Physical Media Dependent

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Physical Medium Dependent sublayers or PMDs were defined by the IEEE 802.3ae task force in 2002. These sublayers define physical layer specifications in 10 Gigabit Ethernet transmissions.

[edit] The Physical Medium Dependent Sublayers (PMDs)

10GBASE-E: has been defined for single mode fiber operations only. It operates in the 1550 nm band allowing for distances of up to 40 km to be reached.

10GBASE-L: was also defined for single mode fiber operations, uses the 1300 nm band allowing it to reach up to 10 km.

10GBASE-S: was defined for use in multimode fiber and ultimately costs less than the other 10GbE standards. It uses 850 nm lasers and only reaches distances ranging between 26 to 82 metres on older fiber technology. In newer optimized multimode fibers (a.k.a OM3) it can reach up to 300 m.

10GBASE-LX4: uses four lasers that each transmit at 3.125 Gbit/s. The receiver is arranged in a wavelength-division multiplexing manner. On legacy FDDI multimode fiber it can reach up to 300 m while on single mode fiber it can reach up to 10 km.

After these specifications have been laid out they are then placed in to LAN and WAN specifications using three different Physical Coding Sublayer standards.