IEEE 802.11n and Architecture Redux at Interop: Page 7 of 7

At the end of the day, each enterprise WLAN vendor offers some level of flexibility in regards to centralized or distributed architecture. And much as we see in partisan politics, the reality is somewhere closer to the middle than at the extremes. The architectural choices that an enterprise makes depend more on its client base and preferred traffic patterns. Guest traffic will almost surely be centralized and dropped into the DMZ. Organizations with a decentralized IT implementation and many servers at the edge or branch offices will lean toward a distributed switching model, bypassing routing all the wireless traffic to the core and back again. But smaller single-site organizations that host a single router at the core are better off containing the VLAN "explosion" at the edge and sticking to a centralized model. In the same vein, IT staff who can't control their organization's edge switching infrastructure will prefer the overlay model.

Here's some free advice: Don't let your WLAN vendor dictate your architectural decision. Choose the architecture that works for your organization's traffic flows, security policies and network management routines, and then select a vendor that best matches them. If you find yourself attracted to a WLAN vendor that requires redesigning your wired network toward distributed, which many mean pushing VLANs out to the edge and redesigning your firewall/ACL policies, or toward centralized, which may increase distribution layer traffic and potentially add latency, you need to take a step back and carefully reconsider your original choices. There's no white knight for enterprise WLANs. If there were, the healthy competition that exists between Cisco and everyone else wouldn't exist.