WLAN Design Best Practices And Challenges

With users expecting anytime, anywhere access from any device, demand for wireless networking is skyrocketing in the enterprise. But building WLANs today is far from easy. At Interop Wednesday, WLAN experts talked about what's required for designing reliable wireless networks and the challenges they face.

George Stefanick Jr., wireless network architect at Houston Methodist Hospital, who led a session on wireless network design said the organization's WLAN added 5,000 wireless clients in the past year and now counts about 22,000 clients. "That's a staggering number," he said. "We hear about the WiFi revolution. That's proof."

Five years ago, wireless pros didn't have to worry about so much about BYOD and the Internet of Things, he said. Today, those trends pose major challenges while users are quick to blame the WLAN when they run into problems.

Even though the connection between the WiFi client and the AP is only a small part of the overall network communication, it's the most important in terms of reliability, Stefanick said. Having a reliable WLAN depends on a strong design that begins with understanding what the network's requirements will be, he said. What will users be using WiFi for? What kinds of devices will be on the WLAN? What will be the application requirements? What will be the density and frequency requirements?

"Asking these questions gives you an idea of what you're getting yourself into," Stefanick said.

In his session, he described the different types of wireless site surveys – active, predictive, and blended – and recommended that organizations have experienced RF engineers conduct predictive site surveys. "Anyone can make a map green," he said.

Stefanick also discussed the problem of co-channel interference. Even though one might believe this interference is from microwaves or other non-WiFi devices, it's actually contention among the same channel WiFi radios. "Our own APs cause the most interference on today's wireless networks," he said.

Another session at Interop focused on WiFi in educational settings such as schools and universities. Networking expert Tom Hollingsworth, an organizer of the Tech Field Day events, moderated a panel of WLAN experts who discussed the unique issues of providing wireless connectivity for wide-ranging populations and high-density environments.

In higher-education settings, WLAN engineers can be faced with two sets of clients – full-time staff and students who live in the residence halls, Hollingsworth said. "Should you design your wireless network differently for both of those environments? Does one group have significantly different expectations?"

The question raised the issue of filtering policies and blocking traffic, which can be problematic in higher education where there can be academic expectations for unfiltered content. Ryan Adzima, senior consulting engineer at Presidio, described a situation when he took an ISP approach. "I didn't want policies I knew they'd break…I tried to figure out a way to make it work for everyone," he said.

The panel also tackled the question of high-density WiFi deployments, such as those needed to support sports stadiums. Keith Parsons, managing director of Wireless LAN Professionals, said no matter whether it's a stadium or a classroom, WLAN design should also start with the requirements.

"One AP per classroom isn't a design, it’s a marketing tactic," Parsons said.

Josh Williams, senior solutions strategist and sales manager at United Systems, said, "Design is so important to wireless, that maybe your first rule of thumb, if wireless isn't a competency of yours, is to find someone who has it."