Marvell Semiconductor is off and running with 802.3cd-compliant chips, and reckons it's the first sand-baker to ship to the standard.

The IEEE's 802.3cd standard defines the physical ports for current and future high-speed Ethernet interfaces – the 50 Gbps, 200 Gbps and 400 Gbps rates expected over time to replace 25 Gbps and 100 Gbps.

Marvell's Alaska C 88X7120 transceivers, sampling now, support 16 50 Gbps ports, four 200 Gbps ports, and two 400 Gbps ports, using PAM4 signalling. They're aimed at top-of-rack switches with interfaces from 25 Gbps to 100 Gbps, and 200/400 Gbps Ethernet line cards.

PAM4 is a four-level pulse-amplitude modulation technique designed to replace the non-return to zero (NRZ) binary modulation. The IEEE has a comparison of the modulation schemes in this document (PDF) from 2004.

So customers don't have to call in the forklift, the devices support translation between the two modulation types (referred to as “gearboxing”), for compatibility with existing optics and I/O.

Marvell says the 88X7120's port density is optimised for two port types: QSFP-DD (Quad Small Form Factor Pluggable – Double Density) and OSFP (Octal Small Form Factor Pluggable).

The QSFP-DD spec was first published in 2016 and had its third release [PDF] in September 2017.

OSFP is an eight-lane port spec designed to cope with the high power dissipation needed for 400 Gbps operation.

The chips also support long-reach serialisation/deserialisation (SerDes) on “system and line side interfaces”, the company's announcement stated, so OEMs can use the chips for wide area interfaces.

There's a product brief for the C 88X7120 in this PDF.

Buyers can expect to see OEM products landing in 2019. ®