Benefits that Mesh Well TogetherWireless mesh networks are taking on an increasingly important role in the security industry. And they’re doing so for good reason. The deployment of mesh networks can ensure users gain greater levels of reliability, flexibility and reduced costs, while at the same time enjoying superior network coverage.
A wireless mesh network is one in which all devices that are part of a network have multiple links to communicate with each other, explains Cosimo Malesci, vice president of sales for Boston-based Fluidmesh Networks, a manufacturer of point-to-point, point-to-multipoint and mesh networks for security and industrial applications. “This solution’s advantage is that you do not have a single point of failure in the network,” he says.
Wireless mesh networks are organized collections of intelligent multi-service, modular, multi-radio wireless access points, more commonly called “wireless mesh nodes,” capable of automatically establishing and maintaining multiple relationships and connectivity between nodes in the network, explains Kirby Russell.
Russell is director of sales and marketing for Strix Systems in Calabasas, Calif., which focuses on wireless service solutions for indoor and outdoor applications. The nodes in the network form high-speed backhaul, while simultaneously providing high-performance user access across the network, whether stationary or mobile.
“Each node has multiple radios,” Russell explains. “The nodes can create the mesh network by themselves. They scan the air and find other mesh network nodes that need to be incorporated into the network, and build the network in milliseconds.”
Once the relationship is established, it allows laptops with browsers connected to the Internet, or the video surveillance cameras wirelessly connected to the network or direct-connected into a node, to ride on top of the network, Russell says. This is referred to as a Layer-2 network, the highest performance wireless mesh network that can be created to support the transport of video, data and voice over IP (VoIP).
Alarm signal communications is another function of a mesh network. “Imagine having seven or eight phone lines in your house, or seven or eight cell towers. It is not feasible or practical,” said Michael Sherman, president and CEO of AES Corp., Peabody, Mass., the maker of the AES-IntelliNet long-range mesh alarm communications system. According to Sherman, “A mesh network is like having seven or eight unique routes or paths to get your signal through to the central monitoring station, unlike single path failures so evident with phone line or IP dependency. It’s a unique communications network in which all points of communication act as a receiver, transmitter and repeater of alarm data so the signal will always be delivered without fear of power failure, line cuts or downed towers, etc. It all but eliminates the monthly costs and gives the user total independent control over the communications network without requiring any radio expertise since the network self-adjusts to changing conditions.”
One of the key objectives of mesh networks is reducing wired sites, says Chip Yager, director of operations for Motorola Inc.’s mesh network product group.
“You’re providing all this access to data, over a wider area, but with fewer wired data points,” he says. “You’ve not only reduced monthly costs for every one of those wired connections that you now avoid, you’ve provided much better network coverage.”
To understand that superior coverage, consider a typical cellular telephone or radio system featuring sky-high antennas, Yager says. In such a so-called “high-site system,” users are able to receive signals as far as the antennas are capable of sending them. But if users walk behind a large building, they may not be able to receive the signal, he points out.
A mesh network, by contrast, is a “low-site system” that uses more access points. Those access points are deployed perhaps just 20 feet off the ground on light poles or the sides of buildings, and transmit just an eighth or a quarter of a mile.
“But there are lots of them, so you’re much more apt to be within coverage range,” Yager reports. “Not only that, but you’re going to very likely be much closer to each access point, which can improve data speeds.”
DIFFERENTIATING MESHThe best way to position “wireless mesh” is to contrast it with other available wireless technologies, explains Ksenia Coffman, marketing manager for wireless mesh network provider Firetide, of Los Gatos, Calif. “If you look at the available wireless technologies, you can see wireless mesh is clearly differentiated,” she observes.
Point-to-point wireless systems. These systems provide connections between two fixed locations, and often offer greater capacities and distances compared with point-to-multipoint and mesh technologies. These connections, or bridges, are ideal for backhaul of other wireless technologies, Coffman explains.
Point-to-multipoint wireless systems. These systems deliver high-speed network connections to multiple remote locations. When towers or tall buildings are available, point-to-multipoint systems can offer cost-effective deployments. However, the central “base unit” creates a potential single point of failure.
“Should the unit lose power or become inoperative, the whole network goes down,” Coffman says.
Multipoint-to-multipoint (or wireless mesh) systems. These systems are by their very nature self-healing for resiliency, Coffman notes. Redundant links eliminate single points of failure associated with conventional wireless networks, while multiple paths overcome line-of-sight issues. On a wireless mesh network, unlike with a point-to-multipoint system, any mesh node can act as a “head end,” allowing multiple command centers to be set up, at any point in the network, she describes.
