Different Types, Features and Advantages of Cisco Gigabit Ethernet SFP Modules

SFP stands for Small Form-factor Pluggable. It is widely used in the field of Data Communication and Networking. Small Form-Factor Pluggable (SFP) Gigabit Interface Converter is a hot swappable I/O device that plugs into a Gigabit Ethernet port or slot, linking the port with the network. These SFPs mainly acts as an interface between a networking device like any Switch, Router, Repeater, Multiplexer etc and its interconnecting cable. The interconnecting cable may be made of copper or it can be an optical fiber cable.

Certain SFP also use copper cables as interface. This will cause a device in the network to send their data over shielded or unshielded twisted pair cable. Usually such copper cable interfaces are used when the information to be transmitted needs to cover only shorter distances where use of copper cable is more economical than optic fiber cables. Find copper and Fiber SFPs in figures below.

Types of Cisco SFP modules

Types of Cisco Gigabit Ethernet SFP Modules:

SFP transceivers are of various types and each type comes with different configurations of transmitter and receiver. It is important to choose a proper transceiver to act as an interface between the device and the cable. This choice of transceiver is usually made based on the type of fiber optic cable. Such SFP transceivers which are used to provide the necessary reach to a fiber optic cable are categorized as optical SFP. These SFP modules are of several versions, wherein each version has different values of working wavelength and working distance.

SFPs can be used and interchanged on a wide variety of Cisco products and find below properties of different Cisco SFPs 1000BASE-T, 1000BASE-SX, 1000BASE-LX/LH, 1000BASE-EX, 1000BASE-ZX, or 1000BASE-BX10-D/U on a port-by-port basis.

Cisco Gigabit Ethernet RJ45 SFP Modules

Fig.Cisco RJ45 SFP module





 1000BASE-T SFP:

1000Base-T SFP is used for Copper networks. The 1000BASE-T SFP operates on standard Category 5 unshielded twisted pair copper cabling of up to 100m length. Cisco 1000BASE-T SFP modules support 10/100/1000 auto negotiation and Auto MDI/MDIX.

Cisco Gigabit Ethernet SFP Fiber Modules

Fig. Cisco Gigabit Ethernet SFP Module







1000Base-SX SFP supports Multimode fiber only. The 1000BASE-SX SFP compatible with the IEEE 802.3z 1000BASE-SX standard. It operates on legacy 50 μm multimode fiber links up to 550 m, up to 1km over laser-optimized 50 μm multimode fiber cable and on 62.5 μm Fiber Distributed Data Interface (FDDI)-grade multimode fibers up to 220 m.


1000BASE-LX/LH SFP compatible with the IEEE 802.3z 1000BASE-LX standard and it supports for both Multimode and single-mode Fibers. 1000BASE-LX/LH SFP operates on standard single-mode fiber-optic link spans of up to 10 km and up to 550 m on any multimode fibers.


The 1000BASE-EX SFP supports for Single-Mode Fibers. 1000BASE-EX SFP operates on standard single-mode fiber-optic link length up to 40 km. A 5-dB inline optical attenuator should be inserted between the fiber-optic cable and the receiving port on the SFP at each end of the link for back-to-back connectivity.


The 1000BASE-ZX SFP operates on standard single-mode fiber-optic link spans of up to approximately 70 km in length. The SFP provides an optical link budget of 23 dB, but the precise link span length depends on multiple factors such as fiber quality, number of splices, and connectors. When shorter distances of single-mode fiber (SMF) are used, it might be necessary to insert an inline optical attenuator in the link to avoid overloading the receiver. A 10-dB inline optical attenuator should be inserted between the fiber-optic cable plant and the receiving port on the SFP at each end of the link whenever the fiber-optic cable span loss is less than 8 dB.

1000BASE-BX10-D and 1000BASE-BX10-U SFP:

The 1000BASE-BX-D & 1000BASE-BX-U SFPs used for Single-Fiber Bidirectional applications, compatible with the IEEE 802.3ah 1000BASE-BX10-D and 1000BASE-BX10-U standards. The 1000BASE-BX-D & 1000BASE-BX-U SFPs operates on a single strand of standard SMF. A 1000BASE-BX10-D device is always connected to a 1000BASE-BX10-U device with a single strand of standard SMF with an operating transmission range up to 10 km.

The communication over a single strand of fiber is achieved by separating the transmission wavelength of the two devices. 1000BASE-BX10-D transmits a 1490-nm channel and receives a 1310-nm signal, whereas 1000BASE-BX10-U transmits at a 1310-nm wavelength and receives a 1490-nm signal. Wavelength-division multiplexing (WDM) splitter integrated into the SFP to split the 1310-nm and 1490-nm light paths.

The GLC-BX-D and GLC-BX-U SFPs also support digital optical monitoring (DOM) functions according to the industry-standard SFF-8472 multisource agreement (MSA). This feature gives the end user the ability to monitor real-time parameters of the SFP, such as optical output power, optical input power, temperature, laser bias current, and transceiver supply voltage.

These SFP transceivers will soon replace all the existing interface standards in networking because of their compactness, flexible and economical design and high performance.


Fig. Cisco SFP modules Connections


Filed Under: WAN


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