Telepresence interoperability: Multistream standard needed

Telepresence interoperability among competing vendors remains elusive, thanks to a lack of standards governing multiscreen systems. But progress is chugging along.

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No one worries about which vendor manufactured a phone or what signaling standard the service provider uses before making a call, but the plug-and-play freedom of IP telephony continues to elude telepresence. The lack of standards for multiscreen systems has made telepresence interoperability little more than an aspiration among competing vendors, but recent activity in the market suggests that progress is chugging along.

"Back in the day, [video conferencing] was run by one or two companies, so standardization was straightforward … Everybody was focused on the H.323 standard," said John Bartlett, principal of NetForecast, an independent engineering and consulting firm. "New [vendors] are stepping into the market. They're not all sticking to the same standards … and true interoperability means that a bunch of standards need to be met."

Even if you have a standard, you need the commitment of vendors to ensure [that] the implementation of standards and protocols really do create a good end result.

David Hsieh
Vice President of Marketing for Emerging Technologies, Cisco Systems

However, there's a big barrier to telepresence interoperability today. No major technical standards body has ratified a way for equipment to negotiate multiple streams of audio and video inherent to immersive, multiscreen systems.

Polycom recently announced it would begin supporting Telepresence Interoperability Protocol (TIP), a Cisco Systems protocol that allows telepresence systems to negotiate sessions between endpoints and to multiplex multiple streams into a single stream. Polycom is the first vendor other than Cisco to announce formal support for it. 

"We're putting the technology olive branch out there," said John Antanaitis, vice president of product marketing at Polycom. "That's not completely altruistic -- let's not kid ourselves -- but we're doing it so people will trust Polycom to [support any deployment] … and we know no one is going to have a pure, single-vendor environment."

Cisco originally developed TIP as a proprietary protocol for its Cisco Telepresence products but released its specifications to the market last year as an open protocol; ownership was later transferred to the International Multimedia Telecommunications Consortium (IMTC), a nonprofit industry group that has created a working group around TIP and made access to its specifications license-free. TIP has not been submitted to any standards body for ratification, but the IMTC is conducting interoperability testing, according to Cisco.

"Even if you have a standard, you need the commitment of vendors to ensure [that] the implementation of standards and protocols really do create a good end result," said David Hsieh, vice president of marketing for emerging technologies at Cisco. "We believe if we help encourage interoperability for telepresence, it will make telepresence ubiquitous…. Our goal is not to fight over points of market share."

Logitech LifeSize has not seen strong demand from customers or partners for telepresence interoperability -- at least for immersive suites like Cisco's -- and has not yet invested in TIP interoperability, according to Michael Helmbrecht, vice president of product marketing at LifeSize.

Although he acknowledged that LifeSize may change its position, Helmbrecht said the specifications for TIP are too narrowly defined to ever gain support for standardization. Instead, LifeSize is looking to the IMTC and standards bodies for answers.

"TIP … is not so much a specification or standardization, in my opinion, as it is reference architecture for what Cisco built into their telepresence systems," Helmbrecht said. "You're not interoperating [with Cisco]. You're almost emulating [Cisco]."

Developing a standard for telepresence interoperability

Though still characterized as a "work in progress," a draft document from a working group in the Internet Engineering Task Force (IETF), co-authored by engineers from Cisco and Polycom, outlines the case for a standardized way for telepresence vendors to resolve the multistream issue. 

"Different telepresence systems … use disparate techniques, and they describe, control and signal media in dissimilar fashions," the group wrote in the draft. "This makes [interoperability] difficult at best and sometimes impossible."

IETF task force engineers wrote that "some degree of interworking is possible through transcoding and translation" but hastily noted that those are not the solutions. "This requires additional devices, which are expensive and not entirely automatic," they wrote.

The group is in the early stages of developing a potential telepresence standard that would clearly define how vendors should implement various specifications around "transmitting, selecting and rendering media streams," according to its charter.

The working name for the potential standard is Controlling Multiple Streams for Telepresence (CLUE), whose charter calls for a standard to be submitted to the Internet Engineering Steering Group (IESG), a branch of the IETF, at the end of this year.

A common foundation based on standards would put telepresence interoperability on a swifter path, versus vendors having to invest millions of dollars in research and development to backwards engineer their gear to support a competitor's architecture, according to Antanaitis.

"When standards are created and used, everybody has equal access to the standard, starts from the standard and builds up," he said. "Having to [adopt] what Cisco developed for themselves several years ago … is like [Cisco] saying, 'We'll all play together, but we'll always use my home court and my ball.'"

Standards alone don't equal telepresence interoperability

Jeffrey Levine is still early in his LifeSize high-definition (HD) video conferencing deployment and has yet to evaluate telepresence, but the director of IT at Power Home Remodeling Group said he expects vendors to provide interoperability as investment protection.

Levine chose LifeSize partly because of the ability of its products to interoperate with homegrown video conferencing bridge and Asterisk-based VoIP system, as well as his digital signage infrastructure. That signaled to him that LifeSize will likely meet his future needs, especially as he expects to double his deployment by the end of this year.

"I don’t [foresee] any issues with interoperability with someone else's system," Levine said.

Given how long single-screen video conferencing has been around, it has enjoyed a more fruitful path to interoperability and standardization than telepresence. But even with standardization, it has much room for improvement, Bartlett said. 

Standards often have some wiggle room, but that flexibility can also lead to video conferencing and telepresence interoperability problems, he said. Even in telepresence, most vendors adopt the same standards for some functions -- such as Session Initiation Protocol (SIP) for signaling -- but often implement them in slightly different ways, he said.

That's why interoperability testing among vendors is imperative to the process, Bartlett said.

"With a standard, you can interpret the phrase one way and I can interpret the phrase another way, and it doesn't work. Computers are not forgiving in that way," he said. "[TIP] is a small piece of a much bigger puzzle. I'm sure it's a step in the right direction, but we're a long way today from [telepresence] interoperability."  

Let us know what you think about the story; email: Jessica Scarpati, News Writer.

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