The flexibility of mesh allows it to be deployed in any of the above scenarios â€” point-to-point for backhaul, point-to-multipoint, or “true” mesh for complete redundancy.
Some deployments start as point-to-multipoint, later to be reconfigured into a mesh topology, when security needs call for ubiquitous coverage, Coffman says.
RELIABLE & FLEXIBLEMesh technology is used in security to provide a wireless infrastructure with a higher level of reliability than that offered by traditional wireless solutions, Malesci says.
That enhanced reliability flows from the fact that all devices that are part of a mesh network automatically find the optimal path to send data to the head end. “This type of network clearly makes the whole system more reliable,” he adds. “For this reason, it’s a good fit for the security industry, where reliability is a big concern.”
It’s surprising, but true nonetheless, that a wireless mesh solution can often be more reliable than a wired solution, states Stephen Rayment, chief technology officer for BelAir Networks, a Kanata, Ontario, provider of broadband wireless network infrastructure equipment since 2002. Because it’s a mesh network, there are multiple paths to return to a wired egress point in the network. If a link to the camera at Node A fails, that node has the intelligence to automatically reconnect to Node B, Rayment says.
“So you have this inherent redundancy in wireless mesh networks,” he adds. “With a wireless point-to-point connection, by contrast, you don’t have this redundancy. If that link fails, it’s similar to someone cutting the wire. But with a wireless mesh network, the built-in redundancy gives you that extra level of security.”
This dependability is another benefit of a low-site, as opposed to a high-site system, Yager says. If lightning strikes an antenna on a high-site system, it’s likely the entire system will go down. With the low-site system of a wireless mesh network, any one access point makes up just a small percentage of overall coverage. The network is designed to heal itself, to find multiple routes to get data from one site to the next.
“The result is a high-capacity, dense coverage network that can support a wide range of applications, throughout a city or a business facility,” he says.
“With other technologies if a strong wind blows during a hurricane or a tornado, or if an ice storm occurs, they lose electricity, or a cell tower goes down â€” then everyone depending on that electricity or that cell tower is vulnerable. But with a mesh network, that is never the case, because there are seven or eight paths that are always up and running,” says Dee Frazier, marketing communications manager for AES Corp. “To me, a mesh network means that no matter what Mother Nature throws at you, you are protected and that’s real reliability.”
Mesh networks also offer flexible reconfiguration, Rayment describes. In mesh network technology, radio nodes communicate wirelessly with each other to create a fully interconnected network solution, he says. “It gives you real flexibility. All the nodes are talking to all the other nodes, so it allows you to add nodes to the network, or delete nodes from the network. It’s very easy to reconfigure. That reconfiguration means you can easily service rapidly changing environments.”
For example, in an emergency situation, it is infeasible to install wired circuits. In the case of a special event, a circuit might have to be leased for a few weeks or a month. With wireless mesh networks, such steps are unnecessary, Rayment says.
Clearly, mesh networks can yield cost savings. The connection of a number of CCTV cameras is a common security application. But installing wires to many CCTV cameras is very costly. Using a mesh network to provide this kind of interconnectivity is more economical. There is no need to trench, or lease circuits from service providers.
“There are cost benefits and time-to-install benefits,” Rayment says. “These things usually go in in a couple of days, a wired installation a couple months.”
TWO PRIME APPLICATIONSThere exist two distinct applications for mesh networks. In one, they are used for alarm signal transmission from a security system to a central station. In another, they are employed for video or data transmission from a camera to a remote location where the surveillance is being monitored and/or recorded. Both use mesh technology as the architecture behind the network, but there is a crucial difference between a mesh network for alarm or fire and a mesh network for video and data, Malesci reports.
That difference is the radio frequency they use to transmit. An alarm or fire application requires low bandwidth and very long-range transmission. Consequently, such applications use low radio frequencies, such as UHF or VHF frequencies.
On the other hand, a network for video application necessitates considerable bandwidth, and tends to be limited to substantially shorter ranges. As a result, higher radio frequencies, such as 2.4 GHz or 5.8 GHz, are utilized, Malesci says.
These video/data networks also can be used for access control, emergency phones, voice over IP systems, intercom and WIFI coverage, he adds.
Within the realm of video and data transmission, there is another choice, as well, and that is fixed or mobile applications. “We see interest in both,” Rayment relates.
“You might have, for example, a video camera in a moving emergency response vehicle. As the officer approaches the scene of the incident, he can be sending real-time full-motion video images back to headquarters, to give officials a sense of the scope of the incident. That’s an example of a mobile application.”
