What is the function of the SFP port?

- Jan 11, 2021-

What is the SFP Transceiver?

SFP optical module is a kind of interface device which converts gigabit electrical signal into optical signal. It is a standard small pluggable gigabit optical transceiver module, can be plugged into the SFP ports of network devices such as switches, routers, media converters, and used to connect optical or copper network cables for data transmission, it is commonly found in Ethernet switches, routers, firewalls, and network interface cards.

What is the SFP port?

As mentioned above, SFP ports are commonly found in network devices such as switches, routers, media converters, etc. Do you really know SFP ports? The SFP port is mainly used for signal conversion and data transmission. The port complies with the IEEE 802.3ab standard (such as 1000BASE-T) and the maximum transmission distance is 1000Mbps (the Switch’s SFP port supports 100/1000Mbps) .

SFP port advantage

The SFP port is a hot-swappable I/O interface (for input/output interface) . It is flexible and can be used in a variety of products, such as 1000BASE-SX, 1000BASE-LX/LH, 1000BASE-ZX or 1000BASE-BX10-D/u. in addition, the SFP port is downward compatible, support for 101001000mbps.

SFP port for Gigabit switch

The SFP port of a gigabit switch can be used to extend the switching capabilities of the entire network by connecting different types of fiber (such as single-mode and multi-mode fiber) and network jumpers (such as CAT5E and Cat6) , however, the SFP port of a gigabit switch must be inserted into the SFP optical module before it can be used for data transmission using fiber jumper and network jumper. All enterprise grade switches now have at least two SFP ports, which can be used to construct ring or star network topologies between different buildings, floors or areas through the connection of fiber optic cables and network jumpers. Why is the SFP Transceiver so popular?

The size of the SFP Transceiver is half that of the GBIC module, and the number of SFP ports on the same panel will be twice that of the GBIC module, according to the high density requirement of data center, SFP optical module will replace GBIC optical module in the future.

Application of SFP optical module

1.    Short range network cabling

The 1000BASE-T SFP optical module supports 10/100/1000 adaptive and Auto MDIX/MDIX, can be used with 5 types of unshielded network jumper, and the transmission distance can reach 100m.

2.    Long distance network cabling

The 1000BASE-EX and 1000BASE-ZX SFP optical modules can be used with single-mode optical fiber and are suitable for long-distance network transmission. The transmission distance of the 1000BASE-EX SFP optical module can reach 40km, and that of the 1000base-zfp optical module can reach 80km.

Note: when using single-mode fiber (SMF) over short distances, an optical attenuator is inserted into the link to avoid receiver overload.


SFP port can support both SFP Transceiver and SFP optical module. No matter what, SFP port and SFP optical module have high flexibility and compatibility in practical application, which is the best solution for Gigabit Ethernet.