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32Gb FC is actually 27Gb FC. Yes it’s true.

| October 14, 2017 | Reply

The network technology named “10GbE” means throughput is 10Gb/s, and if you’re like most people, you would naturally believe the network called “32GFC,” means throughput is 32Gb/s. The reality is the name matches the speed for Ethernet, but surprisingly not for Fibre Channel. The speed of the network is significantly less than the names for each generation of Fibre Channel.

If you care to know how many people were aware of this, how we got here, what IT pros think should be done, and what the industry is going to do about it, continue reading.

Who Knew Fibre Channel Names Don’t Match Speed

After talking to several Fibre Channel industry insiders, I discovered it’s common knowledge that actual Fibre Channel speed doesn’t match the number in the name. The next step was to measure awareness of the disparity in the IT community. IT Brand Pulse conducted an independent, non-sponsored survey of 200 IT pros, and not surprisingly, the vast majority expected the name “32GFC” meant the speed of Fibre Channel is 32Gbps.

How This Happened: Speed-Based Naming Is A Baudy Affair

Turns out since the technology was introduced, Fibre Channel went through periods where it was named after its baud rate, followed by the current time frame where Fibre Channel naming is “generation-based.”

After the dial-up modem industry faded away, Fibre Channel alone carried the flag of using baud rate as their reference point for naming. What should be used to identify each new generation of Fibre Channel, is a well established convention: half-duplex throughput in Gb/s. You can arrive at that number by multiplying the baud rate by a factor for encoding overhead. Using Gbaud for naming is, best-case, confusing and somewhat irrelevant. Worst case, it is deceptive. (Watch this video for an explanation of how Ethernet and Fibre Channel performance are measured, and where the GBaud specification fits.)

During the time this 2008 road map was published, the product name was based on the Line rate (Gbaud) specification. However, if you multiply Gbaud x the encoding overhead factor, you arrive at the effective throughput number (and name) which is apples-to apples with Ethernet naming. That means 1Gb FC was actually 850Mb FC, and the technology entered the gigabit age at 2Gb FC, which is actually 1.7Gb FC. Clearly the “Product” specifications in the chart are confusing or deceptive.

Generation-Based Naming

At 8GFC, the naming in the generation-based Fibre Channel road maps was changed to 1GFC, 2GFC, 4GFC, etc. Oddly, the entire SAN industry referred to the technology in terms of Gbps, yet there was no mention of that specification in the speed road map.

The intention isn’t clear with this approach, but the results seem very clear.

  • Result #1: the vast majority of people interpret the names of each generation of Fibre Channel as network throughput, when they are not.
  • Result #2: the market makes the easy translation to throughput (the higher number), and voila!, 16GFC becomes 16Gb FC.
  • Result #3: the industry has plausible deniability, but many customers are misled.

It is common for vendors and industry organizations to drop the Gen 5 / Gen 6 naming convention and misrepresent the technology as 8Gb, 16Gb FC, etc.

It Matters to the IT Community

Next, IT Brand Pulse asked IT professionals what they thought of this dilemma. About two-thirds of the respondents answered, “Not a big deal, but the Fibre Channel industry should update their road map…” However, the industry should take notice that almost a quarter of the respondents think “This is a big deal, we have been deceived for a long time…”

Over 80% of IT professionals surveyed said the FC road map should be fixed.

The Gap is Growing

This was not much of an issue is when the naming logic was “close-enough” at 1Gb FC and the difference between name and speed was .15Gbps. But at 32GFC, the gap is almost 5Gbps, and it’s snow-balling.

On behalf of IT community, I’m calling on the Fibre Channel industry to update their road map so the naming accurately reflects the speed of the network in Gb/s….just like we’re used to with Ethernet. To hold us over until then, IT Brand Pulse has created the Official Fibre Channel Road Map Translator.

As you can see below, we have taken the liberty of renaming each generation and re-introduced “Gb” in the name. By looking at the name, users can easily make an apple-to-apples comparison with Ethernet. I’ve also listed throughput in Gb/s, the well-established convention for network speeds. By using this road map, you will no longer need to convert from MB/s full-duplex to Gb/s half-duplex, in order to get the most widely used specification for network performance.

One of the most interesting data points is that 32GFC is actually 27Gb FC; more of a head-to-head competitor with 25Gb Ethernet than previously thought.

In Industry Organizations We Trust

The networking industry is a highly-competitive arena with tens of billions of dollars on the table. In spite of the high stakes and intense competition, the industry organizations that document standards and specifications have earned our trust by publishing accurate information about Fibre Channel, Ethernet and InfiniBand. Traditionally, it’s been left to vendor product marketing teams to add spin to the basic specifications in the industry road maps

A shout-out to the Fibre Channel industry to take a serious look at this. If not, we look forward to getting lots of views on the Official Fibre Channel Road Map Translatorin the months and years ahead!

Category: Articles by TFC

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