Another situation where mobility is in play is one in which a law enforcement officer equipped with a laptop computer and a wireless connection in his cruiser can access images from the scene of the emergency as he speeds to that scene, Rayment says. Or he might be able to view an image sent by headquarters of the floor plan of the building being impacted by the emergency, allowing him to be fully prepared to enter once he reaches the scene of the quickly unfolding incident.
THE IMPACT OF IPMesh networks are IP-based, and are IP networks in every sense of the term.
“The advantage of having an IP technology together with a mesh network is that you have the freedom of actually integrating your mesh network with any type of IP product available,” Malesci says. “First, that means non-manufacturer specific products. And secondly, it means you can change the types of devices. You’re not limited to an IP camera. You can go with an IP encoder, or a voice over IP phone, for example.”
Because it’s not limited to video and can integrate any type of IP device, the benefit is a higher return on investment when the network is deployed, Malesci adds.
Almost all modern CCTV cameras are now digital and IP-based, Rayment says. That leads to another advantage of mesh networks using IP technology. Highly sophisticated processing, including video storage and video analytics, can be undertaken on the images being communicated over mesh networks, and it can be done in real time right over the mesh network.
“When a wireless mesh network includes IP technology, such as with AES-IntelliNet’s MultiNet long-range wireless mesh alarm communications system, it allows dealers and central stations the ability to grow their businesses endlessly. Now by deploying an IP link, a dealer in New York can expand their network cloud, or create a new cloud in New Jersey or a central station in California can monitor radios in Chicago,” Frazier says.
SIDEBAR: Real World ApplicationsWhere are wireless mesh networks in operation? To name just a few settings, in the police departments of Dallas, Denver, St. Paul, Buffalo and Phoenix; in the Sheriff’s Department of Los Angeles County and in Chicago’s Office of Emergency Management and Communications, all of which use Firetide mesh networks.
Mesh networks also are in use on the North County Transit District of San Diego, where data telemetry and video surveillance capabilities were first brought aboard, and efforts are now underway to add passenger use of Internet and VoIP as well. Both are provided by Strix Systems. In Pittsburg, Calif., a wireless mesh network from Strix Systems connects 50 cameras deployed in higher crime areas. And in Brookline, Mass., Strix Systems gave residents border-to-border municipal WIFI through the deployment of a wireless mesh network that also allows officers in police cruisers to connect to video surveillance cameras and to data from police headquarters.
SIDEBAR: To Consider When Selecting a SolutionMany wireless mesh network solutions exist in the marketplace, says Cosimo Malesci. It’s important that security professionals select a mesh manufacturer that is optimized for video applications, he believes.
“Video is important to the security industry, and from a technical standpoint, sending video across a wireless network overall is very different from sending general data â€” and much more sophisticated,” he says. “Best to select a wireless manufacturer that has experience with security applications, and is optimized for video.”
“For applications such as security and fire alarm reporting, however, a mesh network solution optimized towards data only (as opposed to video) will typically be the more cost effective and farther reaching across a region,” Sherman adds.
SIDEBAR: Mesh Networks for Access ControlIn the world of access control, the biggest impediment to running systems on networks is the control equipment required, says Steve Pineau, CEO of Vancouver, British Columbia-based Viscount Systems. Viscount Systems was established in 1969 as a research and development division of one of Canada’s largest telephone companies, and subsequently evolved into a manufacturer of telephone-based intercom systems. Today, Viscount makes IP-based access control systems.
“Control equipment has always been of a proprietary nature,” Pineau says. “So we write software for intelligent devices â€” like reader devices â€” that can directly connect to the networks without use of the old control panels,” he explains.
Newer readers can be run across wireless mesh networks as well as LAN networks, Pineau adds. When the reader is “tagged,” a message goes from the reader through the wireless mesh network to a remote server. The server makes a decision, sends the message back through the wireless mesh network to the reader, and the reader has the intelligence to unlock the gate or door, Pineau says.
“You can’t do that with traditional equipment,” he adds. “Traditional systems require an awful lot of hardware. The key to being able to run access control over a network is both having servers with the power to run large numbers of readers, and having readers that possess the intelligence to open the doors and control other devices at the door, such as exit devices, infrared detectors and others.”
One concern security dealers and installers might voice is with bandwidth, but that’s not really an issue, Pineau adds. Unlike video, bandwidth necessary to run access control is negligible. “If you have a lot of video running across the network, it chews up your bandwidth,” he says. “With access control, there’s no impact.”