10GBase-ER Explained

10 Gigabit Ethernet (10GE, 10GbE, or 10 GigE) is a networking technology for communicating Ethernet frames at a high rate of 10 Gbps. It was first defined by the IEEE 802.3ae-2002 standard. Contrast to prior Ethernet standards, 802.3ae 10 Gigabit Ethernet expresses only full duplex point-to-point links which are normally connected by network switches.

Over the years the Institute of Electrical and Electronics Engineers (IEEE) 802.3 working group has published numerous standards involving to 10GbE. Among these standards, the one which was released in 2002 called IEEE 803.2ae deals with the 10 Gbps Ethernet over fiber (10GBASE-SR, 10GBASE-LR, 10GBASE-ER, and 10GBASE-LX4). 10GBASE-SR uses multi-mode fiber using 850 nm wavelength, maximum distance of 300 m over OM3 and 400 m over OM4 fiber can be achieved. 10GBASE-LR uses single mode fiber using 1310 nm wavelength, maximum distance of 10 km can be achieved. 10GBASE-ER uses single mode fiber using 1550 nm wavelength, maximum distance of 40 km can be achieved. 10GBASE-ZR uses single mode fiber using 1550 nm wavelength, maximum distance of 40 km can be achieved. 10GBASE-ZR however is not covered in 802.3ae.

As discussed above the transmission distance of 20 km can be achieved on single mode fiber over 1550 nm wavelength using 10GBASE-ER standard. ER stands for Extended Reach, since using 10GBASE-ER standard two physically separated locations like datacenters, two different POP of any ISP, or the connectivity between service provider and the customer can be established at high speed of 10 Gbps up to 20 km.

10GBASE-ER optical transceivers are available in form factor of SFP+, XFP, XENPAK and X2 standards. 10GBASE-ER transceivers are produced by multiple vendors, being MSA compliance, the transceivers are also compatible with any network equipment. 10GBASE-ER is the only standard which can support 10 Gbps Ethernet connectivity over the maximum distance of 20 km. as already discussed 10GBASE-ZR can achieve 80 km but that is not an IEEE 802.3as standard.