Burgess COMMENTARY

The power and speed of computer processing has increased by an amazing amount during my adult life. This plug board was used on a computer I worked with in the 1960s ... and now we talk about switches that operate at speeds of 400 Gbits/second. Though we now have amazing power to compute, there is still a challenge to upgrade human understanding, not so much for the few but for the masses. In this regard, the world has made little progress!
Peter Burgess

Back to ASICs: Mellanox pumps up Ethernet speed to 400Gbps ... 200GbitE and 400GbitE ASIC-powered switches


Mellanox_SN3000_switches Mellanox SN3000 switches

Just as we're getting used to 40Gbps, Ethernet networking kit-flinger Mellanox makes it 10 times faster with a Spectrum-2 ASIC running at up to 400Gbps.

It's doing this because of our old friend incessant data growth. Specific drivers mentioned by Mellanox include AI, real-time analytics, NVMe over fabrics storage array access, hyperscale and cloud data centre needs – all needing increased Ethernet switch bandwidth.

The Spectrum-2 switches programmatically operates at 10, 25, 40, 50, 100, 200 and 400Gbps, making it the most scalable Ethernet switch ever. Mellanox says it has a programmable flexible parser and packet modifier, and supports user-defined protocols. The parser and packet modifier can be programmed to deal with future protocols.

The switch has an on-chip 42MB packet buffer which can be dynamically shared between all ports. Mellanox says it can process 9.52 billion packets per second (pps), which ensures full wire speed at any packet size, down to 64 bytes, and zero packet-loss.

It also says the switch has adaptive routing and load balancing, and guarantees zero packet loss and unconditional port performance. It has telemetry capabilities, including in-band ones, to provide visibility into its operation for network operators.


Spectrum_2_ASIC Mellanox Spectrum-2

We're told Spectrum-2 keeps the existing Spectrum switch API, for porting software onto the ASIC via the Open SDK/SAI API or Linux upstream driver (Switchdev). It supports standard network operating systems and interfaces including Cumulus Linux, SONIC, standard Linux distributions and more.

Spectrum-2 is claimed to have 1.3X lower power consumption and 1.4X lower latency, at 300 nanoseconds, than Broadcom's Tomahawk-2 product.


Mellanox_Spectrum_2_vs_Broadom_Tomahawk_2

Mellanox table comparing Spectrum switches to Broadcom's Tomahawk-2. In the table, * indicates value estimated as double of Tomahawk and ** indicates it defaults to cut through only when all ports are set to the same speed.

The Spectrum-2 technology can provide up to 16 ports of 400GbitE, 32 ports of 200GbitE, 64 ports of 100GbitE and 128 ports of 50GbitE and 25GbitE. Four products have been identified by Mellanox so far:
... SN3700 - 32 x 200GbitE - up to 128x25/50GbtE with cable splitter
... SN3410 - 48 x 25/50GbitE + 8 x 200GbitE - 25/50GbitE -->200GbitE ToR switch
... SN3100 - 16 x 200GbitE
... SN3200 - 16 x 400GbitE

You should be able to get PDF datasheets here. The Spectrum-2 SDK is available now for early-access, and the Spectrum-2 switch ASIC is expected to be available later this year. ®