USFPGuide

Every form factor past 1.6T

OSFP, OSFP-XD, USFP, XPO, Open CPX and co-packaged optics in one table, with lanes, capacity, cooling and who backs each.

Updated

Getting past 1.6T per port means either faster lanes, more lanes, or moving the optics closer to the chip. Each format below picks a different mix. Figures are what each MSA or its backers have published; capacity is one direction at the fastest lane rate each has announced so far.

  • OSFP 1.6T
  • OSFP-XD 3.2T
  • USFP 6.4T to 12.8T
  • Open CPX 7.2T
  • XPO 12.8T to 25.6T
One-direction capacity per module (per socket for Open CPX) at the lane rate each format has announced. The pale bar is the announced roadmap: USFP at 32 lanes, XPO at 400G per lane. Sources: the OSFP MSA, Cisco, Open CPX MSA, Arista and NAND Research.

The table

FormatWhere it sitsLanesPer lane Per moduleRoadmapHeat and coolingSwap it out front?
OSFP (OSFP1600)OSFP MSA Front-panel pluggable 8 200G 1.6T None stated More than 30 W. Air, integrated heatsink Yes
OSFP-XDOSFP MSA Front-panel pluggable 16 200G 3.2T None stated Up to 40 W. Air, taller integrated heatsink Yes
USFPCisco and NVIDIA, with TE Connectivity and Amphenol Front-panel pluggable 16 400G 6.4T 12.8T Up to 100 W. Air or liquid-cooled systems; no cold plate in the module Yes
XPOXPO MSA, led by Arista Front-panel pluggable 64 200G 12.8T 25.6T Up to 400 W. Liquid, cold plate built into the module Yes
Open CPXOpen CPX MSA (Ciena, Coherent, Marvell, Molex, Samtec, TeraHop and 39 contributors) Socketed, beside the chip 36 200G 7.2T None stated Liquid-cooling specifications in the spec Socketed, inside the box
Co-packaged optics (CPO)NVIDIA, Broadcom and others, each its own design In the switch package Whole switch 200G Whole switch None stated Part of the switch No

Open CPX's 36 lanes is our arithmetic from its 7.2T at 200G per lane. Sources at the foot of the page.

OSFP and OSFP-XD

OSFP is the workhorse of 800G and 1.6T networks: eight lanes, now at 200G, with an integrated heatsink rated above 30 W, and 32 ports fit in a 1RU switch. OSFP-XD doubles the lanes to 16 in a slightly taller module (up to 40 W), but its cages are keyed so standard OSFP modules can't go in (OSFP MSA).

USFP

Cisco and NVIDIA's format for 400G lanes: 16 lanes in an OSFP-sized module for 6.4T, 32 lanes for 12.8T, up to 100 W without a cooling circuit in the module, and a new two-dimensional connector. More on USFP.

XPO

Arista's liquid-cooled module, about 2.7 times the width of OSFP: 64 channels for 12.8T at 200G, a cold plate that cools up to 400 W, and 204.8T per OCP rack unit (Arista). USFP vs XPO.

Open CPX

Not a front-panel module: a standard socket beside the switch or GPU chip that takes replaceable optical engines, 6.4T or 7.2T each at 200G per lane (Open CPX MSA).

Co-packaged optics

The optics go inside the switch chip's package. That gives the lowest power per bit but nothing to swap from the front, and each vendor's design is its own. USFP vs co-packaged optics.

What about QSFP-DD?

QSFP-DD is the other eight-lane module of the 400G and 800G era, popular because its ports also accept older QSFP modules. Like OSFP it tops out at eight lanes, so the formats above are where the industry is going for 3.2T and up.

Sources

  1. The Next Generation of Pluggable Optical Module Solutions from the OSFP MSA (OSFP1600 and OSFP-XD), OSFP MSA, September 18, 2022.
  2. NVIDIA and Cisco Introduce New Pluggable Optics Form Factor to Scale AI Factories, Cisco Newsroom, October 12, 2026.
  3. Arista Announces XPO High Density Liquid Cooled Pluggable Optics, Arista Networks, March 12, 2026.
  4. OCP Summit: NVIDIA & Cisco Launch USFP, Comparison With NPO and XPO Roadmaps, eeFocus, October 14, 2026.
  5. Cisco and NVIDIA: Optical Ultra-Dense Small Form Factor Pluggable (USFP) Specification, NAND Research, October 13, 2026.
  6. Open CPX MSA Group Releases Specification for High Density, Pluggable CPO/NPO, Open CPX MSA (Business Wire release), September 17, 2026.
  7. NVIDIA begins shipping Spectrum-X CPO switch to select partners, TrendForce, July 27, 2026.