Cisco CFP-100G-ER4The Cisco CFP-100G-ER4 is a 100GBASE-ER4 Ethernet fiber adapter at 100 gigabit per second speed.

The CFP-100G-ER4 is designed for use at distances of up to 40 km, This is enough to handle metropolitan area networking easily. Urban centers can easily be interconnected with 40km class fiber systems.

Fiber uses separate TX and RX links so connections are in pairs of cables to provide full duplex service.