SFP+ module - Definition

An SFP+ (Small Form-factor Pluggable Plus) module is a compact, interchangeable plug-in module that enables network connections typically at 10 Gbit/s. It is inserted into compatible network devices such as switches, routers or servers and is used for data transmission via fibre-optic or copper connections. As a further development of the classic SFP module, SFP+ offers higher bandwidth whilst retaining an almost identical form factor. The modules are primarily used in corporate networks, data centres and for high-performance server connections.

How does an SFP+ module work?

An SFP+ module is inserted into a suitable slot on the network device. In the case of optical modules, electrical signals are converted into light signals, which are transmitted via fibre-optic cables. Copper-based variants, on the other hand, enable electrical data transmission. The modules are generally hot-swappable and can therefore be replaced whilst the network device is switched on. However, the network connection in question is briefly interrupted during this process.

SFP, SFP+ and SFP28: An overview of the differences

The three module variants differ primarily in terms of their typical transmission speeds.

Important: Depending on the network device, an SFP+ port may also support 1 Gbit/s SFP modules. Conversely, 10 Gbit/s SFP+ modules do not normally work in pure 1 Gbit/s SFP ports. The manufacturer’s specifications and the supported port speeds are decisive.

What types of SFP+ modules are available?

Different variants are used depending on the required range and the existing cabling.

• SFP+ SR (Short Range): For multimode fibre, for example up to 300 m with OM3 or 400 m with OM4.
• SFP+ LR (Long Range): For single-mode fibre and distances typically up to 10 km.
• SFP+ ER (Extended Range): For longer single-mode connections, typically up to 40 km.
• SFP+ RJ45: Enables 10 Gbit/s Ethernet over suitable copper network cables. The range depends on the module and the cabling.

Are all SFP+ modules compatible with every switch?

No. As well as requiring the correct slot, the modules must be supported by the respective network device. Some manufacturers require specific approvals or compatible module identifiers.

What is the difference between SFP+ and a DAC cable?

An SFP+ transceiver requires a separate fibre-optic or copper cable. A DAC (Direct Attach Copper) cable, on the other hand, has permanently integrated connectors and is particularly suitable for short connections between network devices, for example within a server rack.