Study Plan
2110 Topo
SMPTE ST 2110 represents a fundamental shift in professional broadcast media transport from baseband SDI
(a point-to-point, synchronous, circuit-switched system) to an IP-based, packet-switched, asynchronous network. It doesn't "change" the OSI model itself
—the 7-layer stack remains the same—but it leverages the full IP stack (Layers 1–4 primarily) in ways that were irrelevant or minimal in traditional SDI-based facilities.
| OSI Layer | Traditional Baseband SDI | SMPTE ST 2110 (IP-Based) | What 2110 Emphasizes (New or Critical Importance) |
|---|---|---|---|
| Layer 7 (Application) | Direct hardware processing (e.g., embed/de-embed audio) | Separate essence streams; NMOS for discovery/control | Flexible workflows, but not core to transport |
| Layer 6 (Presentation) | Fixed multiplexing of video/audio/anc | RTP payload formats for separate essences | Essence separation enables independent processing |
| Layer 5 (Session) | N/A (continuous stream) | RTP timestamps + SDP for session description | Precise coordination of separate streams |
| Layer 4 (Transport) | N/A (bit-serial) | UDP (unreliable, low-latency) + RTP | Critical: No TCP retransmission; relies on network reliability |
| Layer 3 (Network) | N/A (no routing) | IP + Multicast (IGMP/PIM) | Highly emphasized: Routing, addressing, multicast subscription for efficient distribution |
| Layer 2 (Data Link) | Point-to-point (coax/fiber) | Ethernet (MAC, switches) | Highly emphasized: High-bandwidth (10/25/100G), low-jitter switches; QoS |
| Layer 1 (Physical) | Coax/fiber with fixed timing | Ethernet cabling (often fiber) | Reliable, high-speed media; still important but commoditized |
What 2110 Emphasizes That Wasn't Important (or Didn't Exist) Before In SDI facilities, the Physical Layer (Layer 1) dominated everything: point-to-point cables, fixed synchronous timing (blackburst/genlock), and hardware routers. Higher layers were essentially bypassed.
With ST 2110:
Layers 2 and 3 (Data Link & Network) Become Central:
Broadcast engineers now must deeply understand Ethernet switching, multicast routing, IGMP snooping, and IP addressing.
Routing is dynamic and distributed (devices subscribe to multicast flows via IGMP), replacing centralized SDI matrix routers.
Network design (non-blocking switches, leaf-spine topology, QoS prioritization) is critical for deterministic performance.
Precise Timing and Synchronization (Cross-Layer, Especially Layers 1–4): SDI was inherently synchronous (everything locked to the same clock). 2110 uses PTP (IEEE 1588 / SMPTE ST 2059) over the network for grandmaster clock distribution—timing is now a network service, not a separate video signal. RTP timestamps align separate essences; traffic shaping (ST 2110-21) controls packet pacing to avoid bursts/jitter.
Layer 4 (UDP/RTP) Constraints: No reliable transport like TCP (too much latency/retransmission). Networks must be engineered for near-zero packet loss; seamless protection (ST 2022-7) duplicates flows.
Separation of Essences: Video (2110-20), audio (2110-30/AES67), anc data (2110-40) are independent streams. This enables flexible routing/processing but requires robust upper-layer management (e.g., NMOS for discovery/connection).
In summary, ST 2110 elevates networking expertise (Layers 2–4) to the forefront of broadcast engineering, while the Physical Layer becomes more of an IT commodity (high-speed Ethernet). The biggest mindset shift: from "wiring video signals" to "designing and managing a real-time media network." This enables scalability, remote production, and efficiency—but demands new skills in IP networking, timing, and multicast that were largely irrelevant in the SDI era.
