Terabit Ethernet (TbE) is Ethernet with speeds above 100 Gigabit Ethernet. The 400 Gigabit Ethernet (400G, 400GbE) and 200 Gigabit Ethernet (200G, 200GbE) standard developed by the IEEE P802.3bs Task Force using broadly similar technology to 100 Gigabit Ethernet was approved on December 6, 2017. On February 16, 2024 the 800 Gigabit Ethernet (800G, 800GbE) standard developed by the IEEE P802.3df Task Force was approved. The Optical Internetworking Forum (OIF) has already announced five new projects at 112 Gbit/s which would also make 4th generation (single-lane) 100 GbE links possible. The IEEE P802.3df Task Force started work in January 2022 to standardize 800 Gbit/s and 1.6 Tbit/s Ethernet. In November 2022 the IEEE 802.3df project objectives were split in two, with 1.6T and 200G/lane work being moved to the new IEEE 802.3dj project. The timeline for the 802.3dj project indicates completion in July 2026.

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 September 2012, 400 GbE was chosen as the next generation goal. Additional 200 GbE 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 100 GbE and one port 400 GbE line cards are presently available. As of early 2019, 200 GbE line cards became available after 802.3cd standard ratification. In 2020 the Ethernet Technology Consortium announced a specification for 800 Gigabit Ethernet. 200G Ethernet uses PAM4 signaling which allows 2 bits to be transmitted per clock cycle, but at a higher implementation cost. Cisco introduced an 800G Ethernet switch in 2022. In 2024, Nokia routers with 800G Ethernet were deployed.

Standards 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. The IEEE 802.3bs standard was approved on December 6, 2017. The IEEE 802.3cd standard was approved on December 5, 2018. The IEEE 802.3cn standard was approved on December 20, 2019. The IEEE 802.3cm standard was approved on January 30, 2020. The IEEE 802.3cu standard was approved on February 11, 2021. The IEEE 802.3ck and 802.3db standards were approved on September 21, 2022. In November 2022 the IEEE 802.3df project objectives were split in two, with 1.6T and 200G/lane work being moved to the new IEEE 802.3dj project The IEEE 802.3df standard was approved on February 16, 2024.

IEEE project objectives

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

802.3bs project

Define physical layer specifications supporting:

802.3cd project

802.3ck project

802.3cm project

802.3cn project

802.3cu project

802.3cw project

802.3db project

'IEEE P802.3db 100 Gb/s, 200 Gb/s, and 400 Gb/s Short Reach Fiber Task Force'

802.3df project

IEEE P802.3df Objectives for 800 Gbit/s Ethernet and 400G and 800G PHYs using 100 Gbit/s lanes

802.3dj project

200G port types

400G port types

800G port types

1.6T port types