Differences between 10G SFP and 10G SFP+
Apr. 10, 2023
As we know, SFP modules just look the same as SFP+ modules. Most switches can support both SFP modules and SFP+ modules. So, do these two modules really refer to the same module and what is the difference between SFP and SFP+?
SFP vs SFP+: SFP definition
SFP stands for Small Form Factor Pluggable. SFP specifications are based on IEEE 802.3 and SFF-8472. they are capable of supporting speeds of up to 4.25 Gbps. Due to their small size, SFPs replace the previously common Gigabit Interface Converter (GBIC). By selecting different SFP modules, the same electrical port on the switch can be connected to different fibre types (multimode or single mode) and different wavelengths.
SFP vs SFP+: SFP+ definition
As the SFP only supports up to 4.25 Gbps, the SFP+, which supports data rates up to 16 Gbps, was later introduced. The SFP+ specification is based on SFF-8431. In most applications today, SFP+ modules typically support 8 Gbit/s Fibre Channel, 10G Ethernet and the optical transport network standard OTU2. SFP+ modules are the most popular 10G Ethernet modules on the market.
SFP vs SFP+
Looking at the definitions of SFP and SFP+ mentioned above, we can see that the main difference between SFP and SFP+ is the data rate. And because of the different data rates, the applications and transmission distances are also different.
You'll find these three common 10G SFP+ module types - SFP-10G-SR, SFP-10G-LRM and SFP-10G-LR - commonly used for optical fibre.
SFP refers to small modules that can be hot-swapped. 10G means they have a maximum transmission rate of 10.3 Gbps for 10 Gigabit Ethernet. SR, LRM, and LR represent the transmission distance of 10G optical modules. The transmission distances they represent range from short to long.
The SFP-10G-SR is a 10GBASE-SR SP+ module with a distance of up to 300 metres with OM3 multimode fibre (MMF), claimed to be the lowest cost and lowest power consumption VCSEL module.
The SFP-10G-LR is a 10GBASE-LR SP+ module with a distributed feedback laser (DFB). It operates at a nominal wavelength of 1310nm and has a transmission distance of up to 10km over single-mode fibre (SMF). It is used for wiring buildings on large campuses and even for setting up metropolitan area networks (MAN).
The SFP-10G-LRM is a 10GBASE-LRM module that supports a link length of 220m over standard Fibre Distributed Data Interface (FDDI) class multimode fibre. To ensure that the FDDI class, OM1 and OM2 fibre specifications are met, the transmitter should be coupled via a mode conditioning jumper. applications on OM3 or OM4 do not require a mode conditioning jumper.
What is a QSFP port?
The QSFP or Quad Small Pluggable Transceiver is another type of compact hot-swappable transceiver. It supports Ethernet, Fibre Channel, InfiniBand and SONET/SDH standards with different data rate options. QSFP modules are typically available in several different types: 4x1Gbps QSFP, 4x10Gbps QSFP+, and 4x28Gbps QSFP28.
QSFP+ and QSFP28 are the latest versions and support a wide range of 40Gbps and 100Gbps applications. The QSFP specification is based on the SFF-8436.
How do I choose an SFP transceiver?
In addition to SFP, SFP+ and QSFP, you also need to consider the application. there are different types of SFP transceivers, depending on their use, such as single mode and multimode SFP. singlemode SFP transceivers work with single-mode fibre, while multimode SFPs are compatible with multimode fibre. There are also long-range WDM SFP transceivers for multiplexing, simplex SFPs for single-fibre applications, video SFP transceivers for transmitting HD video, and PON SFP transceivers for fibre-based access networks. SFPs are available for commercial and extended operating temperature ranges, with or without extended diagnostic capabilities.
The Small Form Factor Pluggable specification is published in the SFP Multisource Protocol and allows you to mix and match components from different vendors. However, some IT equipment manufacturers sell network equipment that only supports vendor-specific SFPs. To ensure compatibility, check the vendor's optical test centre or ask your vendor to verify compatibility.
Need help choosing between SFP and SFP+ QSFP? Contact Hilink for expert advice on network transceivers.