This whitepaper seeks to educate and explain the benefits of a wireless IP based access control system.
By AvaLAN Wireless Systems
Over the past several years, much attention has been paid to the development and deployment of IP-based video surveillance systems. However, the rate of adoption of these exciting new technologies has been slowed in part by the heavy bandwidth consumption of video streams, and their resulting adverse impact on the network. Meanwhile, unhindered by these restraints, manufacturers of (relatively low data-rate) access control systems have been gradually introducing network-based offerings of their own. The idea of course is to take advantage of the powerful and ubiquitous TCP/IP communication platform, without the drawback of negotiating to convince the IT department to allow you to consume large quantities of their most precious commodity: bandwidth.
Furthermore, the IP network is relatively affordable to deploy and universally understood; IT professionals from any nation of the world all work within the same framework and rule set, therefore installation and configuration challenges associated with proprietary technologies are all but eliminated.However, in many cases, a wire-line network connection is not readily available at all of the locations where access control points may be required in the facility. Very few buildings – even those constructed in the modern era – include network connections (RJ-45 ports) at their doors and gates. As a result, wireless technologies are increasingly being considered to deploy these Ethernet-based edge devices. This three-part series explores the factors to consider when designing and deploying a wireless Ethernet-based access control system.
Technology Overview & The Business Case for Wireless Ethernet Solutions:
• Why Select Ethernet vs. Other Transport Protocols?
• Why Choose Wireless for Ethernet Transmission?
Traditional (non-Ethernet) Protocols
With its introduction several decades ago, electronic access control has solved many of the limitations of mechanical locks and keys. A wide range of credentials can be used to replace mechanical keys. The electronic access control system grants access based on the credential presented. When access is granted, the door is unlocked for a predetermined time and the transaction is recorded. When access is refused, the door remains locked and the attempted access is recorded. The system will also monitor the door and alarm if the door is forced open or held open too long after being unlocked.
In most access control solutions in use today, the system using a simple challenge-response system to allow a visitor access to a door or gate. When a credential is presented to a reader, the reader sends the credential’s information, in the form of an encrypted bit-string, to a control panel. The control panel compares the credential’s number to an access control list, grants or denies the presented request, and sends a transaction log to a database. When access is denied based on the access control list the door remains locked. If there is a match between the credential and the access control list, the control panel operates a relay that, in turn, unlocks the door. Therefore communication is typically taking place between the access control hardware at the door and a panel containing the system intelligence and database of authorized personnel. This communication traditionally has taken place along standard low voltage cabling creating a dedicated loop between the two devices. The advantage of this dedicated design is that it allows the systems designer complete end-to-end control of the system’s cabling, without concern for impact from other devices running on the same wire. The principal disadvantage is that the reader devices must be hard wired to the central panel to facilitate the communication, and therefore costly cable runs are required to every access-enabled door, and the system cannot be easily accessed from other geographical locations.
Why Ethernet for Access Control Systems?
Before we can examine the case for wireless technology, we must first convince ourselves that an Ethernet based solution is preferred over a traditional closed loop proprietary protocol. Here are the most compelling reasons to deploy an IP-based system:
Ubiquitous Existing Infrastructure Billions of linear feet of CAT-3, CAT-5(e) and CAT-6 copper cabling and optical glass fiber are already installed worldwide. TCP/IP networks are everywhere, and are now being used to support data transmission in almost every vertical market application in existence. Ethernet (IP) technologies are also widely understood by many types of IT and business process professionals; therefore it is easier to conduct discussions among disparate groups within a company to reach consensus and share network resources among users.
Finally, since TCP/IP networks are standards based, manufacturers can develop and bring to market products that are more cost effective and readily upgraded. Thus, with all of this infrastructure already in place, access control companies are wisely now providing their customers with the ability to leverage the existing network, and not requiring them to home run new dedicated low voltage cabling from every door controller and/or card reader to a centralized database server.
Since so much of this TCP/IP network infrastructure already exists – and in many cases is underutilized and contains spare capacity – it behooves the systems designer to consider using existing network cabling prior to specifying a solution that requires new low voltage (dedicated) cabling to be installed. Fortunately, data rates required for access control are very low, therefore the systems designer as a rule can easily obtain permission from the IT department head to allow the system to use the current TCP/IP network.
