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Comment by aomix | Hacker News Reader

That number seems stupendous but I don't know enough to know that. My very casual understanding was that 100G was state of the art.

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100G is not quite state-of-the-art anymore, but it is what is being deployed. This chip supports 10G ports, and can do 400Gbps through it, but does not support 100Gbps front-panel ports from what I can see.

There are field trials and pre-prod switch/route chips and optical/DWDM gear that support 400G Ethernet using 56Gbps SerDes. This chip uses older 12.5Gbps SerDes, current-gen 100Gbps stuff uses 28Gbps SerDes.

100G has been around for a while and not that common in usage, other than extreme cases. 10g and 40G are still the most widely used ports. Considering that most switches and routers have a minimum 10-20 ports (10g-40g), that's already a stupendous amount of BW - and on routers, you can always add more cards. 100g routers/switches are very expensive.

Unless you are pushing google/facebook/Comcast level traffic - there are very few use cases. Apparently, Google/Facebook uses their own network hardware.

This isn't really true in the market today. 100G switches have emerged at roughly the same cost per port as 40G from a couple of years ago and, indeed, can often accept both 40 and 100 gig optics. Even at list price the cost per port for 100G switching has been under $1K for more than a year.

As a result it's actually fairly common to find new DC fabrics (read: inter-switch connections, not end hosts) being built with 100G because there's no significant economic disadvantage to doing so. That said, the pricing for inter-site 100G is still high enough that it hasn't commonly made its way to smaller organizations.

Google, Apple and Facebook also use commercial network products for the points in there networks where they need to go fast, just like everyone else.

> My very casual understanding was that 100G was state of the art.

I think you're having the same conceptual issue that I had when first reading it.

The 400G in the article title is referring to the bandwidth of the chip, not the bandwidth of any particular port.

The ports, as mentioned elsewhere here, were probably either 10G or perhaps 40G.

It is. Any links higher than that are pretty much all Nx100G, though there are a few carriers with (limited) 200G waves in production.

For anything over 100G (currently) you're making some sacrifices on distance and may even need some guard bands.

(Short-haul/intra-DC may well be a different story but I doubt that it's very different.)

True for routing. For optical 200Gbps DP-16QAM is commercially available.

In the DC 100g is pretty common now.

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