XFP

XFP (10 Gigabit Small Form Factor Pluggable) was the first mainstream 10G module. It integrates the clock-and-data recovery inside the module and talks to the host over a clean serial XFI interface — which made it protocol-agnostic and host-friendly, but larger and hotter than the SFP+ that eventually displaced it.

Key facts

Specifications

• INF-8077 — 10 Gigabit Small Form Factor Pluggable Module, Rev 4.5: mechanical, electrical (XFI) and the XFP management interface.
• Contemporaries of the same era: INF-8476 (X2) and INF-8474 (XENPAK).

Management interface

XFP defines its own memory map in INF-8077i, at address A0h with a lower memory area and selectable upper tables (Table 01h holds serial ID, thresholds live in lower memory, and so on). It is not SFF-8472 and not SFF-8636 — an XFP must be decoded with the INF-8077i map or every field is misread.

XFP includes digital diagnostics (temperature, bias, Tx/Rx power, supply voltages) and, on DWDM variants, wavelength tuning registers.

Compatibility notes

• Not mechanically or electrically compatible with SFP+.
• Because the CDR is inside the module, XFP hosts are simpler; the trade-off is module power and size, which is why SFP+ won for dense switching.

In CodingBox

CodingBox decodes XFP with the INF-8077i map — identity, thresholds and DDM from the correct tables — and edits and writes them with checksums recalculated. XFP is one of the five MSA specification families the application supports.