The actual selection of hardware should be determined by establishing the requirements for the project, determining the available budget, and verifying that the project is feasible using the available resources (including providing for spares and ongoing maintenance costs).
Choosing wireless components, the price tag is the single factor that usually receives the most attention. The old saying that “you get what you pay for” often holds true when buying high tech equipment, but should not be considered absolute truth. While the price tag is an important part of any purchasing decision, it is vital to understand precisely what you get for your money so you can make a choice that fits your needs.
When comparing wireless equipment for use in your network, be sure to consider these variables:
Will the equipment you are considering work with equipment from other manufacturers? If not, is this an important factor for this segment of your network? If the gear in question is standard, then it will likely interoperate with equipment from other sources.
This is not something inherent in a particular piece of equipment. A device’s range depends on the antenna connected to it, the surrounding terrain, the characteristics of the device at the other end of the link, and other factors. It is more useful to know the transmission power of the radio as well as the antenna gain (if an antenna is included). With this information, you can calculate the theoretical range as done when looking at link budget calculations
How sensitive is the radio device at a given bit rate? The manufacturer should supply this information, at least at the fastest and slowest speeds. This can be used as a measure of the quality of the hardware, as well as allow you to complete a link budget calculation. When considering radiosensitivity, a lower number is better.
Manufacturers consistently list the highest possible bit rate as the “speed” of their equipment. If throughput rate information is not available for the device you are evaluating, a good rule of thumb is to divide the device “speed” by two, and subtract 20% or so. When in doubt, perform throughput testing on an evaluation unit before committing to purchasing a large amount of equipment that has no official throughput rating.
- Required accessories
To keep the initial price tag low, vendors often leave out accessories that are required for normal use. Does the price tag include all power adapters? For example, DC supplies are typically included; Power over Ethernet (PoE) injectors typically are not. Double-check input voltages as well, as the equipment is sometimes provided with a US power supply. What about pigtails, adapters, cables, antennas, and radio cards? If you intend to use it outdoors, does the device include a weatherproof case?
- Power consumption.
For remote installations, power consumption is the most critical issue. If the devices are to be powered with solar panels, it is very important to select the ones that require the lowest possible power. The cost of solar panels and batteries can be much higher than the cost of wireless devices; so lower power consumption can result in a much lower overall budget.
- Other factors.
Be sure that other features are provided to meet your particular needs. For example, does the device include an external antenna connector? If so, what type is it? Are there user or throughput limits imposed by the software, and if so, what is the cost to increase these limits? What is the physical form factor of the device? Does it support POE as a power source? Does the device provide encryption, NAT, bandwidth monitoring tools, or other features critical to the intended network design?
By answering these questions first, you will be able to make intelligent buying decisions when the time comes to choosing Wireless networking hardware. If you prioritize the questions and press the vendor to answer them before committing to a purchase, you will make the best use of your budget and build a network of components that are well suited to your needs.