Your planned Wi-Fi deployment – coverage, capacity, flexibility
Most business will at this stage have developed some sort of Wi-Fi connectivity, be it at the low end, using the firewall / router’s inbuilt Wi-Fi capability, or the more expansive controller or controller-less enterprise grade deployments. This article will deal with the requirements of developing or transitioning to the latter.
As technologies integrate more into our daily business and personal lives, the requisite technology to support and make maximum use of these technologies have similarly a requirement to adapt to our changing needs…One has to have a pretty isolated environment to NOT require a modern smart phone, a PC with internet connectivity and an electronic mailing system. This article makes the assumption that the reader has similar needs.
Wi-Fi signal and bandwidth delivery should be planned on the requirements of:
Coverage:
The common misconception is that an area is best served by a minimal number of Wireless Access Points (AP’s) and to boost the power. With the ever increasing number of such devices in the field, the electronic cacophony of noise is overwhelming, and best practice suggests the minimum power setting available to deliver optimal bandwidth to the client device.
Capacity:
Albeit that a single AP may well successfully connect 30, 40 or even 50 concurrent users, the available bandwidth still has to be shared between all of the users. As a real world example, a single AP serving 50 students, all signing on at the same time to view a Youtube™ clip, will deliver an unsatisfactory experience to the end user. Limiting concurrent connectivity to say, 30, will deliver a much better user experience.
Flexibility:
You may well have clearly defined to your current needs, but know that the availability of a quality Wi-Fi solution will lead to the increased use thereof, and thus any design should be flexible enough to cater for a growth in requirements. Your technology decisions should be capable of integrating with a larger solution requirement.
Let’s start
First, determine the number of clients you expect to serve, keep in mind that each person typically has a laptop, a smartphone, possibly even a tablet, thus one person translates to 3 clients. Also consider that barcode scanners and mobile Eftpos machines add to the load.
Secondly, consider the type of traffic you expect on the network. A user with a hand scanner is likely to require less bandwidth than a database user.
Now consider the location, the number of access points and mount locations. We make use of graphical tools to predict possible outcomes. These tools place the AP’s, maps the signal strength to all locations, and provides a pretty accurate view of the expected bandwidth at each location. See the example below.
Define your needs by asking some simple questions:
- How many users / clients do you expect to be connected at any one time
- What are the capabilities of the client devices, is it a dumb Chromebook or a high end laptop?
- What applications would you use, and where would they be hosted
- Consider folks on the move, the number of phones, areas of high user concentration (water-cooler, kitchen, reception)
- Include Guest network provision and user on-boarding
Existing infrastructure
Up to a few years ago, Wi-F- access points could well be served by existing switching and cabling. Todays’ Access Points require gigabit (or better) connectivity to fully deliver bandwidth to the client device, and is often found to be the “choke” point in a poorly designed solution.
Power over Ethernet (PoE) allows for the delivery of the requisite power to the access point; often mounted far away from available power outlets. The modern products have a higher power requirement to the AP’s of yesteryear, and this should be part of your design consideration. Consider power delivery from your chosen switch gear. The standard is 802.3af (15 Watts nominal) caters for most smaller AP’s, while the newer 802.3at, also known as PoE+ (25 watts+) caters for the feature rich AP range.
Access and maintenance
Many solutions call for a downward facing Access Point, as the antenna design within the unit has maximum signal delivery in this configuration. Rule of thumb is, higher is better, but keep in mind that devices may need physical access at some time.
Example deployment
A small company with 20 office staff require a Wi-Fi solution with sufficient bandwidth to connect all user devices. There is no existing data cabling, and the client has opted not to cable any device to the network. Thus all users will have to be accommodated on the provided Wi-Fi network. They have specified 802.11ac, as most of their laptop and other connected devices support this technology.
They are budget conscious, but require a solution that can expand to their growth needs
Solution
The HP Aruba IAP 205 fits both their requirement and budget. Connected to the HP 2920 24G PoE switch makes for an easy, affordable and upgradable solution. The ceiling mounted IAP’s will be cabled to the switch and well within the 100 meter limitation of CAT6 cabling. PoE is provided to all IAP’s, reducing complexity and cost of deployment. The solution will be configured to provide both authenticated staff access, as well as unauthenticated guest access on a separate Station Set Identifier (SSID)
The complete installation will be adequately serviced by 9 AP’s, data rate 300 Mbps on 802.11n, 800+Mbps 802.11ac
Need more info?
Call me on 027 524 9995 or email me anton.schutte@selectit.co.nz
Anton Schutte