Access control systems are by their very nature spread out across fairly large areas. This is usually because the points of access / egress are at the edge or perimeter of the building or facility. Therefore, it makes perfect sense that the ideal technology to communicate between these devices is one tuned to fit these large areas. As a result, when discussing which platform to standardize upon – whether we are referring to a few doors on a floor of a small office building, or gates spread across a 15 square-mile major international airport – integrators need a solution that will readily scale from very small to very large. It is now generally accepted that Ethernet communication technologies provide the most robust, cost effective and easy-to-install solutions to deploy edge devices across a wide variety of geographic conditions. Ethernet networks are by design modular and highly scalable. Adding network subnets can be as simple as installing a managed switch or network bridge and laying additional cable. Using internal IP addressing, the number of network-based devices that can be installed to communicate with each other is very large.
Finally, and perhaps most importantly, the power of an IP-addressable system is most evident when examining its accessibility or visibility from other geographical locations. Inside the router – i.e. on the same subnet on the LAN – simply calling the internal IP address will provide instant access to the device. This is useful no doubt, however even more valuable is the ability to use network address translation (NAT) and port forwarding. By this means, any IP devices can be configured for easy access for external communication requirements from outside of the router serving the local area network. This means that, unlike closed loop dedicated point-to-point low voltage cabling, the IP-based system can be accessed from an Internet connection anywhere in the
Why Go Wireless?
It is not always the case that a wireless transmission solution is preferred. In fact, there is nothing more secure and reliable than a dedicated point-to-point cabled system. However, when transmission distances increase, and the bidding on the project becomes more and more competitive, it makes sense for the systems integrator to consider going wireless. Let’s examine a few of the principal factors:
Price is always an important consideration for any job, and in the case of government projects the most significant factor. Therefore, when designing a new network-based access control system, the choice must now be made between the price of the materials and labor associated with running dedicated cabling runs and conduit vs. the cost of the Ethernet based radio transceiver and power supply. Since long range wireless Ethernet radio transceivers are now below three hundred dollars, while the price of copper and conduit is rapidly increasing, it can often makes sense to examine the feasibility of a wireless solution for any distance over 50-75 feet in a building.
In the case of an outdoor installation, for example connecting from a main building to a perimeter gate access system, the case is even more compelling. The cost of trenching conduit in place can range from $15 to $35+ per foot, therefore a radio transmission system is almost always more cost effective in these situations. In part due to rising insurance and health care costs, labor rates have climbed briskly over the past two decades, making the labor component very significant in the overall cost of the project. Labor to pull cable can be difficult to estimate – especially in older buildings – but is very likely to be far greater than the few hundred dollar cost of the wireless radio equipment.
Taking the steps to minimize labor costs will very likely permit the integrator to submit a lower bid, win the job, get the job done faster and move their highly skilled personnel on to the next project.
Interruption in Service
On the job site, the use of wireless radio transmission means that the system can be installed during regular business hours, without as much concern for the interruption in service associated with pulling cable through the facility. Long cable runs inside a building or excavating trenches outdoors across the project site will very often cause an interruption in service of the company or agency. This interruption in service should be taken in to account when estimating the actual total cost of the cabled solution versus that of a wireless enabled system.
Trenching cable outdoors will in most cases leave an undesirable scar on the landscape. In many cases this is hard to quantify from a cost standpoint, but certainly most professional facilities managers will agree they would prefer not have their parking lot cut through unless absolutely necessary.
Negotiating in-ceiling cable runs under difficult conditions – for example in an older building that might be contaminated with asbestos – is a nightmare for all parties involved with the project. Furthermore, digging trenches on a job site to lay conduit for the network cable can be risky if the underground utilities in the area are poorly understood.
Better Products & Frequency Selection
New products from wireless manufacturers released in just the past year are much more compact, require less power than their immediate predecessors, and are very reasonably priced. Furthermore, several manufacturers have released products in the 900 MHz ISM band, providing a simple, unlicensed transport capable of transmitting access control data through long distances, including penetrating walls and foliage at the project site.
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