In order to accelerate speeds from 100 Mbps Fast Ethernet up to 1 Gbps, many changes have been made to the physical interfaces. Gigabit Ethernet uses the same 802.3 frame format as 10Mbps and 100Mbps Ethernet systems. It runs ten times faster than the speed of Fast Ethernet, backward compatibility is assured with earlier versions, increasing its attractiveness by offering a high bandwidth connectivity system to the Ethernet family of devices.
Defined by IEEE 802.3z standard, Gigabit Ethernet originally launched three different physical layers: 1000Base-LX and 1000Base-SX using fiber and 1000Base-CX using copper. These physical layers were originally developed by IBM for the ANSI Fibre Channel systems and used 8B/10B encoding to reduce the bandwidth required to send high-speed signals. The IEEE merged the fibre channel to the Ethernet MAC using a gigabit media independent interface (GMII), which defines an electrical interface, enabling existing fibre channel PHY chips to be used and enabling future physical layers to be easily added.
1000Base-SX is a physical layer specification for Gigabit Ethernet over fiber optic cabling as defined in IEEE 802.3z. SX stands for short wavelength. And 1000Base-SX uses short wavelength laser (850nm) over multimode fiber as opposed to 1000Base-LX, which uses long wavelength laser over both multimode and single-mode fiber. The maximum distance of (multimode) fiber, based on 1000Base SX is 550m.
This Gigabit Ethernet version was developed for the short backbone connections of the horizontal network wiring. The SX systems operate full-duplex with multimode fiber only, using the cheaper 850nm wavelength laser diodes. The maximum distance supported varies between 200 and 550 meters depending on the bandwidth and attenuation of the fiber optic cable used. The standard 1000Base-SX NICs available today are full-duplex and incorporate LC fiber connectors.
SFP transceiver is a hot-swappable input/output device that plugs into a Gigabit Ethernet port/slot, linking the port with the fiber-optic network. SFP can be used and interchanged on a wide variety of Cisco products and can be intermixed in combinations of IEEE 802.3z compliant 1000Base-SX interfaces on a port-by-port basis. 1000BASE-SX SFP (eg. Cisco GLC-SX-MM) supports link length of up to 550m on multimode fiber at 1Gbps. This optic works at 850nm wavelength and uses a LC connector.
SFP modules have now become an indispensable component in networks. Thus, it is very necessary to use quality assured modules. If you want to purchase cheaper and 100% compatible 1000Base-SX SFP modules online, FS.COM may be your good choice. You would not worry about the compatibility of the optics you have bought here. Because there is a perfect system from the production to shipment. Compatible SFP transceiver modules offered by FS.COM are test-assured and fully compatible with major brands (such as Cisco, HP, NETGEAR, Finisar, Juniper, etc.) and supported by a lifetime warranty. Besides, all these SFP modules can be customized according to your specific requirements.