Ethernet in the First Mile
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Ethernet in the First Mile (EFM), also known as IEEE 802.3ah, is a collection of protocols specified in IEEE 802.3, defining the Ethernet in the Access Networks, i.e. First/Last Mile.
With Wide, Metro and Local Area Networks already standardized, the EFM allows continuous standard Ethernet network across the globe, eliminating non-native transport such as Ethernet over ATM from the Access Networks.
EFM defines how Ethernet can be transmitted over new media types:
- Voice-grade copper. These new EFM copper (EFMCu) interfaces allow optional multi-pair aggregation
- Long wavelength single fiber (as well as long wavelength dual-strand fiber)
- Point-To-Multipoint (P2MP) fiber. These new interfaces are known under collective name Ethernet over Passive Optical Networks (EPON).
EFM also addresses other issues, required for mass deployment of Ethernet services, such as Operations, Administration & Management (OAM) and compatibility with existing technologies (e.g. spectral compatibility for copper).
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[edit] History
The IEEE 802.3ah working group was established in 2001 in order to enable Ethernet penetration into the Access Networks. In parallel the EFM Alliance (EFMA) was formed by the participating vendors, to promote Ethernet subscriber access technology and support the IEEE standard effort.[1]
The EFM standard was approved on 24 Jun 2004 and published on 07 Sep 2004 as IEEE 802.3ah-2004. In 2005 it was included into the base IEEE 802.3 standard. The EFMA got absorbed by the Metro Ethernet Forum.[2]
Recently, starting in early 2006, work began on a very high-speed 10 Gigabit/second EPON (XEPON or 10-GEPON or ) standard (http://www.ieee802.org/3/av/).
[edit] Details
The EFM defines the following new Ethernet physical layer (PHY) interfaces:
- 2BASE-TL -- defined in clauses 61 and 63. Full-duplex long reach Point-to-Point link over voice-grade copper wiring. 2BASE-TL PHY can deliver a minimum of 2 Mbps over distances of up to 2700 m (9 kft), using ITU-T G.991.2 (G.SHDSL.bis) technology over single copper pair.
- 10PASS-TS -- defined in clauses 61 and 62. Full-duplex short reach Point-to-Point link over voice-grade copper wiring. 10PASS-TS PHY can deliver a minimum of 10 Mbps over distances of up to 750 m (2460 feet), using ITU-T G.993.1 (VDSL) technology over single copper pair.
- 100BASE-LX10 -- defined in clause 58, providing point-to-point 100 Mbps Ethernet links over a pair of single-mode fibers up to at least 10 km.
- 100BASE-BX10 -- defined in clause 58, providing point-to-point 100 Mbps Ethernet links over an individual single-mode fiber up to at least 10 km.
- 1000BASE-LX10 -- defined in clause 59, providing point-to-point 1000 Mbps Ethernet links over a pair of single-mode fibers up to at least 10 km.
- 1000BASE-BX10 -- defined in clause 59, providing point-to-point 1000 Mbps Ethernet links over an individual single-mode fiber up to at least 10 km.
- 1000BASE-PX10 -- defined in clause 60, providing P2MP 1000 Mbps Ethernet links over PONs up to at least 10 km.
- 1000BASE-PX20 -- defined in clause 60, providing P2MP 1000 Mbps Ethernet links over PONs up to at least 20 km.
Additionally clause 57 defines link-level OAM, including discovery, remote fault indication, loopbacks and variable access.
[edit] See also
[edit] References
- ^ Extreme Launches Ethernet Alliance, Light Reading, December 11, 2001
- ^ MEF Absorbs EFMA, Light Reading, March 8, 2005
[edit] External links
- Download IEEE 802.3
- IEEE 802.3ah - Ethernet in the First Mile working group archives
- Ethernet in the First Mile FAQ
- Ethernet OAM whitepaper (pdf).
- EFM Knowledge Base at the UNH-IOL
[edit] Books
- Michael Beck, Ethernet in the First Mile: The IEEE802.3ah EFM Standard, McGraw-Hill Professional, 2005, ISBN 007145506X.
- Wael Diab and Howard Frazier, Ethernet in the First Mile: Access for Everyone, IEEE Standards Press, 2006, ISBN 0738148385.
