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Wired Networks Face Limited Future: Page 2 of 3

So in any case, $1 million in cable savings and switch port savings right out of the gate, and we were able to put in the 300 devices in 60 days. They were looking at rolling 500 a quarter. We did the 300 in two months. So in the span of July/August, before the school year started, the network goes in, up, running. So how do you calculate ROI? Well, the million-dollar savings is a given, and there's the fact that you had an operational network in two months instead of 12. All the students had advantage of the network for the full school year.

InformationWeek: And the reason that it would have been delayed was because of union cable drops or just because between IT's labor and contractors' labor, that was sort of the work capacity that they had. Why?

Gates: They just figured that they could put 500 access points up per quarter. So whatever that boils down to--125 or 130 a month.

So you figure they're hanging up six access points a day. They're pulling a cable, putting in an access point. So when you look at that, 2,000 devices will take them a year. Three hundred devices, two months. Huge.

When you take a look at deploying very scalable, high-capacity wireless networks that can handle that sort of device count, this becomes a much more economical way to do it.

Interestingly enough, at CMU, when we installed the network, that first fall when the kids came in, there are 5,000 undergraduate students at the school and probably 4,000 in the dorms, and there were 4,000 unique MAC addresses. Makes sense. Beginning of the school year this year: 7,000. I went and visited just a couple weeks ago: 13,000. That's an iPad, a phone, and in the dorms, gaming consoles, printers.

InformationWeek: No wonder we need IPv6, right?

Gates: That's been our biggest challenge. They had planned their DHCP pools to handle one address per student. Beginning of the school year we got a frantic call: The wireless network isn't working. So we sent our guy out on site. We helped them reconfigure their DHCP pool to be larger. That's when they discovered they had twice as many wireless devices [as they'd expected]. And so now they're aware of it, and they're thinking about larger pools. But the average is now three devices per student.

Another interesting thing they did: Beginning of this school year, they turned off all of the Ethernet ports in the dorms. They noticed that they weren't being used anyway. Just shut them all down. And you now have to go to the IT help desk and fill out a port-activation form [to get a wired port] and I think the number's less than 100. So students that absolutely want to be on the wire have to fill out a port activation. But less than 100 of those 4,000 students have.

InformationWeek: And how's that benefiting CMU?

Gates: First of all, they don't have to manage them. And in many cases they've just turned the switches off.

InformationWeek: And maybe they can recoup some of those switches, reuse them. Is that the idea?

Gates: That or eventually they're going to decommission them and not have to pay maintenance on them.

InformationWeek: That's a really great example. Do you have another industry or enterprise example?

Gates: Port of Houston is a good example. Port of Houston, government agency, wanted to use Wi-Fi in the docks. And they were looking at hanging I don't know how many hundreds of Cisco APs on all these light poles around the dock to be able to provide the Wi-Fi coverage, and then figuring out how to backhaul all of them. We were able to cover the entire port with 40 devices. They're hanging up on the light poles. They're about 100 feet in the air. We have enough radios in each device that [they could use] a couple of the radios for wireless backhaul between the arrays.

So out of those 40 devices, less than 10 have got a fiber backhaul into their network. The rest of them are connected with these wireless distribution connections, array to array. So we have less than 10 fiber links and only 40 devices hung, we got pervasive Wi-Fi coverage on the entire dock. This would have been hundreds of access points--and very likely every single one of them needing backhaul to make that work.

In the manufacturing scenario as well, because of the long range of the device, we covered a much larger area, whereas to hang individual access points I would need to put closets in the middle of the floor. I've only got 100 meters from any one direction, and so building an IDF [intermediate distribution frame] from the middle of the floor is not an attractive solution. [We enabled them to] eliminate that and cover the entire space with fewer devices and fewer poles.