In recent weeks, Cisco Systems has unveiled what it described as the first "intelligent wireless mesh solution" that will make it easier for municipalities to provide high-speed wireless network and Internet connectivity services.
The solution uses the new Cisco Aironet 1500 Series access points (APs) specifically built for large-scale deployments. These utilize two radios for maximum data integrity and throughput. This means that unlike many other Wi-Fi access point systems, the Aironet Series 1500 operates effectively without a direct connection to a wired network at every access point.
Requiring a direct connection to a wired network has been one limiting factor for wide area Wi-Fi deployments. But wireless mesh networks need far fewer access points with wired connections. Mesh access points can use their wireless capabilities to transmit backhaul traffic from one access point to another and out to the Internet over the most efficient path.
Part of the Aironet Series 1500's efficiency lies in its two-radio approach. With one radio dedicated to backhaul (direct AP-to-AP communications), the other radio in Aironet Series 1500 is free to use all available data channels for access while minimizing the chances of RF interference. Additionally, the dual-radio design means that access points can segment the wireless network for different types of users, such as for police, fire, or municipal services who can then securely tie back into their existing indoor network.
For HarborLink Network, LLC, a wireless LAN solution provider based in Dayton, Ohio, this was the solution the company was looking for to expand its business of deploying single-site wireless public access hotspots across the U.S. to deploying large-scale mesh networks. HarborLink was involved in field trials of the new equipment, installing it in a square mile area in Dayton.
"When we first looking at MESH networks, we looked at a number of manufacturers," explained Travis Tangeman, vice-president and chief technology officer at HarborLink. "The stipulation from our office was that the backhaul had to be on 5 GHz because the 2.4 band is so dirty and used by so many devices. Currently, for instance, in downtown Dayton, we are tracking 150 rogue access points that are in the 2.4 frequency. Those are generating quite a bit of interference. But add into that cordless phones, baby monitors and microwave ovens, there is a lot of interference on 2.4. To lose the backhaul because of interference is just unacceptable. So looking at it from a service delivery perspective, although 5GHz is not completely safe, it is much better and much more robust than 2.4."
HarborLink, in a public-private partnership with the city of Dayton, deployed the one-square mile Wi-Fi access zone that gives citizens and businesses free Internet access. And the success of this has now led Dayton to plan coverage for the entire city, 55 square miles, by the end of 2006.
"Ubiquitous access to the Internet is what drove the city of Dayton to consider wireless mesh technologies," said William E. Hill, director, Information and Technology Services for the city of Dayton. "By working with HarborLink, we have created a public-private partnership that is ushering in a new era of free Internet access for all."
Ease of Deployment
Tangeman emphasized that any technology they used needed to be inexpensive to deploy and easy to control from HarborLink's Dayton headquarters. The Cisco system, he said, met all these criteria and more.
"For one thing, this solution is very easy to install as the 'brains' of this architecture is
in a controller unit back in your rack," Tangeman said. "This means that when you deploy radios, you are simply deploying a device that gets plugged into power. It is a simple as driving a bucket truck under an outdoor lamp post, attaching the radio to the arm and plugging it into power. Then it self adds itself into the network and actually joins the mesh from there. So you don't have to take time to set up each individual access point. It's 20 minutes verses hours to install each access point."
Tangeman added that it is also very easy to manage the whole network because everything is controlled from a central location. "You are looking at one screen to manage one or even multiple networks," he said. "We currently track two cities, a college campus and some private networks all from one screen. We know what's happening on each one of those and can see any potential issues that might be occurring on any one of those all from the one screen. So it is very simple, very user friendly and very robust. And you can do things like drilling down to the individual access point or the individual client to find out exactly what is going on there. But you can also do things globally. So if there is a massive change you want to make, you can do it with the click of a button."
The Cisco two-radio access points which HarborLink is deploying in Dayton.
Intelligent System
The heart of Cisco's new system is what the company calls the Cisco Adaptive Wireless Path Protocol that provides the key intelligence for effectively running the Cisco mesh networks. The Aironet 1500 Series access points use sophisticated mathematical algorithms to decide the best ways to route traffic from access point to access point and then out to the main wired network.
"The protocol helps traffic avoid congested nodes, offering the wireless networks a 'self-healing' capability," explained Ben Gibson, director of wireless and mobility marketing for Cisco. "And the wireless LAN controller provides centralized management and real time dynamic FR management, meaning it is managing the air that the access point is serving to ensure that there is maximum network up-time. The network automatically reacts to any issues. Let's say you have some interference issues around one access point. The controller system recognizes that and adjusts output power on adjacent access points to be able to cover or to provide even greater coverage to compensate for an access point that may be having issues due to interference, down time or what have you."
"Really, what I'm talking about here is very much akin to a cellular network approach in terms of using outdoor Wi-Fi," Gibson added. "In other words, the network is not only self-healing in terms of its mesh interconnectivity -- and there is a lot of talk about that -- but probably more important, it is self healing in terms of the access layer, providing access to the customers."
Gibson also believes that the ease of deploying a network is vital to help municipalities undertake Wi-Fi mesh projects. "As part of the system, you can enter in an outdoor map of an area. Using that you can plan very easily where access points have to be deployed to be able to provide contiguous coverage. And then you can also do all the channel mapping exercises on the map. A lot of issues that used to have to be done manually are simply built into the central control system. That's what we mean by intelligent Wi-Fi mesh."
"Our approach to this market was that conventional Wi-Fi just ruggadized for outdoors wasn't nearly enough to
meet the market demand for this space," Gibson added. "It needs to be easier to deploy and then it needs to have real time adjustments for network management when operating."
In actually using the system, the management capabilities are what continue to impress Tangeman. "Essentially, if we get a phone call from a customer who is experiencing problems, instead of going through a guessing process, using the location piece that comes with the system, we are actually able to look on a map, figure out where that user is. And we find all the details regarding that client -- their signal level, what state their wireless card is in, if it is being heard at all, do they have an IP address statically assigned, a proxy turned on -- all these different things plus the routing of their signal through other access points. We can do so many things with just a click of a button instead of guessing at it blind. That makes continuing network administration easy."
Based on their practical experience using the system, HarborLink is now moving forward full-bore into the Wi-Fi mesh deployment business. Not only do they plan on bidding to install and run Dayton's expanded citywide network, but they also have discussions underway with half a dozen other municipalities to deploy similar networks there. "In my view, out of the box, the Cisco solution was simply light years ahead of all the other solutions we looked at," Tangeman said. "It certainly was what we were looking for here."
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