If you're in the market for a new, enterprise-class WLAN, one of the first decisions you’ll need to make is whether to choose a traditional on-premises controller or a cloud-managed solution. Enterprises typically manage a WLAN with on-premises controllers, but cloud-managed WLAN has been steadily gaining traction. The idea of shifting the configuration and control of the entire WLAN to a cloud service provider can be a tough pill to swallow for many veteran network architects, but more enterprises are seeing the benefits.
Still, an on-premises controller may be the better fit for some enterprises. In this article, I'll look at the pros and cons of both WLAN architectures.
The main benefit of being able to manage a WLAN from the cloud is flexibility and ease of setup. If your organization is geographically dispersed, a cloud-managed WLAN lets you control your entire wireless network form a single interface. In contrast, on-premises solutions typically have to be deployed and separately managed at each location.
Another benefit is scalability. Because your controller is managed by a service provider in the cloud, you no longer have to be concerned with hardware appliance scalability limitations. With on-premises controller appliances, you can bump up against a maximum number of wireless access points that can be managed on a single platform. Expansion beyond that means either upgrading to a larger appliance, or having to break out and manage multiple controllers. For example, a Cisco 5500 series wireless controller supports a maximum of 500 APs. With a cloud-managed WLAN, there is no maximum limit to worry about.
Moreover, because the underlying controller software and infrastructure are managed by the service provider, your infrastructure staff doesn't have to spend time and effort on updating and patching of the WLAN equipment. All you have to do is schedule an upgrade window when you want the updates to occur. This is an often-overlooked benefit that can actually be a tremendous time and money saver in the long run.
Despite the increasing popularity of cloud-managed WLANs, there are still some reasons why you may want to stick with an on-premises controller solution. First off, you may want to re-use your existing controller and simply upgrade APs for increased performance. Many organizations want to upgrade their current 802.11n WLAN to one that supports 802.11ac standards. In most cases, the controller that manages the 802.11n network can be reused, and the the 802.11n APs replaced with 802.11ac capable units. From a cost-savings perspective, this may be the best option.
Secondly, your WLAN may need more advanced control and capabilities with fine-tuning at a local level. While cloud-controlled WLANs are becoming more sophisticated by the day, they still don't match the granular control that an on-premises WLAN solution provides. If control is something you absolutely need, then a cloud-managed WLAN is probably not the best choice.
Third, while most of the major WLAN vendors now offer cloud-controlled WLAN solutions, you may find that the specific AP hardware and antenna options are limited when compared to hardware that's compatible with on-premises controllers. If you're deploying a WLAN in areas with plenty of interference and obstructions, you may need the ability to use specific AP and hardware antennas that are not yet compatible with cloud-managed solutions. Even though WLAN vendors are working to close the hardware compatibility gap between cloud-managed and on-premises hardware options, on-premises options still maintain an edge today.
Finally, you will want to stick with an on-premises architecture if you don't have faith in your internet connection. Because the WLAN receives its configuration and intelligence from the public cloud through the internet, having consistently available internet connectivity is a must. In WLAN deployments where uptime is critical, internet redundancy is crucial. If this can't be confidently achieved, then an on-premises controller is the better choice.