Best Practices

The majority of Wi-Fi networks being deployed today utilize a centralized architecture consisting of numerous thin (dumb) access points tied to controllers (WLAN Switch) in central closet. This legacy approach will exhibit significant performance issues with the advent of 802.11n, which will bring a 5X increase in Wi-Fi network traffic.

Consider the following when deciding between a distributed or centralized architecture:

	Distributed	Centralized	Advantage Defined
Packet Flow	Efficient	Inefficient	Centralized architectures force all traffic to transit to a controller in the core, increasing core network congestion. Distributed architectures forward traffic directly to its final destination.
Latency/Jitter	Low	High	Centralized traffic must first traverse the network to the controller and then undergo processing (QoS, tagging, encryption, etc). This additional routing results in increased congestion, latency, and jitter.
Access Point Capacity	3.6Gbps	300Mbps	Centralized architectures typically offer 1 or 2 radios per access point, limiting the Wi-Fi capacity in a given area. Distributed architectures integrate up to 16 radios providing far greater capacity.
Deployment	Simple	Complex	Centralized architectures require significant number of APs, antenna, cable and controllers deployments that increase complexity and install time. Distributed architectures integrate components to reduce cabling, simplify installs and reduce costs.
Intelligence	Efficient	Inefficient	Centralized architectures place intelligence (QoS, security, tagging, etc) in the controller where all traffic is processed. Distributed architectures place intelligence at the edge, like wired networks, improves traffic handling and increase performance.
Reliability	Resilient	Problematic	With centralized architectures loss of a single AP has little impact; however loss of a controller can mean loss of the entire Wi-Fi network. Distributed architectures integrate intelligence throughout the network, eliminating single points of failures.
Scalability	Incremental	Costly	Each new AP added to a Central controller adds to the processing burden of the controller which slows performance for all APs to a point where additional controllers ($$) are required. Distributed architectures easily scale as additional processing capability is added with each new wireless access device.