SFP — Small Form-factor Pluggable
Definition
SFP (small form-factor pluggable) is a hot-swappable transceiver format, defined by industry multi-source agreements, that adapts a switch port to a fibre or copper link. SFP modules usually run at 1 Gbps, SFP+ at 10 Gbps and SFP28 at 25 Gbps, while the larger QSFP family carries 40 Gbps (QSFP+) and 100 Gbps (QSFP28). Fibre modules are built either for multimode fibre, over short distances at 850 nm, or for single-mode fibre, over long distances at 1310 or 1550 nm. For short runs between neighbouring racks, a direct-attach copper (DAC) cable, with a module fixed at each end, is a cheaper alternative.
In the field
Some switches accept only modules coded for their own brand, and an unrecognised module stays disabled or brings up no link. Modules certified by the switch manufacturer, or third-party modules tested on the actual switches before the event, avoid this problem. Both ends of a link also need the same standard, for example 10GBASE-SR at each end on multimode fibre.
Related lessons
Sources
- Cisco, 10GBASE SFP+ Modules Data Sheet : SR 850 nm multimode, LR 1310 nm et ER 1550 nm monomode, câbles DAC · cisco.com
- LINK-PP, Multimode SFP+: 10GBASE-SR Specs, Fiber Types and Use Cases : SR 850 nm sur multimode, 300 m OM3 / 400 m OM4 · resources.l-p.com
- Small Form-factor Pluggable (Wikipedia, pointeur secondaire) : SFP 1 Gbit/s, SFP+ 10, SFP28 25, QSFP+ 40, QSFP28 100 ; modules verrouillés par certains fabricants · en.wikipedia.org