Monday, December 9, 2013

A Cautionary Rant about "Aggregate Throughput"

I cringe when I hear, "aggregate bandwidth" or "aggregate throughput" as it's commonly used by radio marketeers. To me it's madly misleading, and so I take offense when a salesperson uses it on me, though I know they're just following convention.

By "aggregate" throughput, the vendor is taking the transmission rates (potential) from both directions and adding them together. It's as though someone asks you how much you can bench press and you say 300 pounds because you can lift 150 pounds up and then back down. Or that you can jump six feet because in your three foot leap, you come down three as well.

I've been selling bandwidth since leaving college in the 80's, and since the first Ethernet radios (FCC licensed) made it on the market, speeds have always been quoted as full-duplex, the assumption being that you're getting the same performance from the other end as well. Isn't that the way you order phone lines or fiber?

But 802.11 radios at 2.4 GHz (and later 5.x GHz) were quite slower than FCC licensed ones, largely owing to all the software overhead, and after they made the scene some marketing genius decided that 24 Mbps didn't sound "robust" enough and so he called it a 48 Mbps "aggregate" rate. I wish that all other vendors had declined to follow suit, but they caved because no one wants to appear to have a slower product.

All the while, FCC licensed radios (true "carrier-class" radios), have continued to quote the actual full-duplex data rate (since the 1980's) and I hope that never changes. The main buyers of those radios are sophisticated telecom operations - along with larger enterprise users, and they wouldn't put up with crazy-ass throughput representations. Nor, now should you.

As a PS: "Aggregate bandwidth" is of course not the same as when you take feeds from multiple radios (or fiber, etc.) and combine them in your switch. That way of talking about "aggregate" throughput makes all the sense in the world. 

#aggregatebandwidth #microwavebandwidth #rfbandwidth #wirelessthroughput #wirelesswan 

Wednesday, November 27, 2013

Dumb Things Some “Consultants” Say about Microwave

I’ve heard them all. That microwave goes out in rain, or is bothered by snow, or that it’s bad in fog or even that you’ve got to worry about bird migrations. Then there’s the solar flares!

Never believe a blanket statement about microwave because “radios” come in a wide frequency range from 2 GHz to 80 GHz, and the radios behind those signals use a variety of different type antennas. Your microwave link might have a one degree beam or a thirty degree beam. Different frequencies and different antennas have a huge bearing on how the signal acts, whether in rain or shooting over ten miles of ocean.

Point-to-Point, 6GHz, Microwave WAN Connection
  A 69-Mile, 6 GHz "radio" w/8' dishes running 400 Mbps, full-duplex (redundant)  

Generally, lower frequency radios go further distances and so we have a 6 GHz link that goes 69-miles. At the other end of the spectrum, a 60 GHz link is hardly useable beyond ¾ of a mile, depending on your rain region. Yes, rain effects 60 GHz radios, but if you go to 6 GHz, you’ll never have a rain problem.

Whether a microwave link holds up to the elements is entirely a matter of proper frequency selection and transmit power, the right antenna type and size, and a good installation. These are all things your microwave integrator is supposed to handle because in the end, it’s their responsibility. They’re on the hook for performance, not the microwave manufacturer, who won’t come out to the field to fix these problems or reimburse you for an ill-fated purchase.

Sunday, November 24, 2013

You're the Future for Microwave Makers as Telco Biz Dries Up

If you're an IT manager - in health care, education, business, etc., then you've probably never heard of the major microwave manufacturers. That's because they haven't paid much attention to you, because it's telco and government orders that got them listed on Wall Street, not end user business, which has been a relatively insignificant part. But times are changing. Telco business will dry up for microwave, the way the cable broadcase industry did in the late 80's.

Nothing convinced me of this more, as when I tried to sell Comcast on a 6-8 gig microwave backup - which was everything we could deliver based on frequency availability, and they said that it would hardly cover them. Just last year they thought that same connection would be great at 4-gigs. It was a revelation to me, that a sea change is coming for manufacturers who've depended on carriers as a mainstay. Fiber bandwidth is easy to grow if you just keep lighting more strands of it, but microwave is limited according to available frequencies and channel bandwidths, and telco appetites are outpacing the technology. 

Microwave will always be a great option for enterprise applications, but manufacturers will have to do more to get the word out. Despite its inherent value and tremendous reliability, microwave is still a niche solution and it's all for lack of market awareness. But expect to hear more about microwave as makers look for enterprise business to fill the void left by telco. 

Meanwhile, buyer beware, because you're more dependent on your microwave reseller/integrator than you think. If they botch your path engineering or installation, or aren't good on support, then there's little the manufacturer can or will do for you.