Samiksha Jaiswal (Editor)

Terabit Ethernet

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Terabit Ethernet or TbE is used to describe future speeds of Ethernet above 100 Gbit/s. As of 2015, 400 Gigabit Ethernet and 200 Gigabit Ethernet are under development, using broadly similar technology to 100 Gigabit Ethernet, but 1 Terabit Ethernet is not.

Contents

There's currently no roadmap beyond 400 GbE — “sometime after 2020” — but doubling to 800 GbE is expected to occur when single-lane 100 GbE links become available. This technology might also allow larger lane bundles, possibly providing 1 TbE or 1.6 TbE links with 10 or 16 lanes.

History

Facebook and Google, among other companies, have expressed a need for TbE. While a speed of 400 Gbit/s is achievable with existing technology, 1 Tbit/s (1000 Gbit/s) would require different technology. Accordingly, at the IEEE Industry Connections Higher Speed Ethernet Consensus group meeting in 2012 September, 400 GbE was chosen as the next generation goal. Additional 200GbE objectives were added in January 2016.

The University of California, Santa Barbara (UCSB) attracted help from Agilent Technologies, Google, Intel, Rockwell Collins, and Verizon Communications to help with research into next generation Ethernet.

As of early 2016, chassis/modular based core router platforms from Cisco, Juniper and other major manufacturers support 400 Gbit/s full duplex data rates per slot. One, two and four port 100GbE line cards are presently available, with 200GbE and 400GbE expected to become available after standard ratification.

Development

The IEEE formed the "IEEE 802.3 Industry Connections Ethernet Bandwidth Assessment Ad Hoc", to investigate the business needs for short and long term bandwidth requirements.

IEEE 802.3's "400 Gb/s Ethernet Study Group" started working on the 400 Gbit/s generation standard in March 2013. Results from the study group were published and approved on March 27, 2014. Subsequently, the IEEE 802.3bs Task Force started working to provide physical layer specifications for several link distances. Standards are expected in December 2017.

Project objectives

Like all speeds since 10 Gigabit Ethernet, the standard will support only full-duplex operation. Other objectives include:

  1. Support MAC data rates of 400 Gbit/s and 200 Gbit/s
  2. Preserve the Ethernet frame format utilizing the Ethernet MAC
  3. Preserve minimum and maximum frame size of current Ethernet standard
  4. Define physical layer specifications that support link distances of:
  5. 400 Gbit/s Ethernet
  6. at least 100 m over multi-mode fiber (400GBASE-SR16) using sixteen parallel strands of fiber each at 25 Gbit/s
  7. at least 500 m over single-mode fiber (400GBASE-DR4) using four parallel strands of fiber each at 100 Gbit/s
  8. at least 2 km over single-mode fiber (400GBASE-FR8) using eight parallel wavelengths (CWDM) each at 50 Gbit/s
  9. at least 10 km over single-mode fiber (400GBASE-LR8) using eight parallel wavelengths (CWDM) each at 50 Gbit/s
  10. 200 Gbit/s Ethernet
  11. at least 500m over single-mode fiber (200GBASE-DR4) using four parallel strands of fiber each at 50 Gbit/s
  12. at least 2 km over single-mode fiber (200GBASE-FR4) using four parallel wavelengths (CWDM) each at 50 Gbit/s
  13. at least 10 km over single-mode fiber (200GBASE-LR4) using four parallel wavelengths (CWDM) each at 50 Gbit/s
  14. Support a bit error ratio (BER) of 10−13, which is an improvement over the 10−12 BER that was specified for 10GbE, 40GbE, and 100GbE.
  15. Support for OTN (transport of Ethernet across optical transport networks), and optional support for Energy-Efficient Ethernet (EEE).

References

Terabit Ethernet Wikipedia
(Text) CC BY-SA