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Bahasa Melayu SFP-DD
Đội ngũ của chúng tôi đang thực hiện bản dịch. Bài viết này tạm thời chưa có bản tiếng Việt và đang được hiển thị bằng tiếng Anh.
SFP Double Density (SFP-DD) adds a second row of contacts to the SFP connector, giving two electrical lanes in the SFP footprint. At 2×50G PAM4 that is 100 Gb/s in a port the size of a 1G SFP — while the same cage still accepts ordinary single-lane SFP/SFP+/SFP28/SFP56 modules.
Key facts
| Lanes × rate | 2 × 25G (NRZ) or 2 × 50G (PAM4) |
| Total | 50G / 100G |
| Connector | LC duplex, SN/CS duplex; SFP-DD DAC/AOC |
| Supply | 3.3 V, higher power class than SFP56 |
| Applications | 100G server access in SFP footprint, 2×50G breakout |
Specifications
- SFP-DD MSA hardware specification — mechanical, electrical, thermal and the double-row connector.
- SFP-DD MIS — Management Interface Specification, Rev 2.0 (2020): the management model for two-lane SFP-DD modules over a two-wire interface. See MIS.
Management interface
SFP-DD leaves the SFF-8472 two-address model behind. MIS follows the CMIS approach — lower memory always accessible, paged upper memory, per-lane data-path control — adapted to two lanes. Identity codes come from SFF-8024. In practice a host must speak MIS to bring up an SFP-DD module; a legacy SFP inserted in the same cage is read with SFF-8472 as usual.
Compatibility notes
- Backward compatible cage: SFP-DD ports accept SFP, SFP+, SFP28 and SFP56.
- SFP-DD is the two-lane counterpart of QSFP-DD (eight lanes) — the same "double density" idea applied to the small footprint.
In CodingBox
CodingBox supports MIS 2.0 and decodes SFP-DD modules with the MIS layout — identity, per-lane diagnostics and configuration pages — while single-lane modules in the same family fall back to SFF-8472 automatically.