructures will look different in every enterprise. Each organization must carefully evaluate its needs, the level of funds they can devote to either developing a single robust architecture or multiple standalone systems, and the expertise available to them to manage a wide range of components within a holistic network or to instead oversee the provisioning of each platform individually. Where those needs and resources come together will ultimately dictate where the various systems share resources and where they remain disparate. TD End Icon Final 14 px



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