In 2014, ESPN opened Digital Center 2 (DC2) in Bristol, CT. DC2 is a $125 million, 190,000-square foot broadcast facility. The infrastructure can handle 60,000 simultaneous signals, 46 Tbps throughput, and stood as one of the first large-scale implementations of an AVB network solution. It used:
- Evertz fiber-optic routers
- Arista switches
- comms provided by Riedel
- 1,100 miles of fiber optic cable
This article continues a three-part series exploring AVB/TSN’s role and impact at ESPN. Read Part 1: Why Ethernet Audio Video Bridging?
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AVB/TSN for Audio and Video Production
When ESPN upgraded their production operations to a new facility, they wanted to ensure the new infrastructure could handle the technical demands of digital production. They chose a software-defined network approach because it allowed deterministic performance for normal broadcast operations. At the same time, this approach would bridge easily into a standard IT network infrastructure. And, even though their initial implementation of AVB/TSN focused solely on audio signal transport, an AVB network made sense for eventual implementation for both audio and video. The AVB/TSN approach would also help support the heavy production demands of a far-reaching organization like ESPN.
Production Demands
ESPN’s new facility would need to accommodate the hefty production demands of processing, editing, and broadcasting vast amounts of college and professional sporting events throughout the year. As their reach and coverage had outgrown their previous data center, they wanted to set ambitious goals for the new building:
| Concurrent Inbound Recording Paths | Content Storage Space | |
| Data Center 1 | 88 | 2,500 hours |
| Data Center 2 | 200 (initially) to 400+ (future) | 20,000+ hours |
At the same time, they set out to reduce their dependence on proprietary TV technology in exchange for the flexible commodity of IT hardware. AVB/TSN helped meet their goals by eliminating the entire proprietary baseband ingest and editing infrastructure of their previous facility, and replacing it with GPFS NAS storage and an Ethernet network. Audio / video over ethernet, and the new infrastructure could keep all real-time streams in multi-cast TS streams, and store all media in standard files (.mxf, .mp4 etc.). Additionally, all MPEG2-TS traffic could travel on a standard network.
An Infrastructure for Future Media
With AVB/TSN processing data on an Ethernet fabric topology, ESPN’s DC2 could send audio and video with the same consistency and time sensitivity, regardless of format. So, it would accommodate SD, HD, 3G, 4K, 8K, and whatever came next. More importantly, by supporting key formats of MPEG2-TS and PCM/AES, ESPN no longer needed a separate infrastructure to support audio transport. An AVB network could handle any and all compression codecs. Plus, the multi-cast capability meant all signals became available anywhere in the system.
ESPN also set itself up to become one of the first examples of a large-scale adoption of mezzanine compression with ultra low latency (ULL). That enabled a reduced bitrate for bandwidth considerations, while retaining a high quality. With switches that could handle over 30 signals per 10G port, or over 300 signals per 100G port, the AVB network could eventually offer multiple levels of compression, depending on the application.
The Final Stats
Ultimately, the final network infrastructure boasted some impressive key specs:
- Broad data scope that could eventually scale from HD to 3G to 4K video
- JPEG2000 quality and latency (already in use extensively on ESPNet)
- Less than one progressive frame delay round trip
- 2304 x 10Gbps ports resulting in 46 Tbps throughput (non-blocking)
- Support for more than 50,000 signals (compared to traditional systems which maxes out around 1,150 signals)
In Part 3, we reveal the long-term benefits of the AVB/TSN network at ESPN.
References:
Hayes, Michael. “ESPN DC2 Project Overview.” Audio Engineering Society Convention. Los Angeles Convention Center, Los Angeles, CA. October 2014. Powerpoint presentation.
Pannaman, Jonathan. “ESPN DC2 Design Philosophy.” October 2014. Powerpoint presentation.
Daley, Dan. (2014, June 10) “ESPN’S DC2 Scales AVB Large.” Retrieved from http://www.sportsvideo.org.
Photo attributed to Chrishmt0423 under the Creative Commons 2.0 Generic license.