ESPN’s DC2 Scales AVB Large

For everything that ESPN’s new Digital Center 2 (DC2) is — and at 194,000 sq. ft. of seriously advanced broadcast and postproduction technology, it’s a lot — the facility, which cost a reported $125 million and opened in June in Bristol, CT, is also a huge bet on Audio-Video Bridging (AVB), the standards-based approach to packetized digital signal transport that is making its presence felt in an industry increasingly oriented toward Ethernet networked-based workflows.

“The audio infrastructure here is primarily AVB,” says Jonathan Pannaman, senior director of technology, ESPN. “We have a little MADI transport in parts, but even that will be converted to AVB at some point. The entire comms infrastructure is all AVB, from the [router] core to the panels.”

DC2’s design is predicated largely on stream-based production, and it has a massive router core to support. Featuring two Evertz EXE fiber-optic routers, with a throughput of 46 Tbps, it can handle upwards of 60,000 signals simultaneously over the plant’s 1,100 miles of fiber. Inside the core, audio can be either embedded in video or a standalone signal, available instantly to engineers in any of the Lawo mc2-56 audio consoles in DC2’s four audio-control rooms, which are fitted with AVB interfaces. The AVB infrastructure replaces ESPN’s previous all-MADI audio-transport system, one that stood apart from Bristol’s video-signal transport. In DC2, audio and video signals are available on any channel at any time, always synchronized via AVB’s clocking.

Choosing AVB
ESPN’s extensive implementation of AVB in DC2 comes at a time when digital networking has reached its tipping point, with a proliferating number of proprietary and standards-based systems competing in the market. Pannaman says, although research made the company confident that AVB is the right choice for DC2’s infrastructure, implementing it on such a vast scale was challenging.

“We’re not concerned over the technology but more about the fact that it was so new and, as a result, there were few large-scale products available for it at the time,” he explains.

In fact, he suggests, the scale of DC2 may actually have “stimulated” accelerated product development and testing by manufacturers supporting AVB.

This year, the AVnu Alliance, the trade organization tasked with certifying the interoperability of every AVB-product candidate, has stated that the number of products undergoing evaluation has increased significantly. Switches in particular were critical for designing and then building DC2’s network infrastructure, says Pannaman. Arista Networks Ethernet AVB switches are used extensively.

None of the proprietary networking systems were ever considered for DC2, he adds. “We were looking to do things that benefit our goals here but also as part of a much larger organization,” he says, referring to DC2’s context within ESPN and parent company Disney’s own extensive media-technology infrastructures. “This is a network within an enterprise, so it needs to have reach. If you want guaranteed signal performance, you need the kinds of sync and bandwidth that AVB provides.”

All the audio-systems vendors agreed to make provisions for an AVB interface for their platforms, including Evertz, comms provider Riedel, and Lawo (which is also a backer of Ravenna, another open-standards IP-based network). However, Pannaman points out that product and system choices were based on the operations group’s “enthusiasm” for various devices: “They have to work with these every day, so that came first.”

The implementation of AVB in ESPN’s DC2 is focused solely on audio-signal transport initially, but Pannaman says the intention is to have it encompass video signals as well in the future. “Audio is just phase one,” he says, to be followed by video and then control-signal data, until the center’s Ethernet network reaches the kind of singularity that AV and IT mavens dream about.

“We have the capacity and the throughput to handle it all, eventually,” he says. “It will have tremendous implications for workflow.”