There are many things to take in to consideration when designing an on premise wireless infrastructure, whether it be a new installation or a technology refresh. Of course, a refresh is usually easier since the infrastructure is already in place but if the initial install was implemented incorrectly it can be more work and more costly to rip it all out and start over as opposed to a new build-out. In either case, proper planning is key to a successful implementation and the management of the wireless infrastructure is one of the most important tasks to consider.
There are three options when it comes to wireless management. They are on-premise, cloud-managed and cloud-controlled. On the surface it may seem as if these are just three different ways to accomplish the same task but don’t be fooled. Although there may be advantages to each method I can assure you that not all wireless solutions are created equal.
Here are some of the advantages and disadvantages to each:
This model consists of a physical or virtual appliance which contains the device configuration for the access points as well as the overall network configuration. The APs are just a connection point for the users and act as a single cluster of antennas. Wireless traffic is usually tunneled back to the controller before being dumped onto the wired network and the controller makes the L3-L4 decisions when it comes to traffic management. The biggest advantage of an on-premise controller is that the Wi-Fi infrastructure is not dependent on any outside connectivity. Although there may be centralized management tools available, on-premise controllers operate independently of the cloud. Users are able to connect and changes can be made even if there is no Internet connection available. There are no annual license fees to consider, although the cost of annual maintenance contracts can and often do counter-act the savings from license fees. Although not required, maintenance contracts allow for software updates which contain new features and bug fixes so it is usually a good idea to keep your maintenance active but even if you choose not to purchase or renew your maintenance you don’t lose the functionality that you already have.
The disadvantages of an on-premise controller are cost and maintenance. The initial startup cost is usually higher than the other two options since, in addition to AP hardware costs, you have the cost of the controller itself. You must also license the controller for each AP that you want to add to the mix but since these licenses are perpetual it’s a one-time cost. Still, this can make the on-premise controller option unattractive for low-budget consumers.
Vendors: Aruba, Cisco, Ruckus
The cloud-managed model has one advantage over both the on-premise and the cloud-controlled models which is that each AP can work independently of any other device while still able to be centrally managed. In this model, each AP is autonomous and contains its own device and network configuration but is not configured directly. Instead, the administrator connects to a cloud controller and modifies the configuration for each individual AP or AP group which is then pushed to or pulled by the AP itself. It is the AP that controls the traffic rather than the controller. Any AP failure will not affect the other APs on the network. On top of that, there is no controller to purchase which translates to an initial cost savings and updates are done in the cloud which eases the burden of maintenance.
There are two disadvantages that make this model less attractive than the on-premise one, namely licensing and renewals. Each access point must be licensed in the cloud and must be renewed annually to maintain control of that AP. This can be costly for an organization with a large number of APs. Also, if the license is allowed to expire, the administrator may lose the ability to make changes to the configuration. That said, the AP will usually continue to function with the current configuration that is on it at the time that the license expired so connectivity is not interrupted.
Vendors: Aerohive, Ubiquiti
This model is like the on-premise model in that each AP is configured and managed by the cloud controller and it is the controller, not the AP, which controls the traffic and access policies. It has the advantage of lower maintenance since the administrator doesn’t have to worry about updates because the vendor maintains the controller.
This model is by far the worst of the lot and, in my humble opinion, should be avoided at all costs. Like the cloud-managed solution it requires annual licensing and renewals. However, unlike the cloud-managed and on-premise solutions, Internet connectivity is an absolute must because if the AP loses connectivity to the cloud controller then traffic will stop. This also means that if the license is not renewed for any reason the APs cease to function and become paper-weights. Imagine a college classroom full of students taking a server-based exam and suddenly the entire room loses connectivity because of an Internet outage or the administrator forgot to renew the licenses. To me, the risk of such a setup outweighs any benefits.