NBASE-T

IEEE 802.3bz, NBASE-T and MGBASE-T refer to efforts to produce a standard for Ethernet over twisted pair copper wire at speeds of 2.5 Gbit/s and 5 Gbit/s. This would create intermediate speeds between existing standards Gigabit Ethernet and 10 Gigabit Ethernet. The resulting standards are expected to be named 2.5GBASE-T and 5GBASE-T.[1][2]

IEEE 802.3bz

IEEE 802.3's "2.5G/5GBASE-T Task Force" started working on the 2.5GBASE-T and 5GBASE-T standards in March 2015.[3] Adopted IEEE P802.3bz schedule has a planned approval date of September 2016 for the standards.[4]

The objectives of the task force include:[5]

NBASE-T

The NBASE-T Alliance was founded in 2014 by Aquantia Corporation, Cisco Systems, Freescale Semiconductor and Xilinx.[6] It now consists of more than 45 companies, and aims to have their specification compatible with 802.3bz.[7]

Technology

The physical (PHY) layer transmission technology of NBASE-T is based on 10GBASE-T, but operates at a lower signaling rate. By reducing the original signal rate to \tfrac{1}{4} or \tfrac{1}{2}, the transfer rate drops to 2.5 or 5 Gbit/s, respectively.[8] The Nyquist frequency of the signal is reduced accordingly, lowering the requirements on the cabling, so that 2.5GBASE-T and 5GBASE-T can be deployed at a cable length of 100 m on unshielded Cat.5e and Cat.6 twisted-pair cables, respectively.[9]

Comparison of twisted pair based ethernet technologies

Standard Transfer speed Bits per second
per Hertz 		Nyquist
frequency 		Cable req.
100 m 		Cable spec
10BASE-T 10 Mbit/s 1 10 MHz Cat 3 16 MHz
100BASE-TX 100 Mbit/s 1.6 62.5 MHz Cat 5 100 MHz
1000BASE-T 1000 Mbit/s 16 62.5 MHz Cat 5e 100 MHz
2.5GBASE-T 2500 Mbit/s 25 100 MHz Cat 5e 100 MHz
5GBASE-T 5000 Mbit/s 25 200 MHz Cat 6 250 MHz
10GBASE-T 10000 Mbit/s 25 400 MHz Cat 6A 500 MHz

History

This became relevant around 2014 as it became clear that it would not be possible to run 10GBASE-T over the Cat5e cable that had been used for the wiring in many buildings but that, with the development of fast WiFi protocols such as IEEE 802.11ac, there was a significant demand for cheap uplink faster than 1000BASE-T offered. NBASE-T also supports Power over Ethernet, which has generally not been available at 10GBASE-T.

As early as 2013 the Intel Avoton server processors integrated 2.5 Gbit/s Ethernet ports; in October 2014 the NBASE-T Alliance was founded,[10] initially comprising Cisco, Aquantia, Freescale and Xilinx. By May 2015 [11] it had expanded to 34 members covering most producers of networking hardware. Whilst Broadcom had announced a series of 2.5 Gbit/s transceiver ICs,[12] 2.5 Gbit/s switch hardware was not widely commercially available at that point; 10GBASE-T switches do not generally support the intermediate speeds.

References

  1. ↑ "New IEEE P802.3bz™ Project Achieves Significant Milestone Towards Enabling Higher Speeds Over Installed Base of Twisted Pair Cabling". IEEE Standards Association.
  2. ↑ "IEEE’s 802.3BZ Task Force Mediates MGBASE-T and NBASE-T Alliances". Planetech USA.
  3. ↑ "IEEE 802.3bz Project PAR" (PDF). IEEE 802.3bz Task Force. Retrieved 2015-09-22.
  4. ↑ "IEEE P802.3bz Adopted Schedule" (PDF). IEEE 802.3bz Task Force (Closing Report). Retrieved 2015-11-16.
  5. ↑ "Next Generation Enterprise Access BASE-T PHY Objectives" (PDF). IEEE P802.3bz 2.5G/5GBASE-T Task Force.
  6. ↑ "The NBASE-T Alliance℠". NBASE-T Alliance, Inc. Retrieved 30 December 2015.
  7. ↑ "Oh What a Year!". NBASE-T Alliance, Inc. Retrieved 30 December 2015.
  8. ↑ "Cisco Live BRKCRS-3900, slide 41, time 57:40".
  9. ↑ "Technology". NBASE-T. NBASE-T Alliance. 2015. Retrieved 2015-10-18.
  10. ↑ "Industry Leaders Form NBASE-T Alliance to Promote Multi-Gigabit Ethernet Technology for Enterprise Wired and Wireless Access Networks".
  11. ↑ "NBASE-T Alliance Jumps to 34 Members".
  12. ↑ "Broadcom Announces New High-Performance Multi-Rate Gigabit PHYs".

External links


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