A sixteen-lane extension of OSFP, aimed at 1.6T and 3.2T without waiting for the next SerDes generation.
What Is OSFP-XD?
OSFP-XD — extra dense — doubles OSFP's electrical lane count from eight to sixteen. That gives 1.6T using the 100G-per-lane SerDes that already exist, rather than requiring 200G lanes, and provides a path to 3.2T once 200G lanes are mainstream.
It is the brute-force answer to the same question OSFP224 answers elegantly: how do you double port bandwidth? OSFP224 doubles the lane rate; OSFP-XD doubles the lane count.
What Sixteen Lanes Costs
Sixteen lanes means sixteen optical channels, which means a great deal of fibre per port. A parallel OSFP-XD module can need a thirty-two-fibre interface, and the cabling implications are substantial — this is one of the drivers behind sixteen-fibre MPO and the very-small-form-factor connector families.
Power scales with lane count too. A sixteen-lane module is not cheap in watts, and the thermal design of the cage matters as much as the module. Model it before committing to a rack layout.
Which One Wins
Whether OSFP-XD or OSFP224 dominates at 1.6T depends largely on how quickly 224G SerDes reach volume in switch silicon. Both are being built, and both reach 1.6T, so the decision is made by what your platform's SerDes can do rather than by any inherent superiority.
For cabling, the low-regret move is base-16 MPO plant. Sixteen divides cleanly by eight, so it serves both a sixteen-lane and an eight-lane 1.6T module without stranding fibre — see base-8 vs base-12 vs base-16.
OSFP-XD reference
| Lanes | 16 |
|---|---|
| 1.6T | 16 × 100G PAM4 |
| 3.2T | 16 × 200G PAM4, once 224G SerDes are mainstream |
| Body | OSFP-derived, larger contact array |
| Fibre for a parallel module | up to 32 — MPO-32 or dual MPO-16 |
| Trade-off | high fibre count and high power per port |