SRT Trailblazes Sustainable, Efficient Data Transport

Content providers rely on protection in an unpredictable digital world

All networks, leagues, and service providers are engaged in uplinking and downlinking on a daily basis. In a digital space with its potential threats, such as privacy breaches and data corruption, these vendors proceed with caution. This is where the Secure Reliable Transport (SRT), an open-source video-transport protocol, comes in.

At the Streaming Summit at the recent NAB Show NY, Ghislain Collette, VP, product management, Haivision; Joe Mancini, senior director, product, Comcast Technology Solutions; Chris Connolly, senior director, transmission engineering and ops, NBC Sports and NBC Olympics; and Pete Thordarson, stage engineering lead, Microsoft; examined ways that SRT has improved their infrastructure and how the protocol is evolving content transport throughout the industry.

Inception and Creation
Before the protocol was created, Collette and his team at Haivision took a deep look at customer needs and the overall landscape of data transfer in 2012.

Discussing SRT at NAB Show New York’s Streaming Summit are (from left) Haivision’s Ghislain Collette, Comcast Technology Solutions’ Joe Mancini, NBC Sports and NBC Olympics’ Chris Connolly, and Microsoft’s Pete Thordarson.

“We were looking at different technologies and requirements from customers that transport any type of media regardless of the codec resolution and so on,” he told the NAB Show NY gathering. “People needed to do point-to-point, point-to-multipoint, and low-latency distribution to get feedback. We continued to look around and couldn’t find anything that was suitable in terms of performance or the business model, so we decided to create our own, which we call SRT.”

After developing prototypes in 2013, Haivision began integrating SRT with its products a year later. With multiple improvements to the system and the recruitment of Wowza as a contributor, the two companies open-sourced the network at NAB 2017.

“The idea behind open-sourcing it was really to foster the adoption,” Collette said. “If it’s good for us, it’s good for others. We wanted to create an ecosystem that anybody could work together.”

The Protocol’s Backbone
As Haivision envisioned a community-wide use of SRT, the company established a foundation with universal standards. One of these components is Automatic Repeat Request (ARQ).

“When we thought about SRT, firewall traversal was designed from the get-go,” Collette said. “Being resilient over a dirty or unpredictable network is one thing, but you never know what kind of firewall you will be dealing with.”

To avoid any increased latency issues and compromising the size of the stream or shape of the audio waveform, Haivision took the stress of buffering off the third-party user by reconstructing the content during transport.

“We wanted to keep the quality of the content in mind,” Collette explained. “It’s about preserving the integrity of the content from A to B.”

The Implementation
The end user implements this innovation in its own way. Comcast Technology Solutions, for instance, had a dated infrastructure that relied on traditional satellite transmissions. In an effort to align with the current standards of the industry, Mancini considered the advantages of SRT.

“We’ve been looking at [our strategy],” he said, adding, “How can we adapt and move towards low-latency, high-quality video delivery in a cost-effective manner? It fits really nicely within our infrastructure that we have in place today with the Comcast CDN.”

With multiple connection points along the continent of North America, Comcast puts SRT to the test with the need for smooth and reliable transport of in-house media. “With SRT, we’re able to take advantage of those locations and deploy various edge receivers out in that infrastructure,” Mancini said. “Taking advantage of the CDN infrastructure and overlaying that with a reliable UDP [User Datagram Protocol] form of transmission is where SRT really comes in for us.”

As for transmission of foreign material into the Comcast network, the company uses the point-to-multipoint function.

“We need a way to acquire those affiliate channels and other forms of content that Comcast does not deliver but maybe Comcast Technology Solutions wants access to,” he said. “Now we have all these channels that are being aggregated into one facility. If we want to deliver all those channels to one endpoint, it has to be point-to-multipoint in order to be cost-effective. SRT helps deliver the content to multiple endpoints, whether in the cloud or direct connect.”

Another example is Microsoft’s involvement with the protocol. SRT allows Microsoft to bypass the reliability test and focus on the more important task at hand.

“Sometimes,” said Thordarson, “we may put stuff over fiber if we have that availability. It may not be cost-efficient for that production, so an SRT appliance can be easily deployed. We put it in the hands of a producer that’s not an engineer, and he can plug into an internet connection that we hope is reliable and works on the air with fiber-quality transmission.”

SRT Through a Sports Lens
In a year that included such high-profile events as the PyeongChang Winter Olympics and the FIFA World Cup on Telemundo, NBC Sports tapped into the low-latency option for OTT users around the globe. Along with streaming, Haivision’s product helps facilitate other needs for the network.

“We use it quite a bit for remote ends of venues for return feeds or to get things back to us for certain events,” Connolly pointed out. “It allows us to go over the internet and have that protection against the network with the encryption element.”

In addition, SRT blends the OTT experience and the importance of a secure network.

“The protocol has also allowed us, from the digital side, to be able to bring a lot of content to a customer in a lower-cost manner,” he said. “There’s always content that people want to see that doesn’t air on a show. SRT gives us the ability to have a lower-cost and cost-effective approach with a reliable connect so we can send those things out.”

The Evolution
With more than 160 members, including 60-70 that are selling products with SRT capability, the SRT Alliance supports and promotes the protocol. The community is off to a fast start and has room for continued growth.

From a manufacturer’s standpoint, Haivision wants to constantly sharpen existing skills as well as add new ones. “We recently added the functionality of return audio channels.” Collette said. “We want to be able to build additional services for the protocol like redundancy and file transfer.”

From the end-user perspective, these companies will continue to provide a dialogue on how to deliver content at a high rate of speed without losing security.

Said Connolly, “Haivision has done a really good job at taking suggestions that we have in terms of enhancing the product, making it better, and giving us more analytic tools to help troubleshoot issues. From a production standpoint, no one ever wants to see issues. With the SRT Alliance, it gives us a lot more options.”

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