The connector is the physical interface between the cable and the transceiver. At AI cluster scales, connector selection determines fiber count per run, cabling density, and termination cost.

LC Connector

The LC (Lucent Connector) is a duplex connector -- two fibers, one for TX and one for RX. It is used with long-reach SMF transceivers (FR4, LR4). An LC connector handles a single 400G lane when used with WDM technology, or a full 400G link for FR4 modules (which multiplex four wavelengths over two fibers using WDM).

LC is familiar from enterprise networking and is the right connector when a single fiber pair carries a complete high-speed link.

MPO / MTP Connector

MPO (Multi-fiber Push On) is the connector standard for multi-fiber assemblies. A single MPO connector can carry 8, 12, 16, or 24 fibers. MTP is Corning's brand name for an MPO connector -- same physical standard, marginally different mechanical characteristics in some variants. The two names are used interchangeably in the field.

For AI cluster AI fabric cabling, MPO dominates:

MPO-12 carries 12 fibers. Used with DR4 transceivers: 4 TX fibers + 4 RX fibers (8 fibers active, 4 fibers unused in each MPO-12 plug). The 500m cross-row runs in large data halls use MPO-12 cable assemblies.

MPO-16 carries 16 fibers. Used with SR8 transceivers: 8 TX fibers + 8 RX fibers. All 16 fibers are active. The intra-row connections in MMF-based deployments use MPO-16 assemblies.

Trunk cable systems

At SuperPOD scale -- 256 DGX nodes, thousands of individual fiber runs -- managing per-link cable assemblies is operationally impractical. Trunk cable systems are the standard solution.

A trunk cable bundles multiple MPO-to-MPO fiber runs into a single sheath, typically 12, 24, or 48 fibres per trunk. Pre-terminated trunk assemblies are factory-built, tested, and shipped ready to plug in. The two ends are labeled with their port assignments -- no field splicing, no field termination, no field testing.

A fully deployed DGX SuperPOD has:

• 256 DGX nodes x 8 NIC ports = 2,048 server-to-leaf runs
• 8 leaf switches x 32 spine uplinks each = 256 leaf-to-spine runs
• Total: approximately 2,300 individual cable runs

These are physically organised into trunk bundles that run through overhead trays or raised floor systems. Structured cabling with pre-terminated trunks is the only way to make this scale manageable. A single technician can install a 48-fiber trunk in minutes; hand-terminating 48 individual LC or MPO connectors in the field would take hours and introduces field quality risk.