25 Gigabit Ethernet Consortium releases low-latency FEC specification for 50GbE, 100GbE, and 200GbE applications

The 25 Gigabit Ethernet Consortium, a group focused on promoting the use of 25 Gigabit Ethernet and 50 Gigabit Ethernet via standards and overall improvement of Ethernet interfaces, has released a specification for a low-latency forward error correction (FEC) approach. The new FEC regime could be applied to 50, 100, and 200 Gigabit Ethernet networks, the consortium believes.

The 25 Gigabit Ethernet Consortium, a group focused on promoting the use of 25 Gigabit Ethernet and 50 Gigabit Ethernet via standards and overall improvement of Ethernet interfaces, has released a specification for a low-latency forward error correction (FEC) approach. The new FEC regime could be applied to 50, 100, and 200 Gigabit Ethernet networks, the consortium believes.

Latency remains an issue in such applications as high-performance computing (HPC), data center interconnect, machine learning, and financial trading, among others. The new specification enables network equipment manufacturers to use a shortened codeword FEC variant – RS (272, 257+1, 7, 10) – instead of the IEEE 802.3cd and 802.3bs standard FEC. The consortium’s codeword contains 272 x 10-bit symbols rather than the IEEE’s 544 x 10-bit symbols. Use of the new approach will cut FEC latency by approximately 50%, the consortium asserts.

The consortium says it has conducted simulations using the its FEC approach that show support of copper cable lengths of up to 2 m and fiber cable lengths of up to 30 m. However, to ensure high data integrity, the consortium recommends that the shortened codewords only be used on engineered data connections.

“Five years ago, only HPC developers cared about low latency, but today latency sensitivity has come to many more mainstream applications,” commented Rob Stone, technical working group chair of the 25G Ethernet Consortium. “With this new specification, the consortium is improving the single largest source of packet processing latency, which improves the performance that high-speed Ethernet brings to these applications.”

“The value of having a standard extends to ensuring multi-vendor product interoperability and ecosystem,” added Tim Lustig, marketing chair of the 25 Gigabit Ethernet Consortium. “To ensure specification conformance and interoperability, testing will be held at future plugfests the consortium regularly conducts at the University of New Hampshire InterOperability Laboratory (UNH-IOL).”

The specification is available on the consortium’s website. The 25 Gigabit Ethernet Consortium launched in 2014 with Arista Networks (NYSE: ANET), Broadcom Corp. (NASDAQ: BRCM), Google Inc. (NASDAQ: GOOG, GOOGL), Mellanox Technologies, Ltd. (NASDAQ: MLNX), and Microsoft Corp. (NASDAQ: MSFT) as founding members (see “25 Gigabit Ethernet, 50 Gigabit Ethernet targets of industry consortium”). It now has seven “Promoters” members (including the original five) and 40 “Adopters” members.

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