Thomson Explains: SMPTE 2110 - Part 5

The SMPTE ST 2110 suite of standards enables professional media transport over IP networks, offering scalability and flexibility for modern broadcast facilities. This article explores real-world deployment architectures, drawing on case studies like the WTTG/WDCA IP-based station, OB trucks, and hybrid SDI/IP integrations to highlight design considerations, challenges, and strategic insights for engineers.

Large-Scale IP Broadcast Facilities

The transition to IP-based workflows is exemplified by the WTTG/WDCA Fox Television duopoly in Washington, D.C., a real-world implementation of SMPTE ST 2110 for a new facility in Bethesda, Maryland, completed in 2021. Key architectural elements include:

• Spine-Leaf Network Topology: The facility employs a spine-leaf architecture, where top-of-rack leaf switches connect devices, and high-bandwidth spine switches link the leaves, forming a scalable, non-blocking core. Each studio has a dedicated leaf switch, connected to spine switches at 100 Gbps, ensuring capacity for current HD and future UHD streams. Engineers must understand redundancy mechanisms, such as rerouting if a spine link fails, to maintain system reliability.

• Redundant Networks: WTTG/WDCA uses identical “red” and “blue” networks for RTP media streams, adhering to SMPTE ST 2022-7 for seamless failover. A separate “purple” network handles audio monitoring and control. Engineers must monitor both networks to detect packet loss early, as failover masks single-path failures, but a second failure could disrupt broadcasts. Clear documentation of red and blue interfaces is critical.

• System Scale and Automation: The facility manages approximately 500 endpoints, supporting 700 video flows, 800 audio flows, and 300 ancillary flows, far exceeding traditional SDI router capacities. Automation via Networked Media Open Specifications (NMOS) is essential, as manual configuration of thousands of flows is impractical. Engineers should leverage scripts or control software to streamline device management.

• Unified Control and Monitoring: A broadcast controller integrates IP streams, SDI routers, multiviewers, and legacy systems, ensuring operators experience seamless routing regardless of signal type. Engineers must configure control interfaces to abstract IP complexity and implement unified monitoring dashboards for PTP, network, and video signal health.

• Testing and Commissioning: WTTG/WDCA conducted end-to-end testing before a “flash cut” to the new IP plant. This approach, ideal for greenfield builds, allows simulation of failure scenarios and verification of failover behavior. Engineers assist by gathering performance data and ensuring device redundancy, a shift from traditional cable-by-cable testing.

OB Trucks and Flypacks

IP-based OB trucks and flypacks, used for live events like sports or concerts, leverage SMPTE ST 2110 for flexibility and reduced cabling. Key considerations include:

• All-IP OB Trucks: Modern OB trucks use ST 2110 cores with high-capacity switches linking cameras, replay systems, and switchers. This allows reconfiguration without rewiring, enabling a single truck to handle diverse events. Multiple trucks or flypacks can connect via fiber, forming a distributed system, limited only by switch port capacity.

• Inter-Truck Connectivity: Connecting multiple IP systems requires a single PTP master clock, achieved by designating one truck’s grandmaster or syncing to a venue’s clock. Multicast routing, often via PIM or a common switch, ensures streams are shared across networks. Engineers must verify PTP election and multicast configurations to prevent issues like missing feeds.

  • Arista has a great white paper going into detail about how they’re about to get T2T to work in an all-IP world.

    • https://www.arista.com/assets/data/pdf/SMPTE-ST2110-OB-truck-interconnectivity-Deployment_Guide.pdf

• Remote Production: OB units increasingly send feeds to base studios over IP, many times using JPEG-XS (-22) compression for bandwidth efficiency. Engineers manage on-truck networks and WAN interfaces, ensuring security through firewalls to protect NMOS and PTP traffic.

• Flypack Efficiency: Flypacks reduce cabling by aggregating signals over fiber. Engineers must configure switches and endpoints rapidly on-site, using pre-assigned IP pools and automation scripts to add devices like cameras to NMOS, minimizing setup errors under time constraints.

Hybrid SDI/IP Integration

Integrating IP systems with legacy SDI or TDM-based facilities presents unique challenges:

• Signal Conversion: Gateway devices convert IP streams to SDI and vice versa, but conversions add latency and potential failure points. Engineers must ensure redundancy in gateways and monitor latency, particularly for time-sensitive signals like talkback audio.

• Clock Synchronization: IP systems use PTP, while legacy systems rely on black burst. Locking the IP system’s grandmaster to the station’s reference minimizes latency and ensures in-phase signals. Frame synchronizers are a less ideal alternative due to added delay.

• Audio Interoperability: Bridging IP-based audio (e.g., AES67) with TDM-based fabric or MADI systems requires analog tie-lines or specialized bridges. Engineers must manage audio levels and synchronization to avoid issues like ground loops or latency.

• Scalability and Coordination: In campus-wide IP migrations, studios and trucks connect to a core switch fabric. Engineers coordinate IP addresses and multicast ranges to prevent conflicts, following JT-NM and AIMS guidelines for interoperability.

Strategic Considerations

• Latency vs. Quality: IP systems introduce minimal latency while maintaining uncompressed quality. JPEG-XS compression reduces bandwidth considerably with a negligible latency hit, but HEVC does introduce a meaningful delay. Ensure you perform careful latency budgeting for live production.

• Redundancy: Beyond network redundancy, dual PTP masters and mirrored nodes enhance reliability. Engineers must design and implement rerouting mechanisms for device failures.

• Legacy Backups: Early IP deployments often retain SDI backups for critical signals, phased out as confidence grows. Engineers maintain both systems in parallel during transitions.

• Training and Workflows: Engineers adopt network admin skills (e.g., Wireshark for troubleshooting), while operators learn new interfaces. Clear status displays build trust in IP systems.

• Interoperability: JT-NM Tested programs ensure multi-vendor compatibility. Engineers should verify new devices’ compliance to avoid integration issues.

Case Study Highlights

• WTTG/WDCA: A fully IP plant with redundant networks and comprehensive pre-launch testing. Troubleshooting focuses on software-based flow monitoring rather than physical cables.

• OB Trucks: IP trucks enable distributed production, requiring simplified operator workflows and new fault-finding approaches via network monitoring.

• Hybrid Integration: IP and baseband systems interface through gateways, with synchronized clocks ensuring reliable signal handoff.

Conclusion

SMPTE ST 2110 enables scalable, flexible broadcast workflows, as demonstrated by WTTG/WDCA, OB trucks, and hybrid integrations. Engineers must combine IP and baseband expertise, leverage automation, and anticipate failure scenarios to ensure reliability.

As of 2025, the industry’s shift toward IP and hybrid systems underscores the need for engineers skilled in network management, signal integrity, and interoperability to deliver seamless on-air results.